Soured Fruit Beer
The acidity and fruity characteristics in many mixed-fermentation beers make them good candidates for fruit additions. It is not recommended to put fruit into a beer to cover up some major flaw or off-flavor. Fruit can complement a good beer but it will likely not fix problems. Quality fruit is expensive and you'll want to start from a good base if you are going to invest the time and money in good fruit for a beer.
Some producers use the term maceration to describe the addition of fruit or herbs to a beer. Maceration in beer is the extraction of flavor-active and colored compounds as well as other constituents of fruits and herbs by soaking them in the beer. The rate at which compounds are extracted during maceration depends on factors such as temperature and pH.
For commercial brewers in the US, any ingredient not on the TTB exempt lists needs to be approved by the TTB regardless of where the beer is sold. When seeking approval, it is helpful to show previous use and scientific articles supporting the safety of consumption of the ingredient being used. For example, if the item is on the FDA GRAS list (or potentially FDA approved Food Ingredient and Packaging Inventories; see also advice from Andrew Zinn), then providing this information to the TTB or possibly having the FDA GRAS department work with the TTB for approval can help. See also Formulas for fermented products on GPO.gov.
Michael Thorpe and Milk The Funk maintain a list of ingredients that have been approved by the TTB for a specific brewery to use but are not on the TTB exempt list. Help us out by adding your TTB approved ingredient to the list, or use this list to help you get approval for an ingredient that your brewery uses.
When To Add Fruit
When to add the fruit depends on the style of beer and what the brewer is going for. Generally, fruit is added after a sour or mixed fermentation beer has finished aging and maturing. This preserves the fruit character more than other methods. For example, a mixed fermentation sour beer might take 6-12 months for the Brettanomyces character to develop fully. After this maturation, the fruit should be added, and then aged for another 1-2 months. For a kettle sour, the same rule applies, but the time frame is generally much shorter. Since kettle sours generally mature much faster than mixed fermentation beers, fruit can be added much sooner. For example, if the kettle sour is done fermenting after two weeks, fruit can be added at that time.
Another method would be to add the fruit earlier on during the aging process. This can help extract more from fruit skins or seeds, but some of the more delicate aromas and flavors of the fruit could age out of the beer in that time. For example, Belgian kriek style beers are sometimes aged on cherries for 6-12 months, which is believed to be the time required to fully extract the character from the cherries and pits . A longer period of aging time on fruit can also result in less "jammy" and fresh fruit flavors, but also a more subtle and complex fruit character.
A combination of adding fruit earlier on in the fermentation, and then again after the beer has matured is another technique that brewers have used. For example, The Lost Abbey's Framboise de Amorosa is aged in a wine barrel for a year and during that time receives three separate additions of raspberries .
Fruit juice can also be added at bottling time and is usually used as the priming sugar source when this is done. This is considered an advanced technique that requires knowledge of the amount of sugar in the juice. The brewer should calculate the amount of sugar that is in the fruit juice and how much fruit juice should be used so that over-carbonation does not become a problem.
Fruit can be added at any other point in the brewing process as well. For example, some brewers have tried adding fruit to the mash, boil, or during primary fermentation. Adding fruit this early in the brewing process generally results in less fruit character. Some fruits might benefit from these different approaches, such as citrus based fruits being added in the boil (see the Usage Suggestions below).
Pasteurizing fruit is optional if the beer is a mixed fermentation beer (contains living Brettanomyces). Generally, the low pH, alcohol, and hops will prevent the growth of any microbes on the fruit. there is a possibility of wild yeast living on the fruit potentially adding to the character of the beer. If this is not desired, for example for kettle sours where the brewer does not want to risk contamination of their cold side equipment, the fruit can be pasteurized or the brewer can use a pasteurized fruit product such as a puree or juice. For tips on pasteurizing fruit, see this AHA article. For more information on the forms of fruit (puree, juice, whole, etc.) and various concerns/approaches to using those forms, see the Forms of Fruit below.
Aging Vessels and Refermentation
In general, the fruit is added to a new vessel of some sort, and the beer is gently transferred to this new vessel to rest on the fruit for the determined re-fermentation time. Some homebrewers will also dump fruit directly into the primary fermenter itself. This can be a challenge in regards to minimizing oxygen due to splashing and physically getting fruit into certain types of fermenters such as glass carboys that have a small opening. For homebrewers, vessels such as plastic buckets are a good option because fruit can easily be added and removed afterward. When racking beers to another vessel, the vessel should be purged with CO2 if possible, although this isn't always necessary (if the beer does not seem to contain a lot of acetic acid or ethyl acetate, purging the oxygen may not be needed). The vessel should be cleaned and sanitized beforehand.
For commercial brewers, having a screen of some sort at the bottom of the vessel is beneficial for helping to separate the fruit material from the beer after the aging. For example, Funk Factory Geuzeria built a tap and stainless screen for aging sour beer on fruit in an oak barrel. Some brewers also use IBC Totes for aging beer on fruit. Puree or juice can easily be added directly to an oak barrel, but there must be enough room for the fruit and the re-fermentation.
Fruit displacement isn't a huge concern; 10 pounds of fruit generally requires an extra gallon of headspace (the exact volume depends on the volume of the fruit ). However, the fruit will usually re-ferment, causing a blow-off, so allowing for extra headspace is a good idea. This site might assist with calculating the displacement volume of fruit.
(To do: add info from this thread: https://www.facebook.com/groups/MilkTheFunk/permalink/1770502506311289/)
- MTF thread on Speidel's Variable Capacity tank BO. Winemaking equipment vendors such as GW Kent also sells variable capacity tanks.
- Altbrau Instagram post on using plastic Speidal fermenters for fruit refermentation.
Whenever fruit is added to a beer that hasn't been pasteurized, a re-fermentation will occur because new sugars from the fruit are introduced to the microbes that are still alive in the beer. This re-fermentation can take some time to being, and some time to finish, depending on the beer. In general, the fruit should be allowed to finish fermenting before packaging. An alternative method is to ferment the fruit more quickly in a separate fermentation tank with S. cerevisiae and then blend the fermented fruit into the beer; see Other Alternative Processing and Fermentation Methods for more information. For information about packaging beer with unfermented fruit/puree/juice, see Unfermented Fruit Beer.
Regular beers and kettle sour beers often contain living S cerevisiae as long as they are not aged for too long (less than a month). Mixed Fermentation sour beers where Brettanomyces was pitched will most likely still contain living Brettanomyces cells even after a year or two of aging. In the case of Brettanomyces, only a small population of surviving cells is enough to kick off a re-fermentation. For beers that have aged for a very long time in very sour conditions, fresh Brettanomyces or wine yeast can be pitched to ensure re-fermentation of the fruit.
When adding fruit to a non-pasteurized beer that does not contain living Brettanomyces but does contain living S. cerevisiae (for example, kettle sours), a re-fermentation will often occur a day or two after adding the fruit. This re-fermentation can last 1-2 weeks until the sugars from the fruit are fermented. Sours such as kettle sours that do not contain living Brettanomyces can be treated like adding fruit to any other type of "clean" beer (see this AHA article, for example). Beers that are fully pasteurized, for example from a flash pasteurizer, or aged for longer than 6 months or so, will not re-ferment the fruit because all of the yeast is dead. Fruit that is added to a sour beer that does not contain living Brettanomyces should be pasteurized somehow so that wild yeast does not over-attenuate the beer (see the previously mentioned AHA article for pasteurization options), or the brewer can use ascetic concentrate, juice, or puree that does not need to be pasteurized.
There are different considerations when adding fruit to aged sours that contain living Brettanomyces. In general, there is no reason to pasteurize the fruit when adding it to a sour beer with Brettanomyces, so this step can be skipped (most of the wild yeast and bacteria on the fruit won't be able to grow, and if there are their impact will be minimal if any at all). The brewer may choose to pasteurize the fruit if adding it to a beer that has Brettanomyces but does not have lactic acid bacteria in the case where they do not want to risk the beer getting a slight increase in lactic acid from any potential lactic acid bacteria on the fruit, although this is usually not a concern since any wild lactic acid bacteria will probably not survive well in the harsh conditions of the already fermented Brettanomyces beer. When adding fruit to an aged, non-pasteurized sour beer that contains Brettanomyces, a secondary fermentation will generally occur after a few days of adding the fruit, and will generally last 1-2 months (see contact times below). A seven-day lag time is not unheard of, as this follows the growth cycle of many Brettanomyces strains. The visual indicators of this fermentation will depend on the strain(s) of Brettanomyces and other microbes that have survived the previous aging process, and can range from active fermentation to developing a pellicle to having no visual fermentation at all. Active fruit fermentation may cause fruit particles to clog the airlock or bung and prevent the vessel from venting pressure. This may cause the airlock to shoot off or worse. The Rare Barrel prevents this problem in vigorously re-fermenting beers by stabling foil over the bung holes of barrels of actively fermenting fruit beer rather than using a bung (~52 minutes in). Raf Soef uses stainless mesh from a tea ball on the bottom of bungs to prevent fruit pieces from clogging the bung or airlock . Raf also suggests filling only 80% of the capacity of the vessel with fruit and beer, and then topping up after the re-fermentation of the fruit .
When using whole fruit, it is typical for the fruit to be carried to and held at the top of the fermenter by the carbonation. Some producers have voiced concern over the fruit sitting for prolonged periods of time in contact with air and prefer to push the fruit cap down periodically (and to ferment in such a vessel as to allow this) (~40 minutes in). If you are fermenting in carboys and feel that you are getting acetic character from the fruit cap being in contact with air you can swirl the carboy periodically. Note that many who have used whole fruit have not noticed any problem with a fruit cap being in contact with air, so you may or may not find that this is a concern for you.
Adding yeast when adding fruit is an option, but not necessary, even for really old sour beers. There should still be some living Brettanomyces in the beer. Yeast could be added optionally, which might help reduce the effects of added oxygen or speed up the re-fermentation process, but it is generally not necessary.
Changes To Alcohol Content
Unless very large amounts are added, most fruit does not greatly change the overall alcohol content of the beer that it is added to since most fruit with a high water content is within the 1.045-1.060 starting gravity range, or lower . Wine grapes are a notable exception to this, which have high starting gravities that produce 10-15% ABV wines. When adding fruit with average gravities to beer and allowing it to re-ferment, small changes to the ABV can occur based on the amount and type of the fruit, the format of the fruit, and the ABV of the beer. For example, if a fruit puree that has a typical gravity of around 1.045 is added to a 10% ABV beer, the more puree that is added then the more it will dilute the total ABV of the beer. Fruit concentrates and dried fruit may add more alcohol than when added in juice/whole fruit format because the water content of the fruit has been removed, although lower dosages of concentrate/dried fruit might result in only small or insignificant ABV increases. The gravity of whole fruit or juice can be fairly easily determined by using a refractometer. Matt Miller of Sour Beer Blog provides a calculator that can help predict alcohol changes based on the gravity and quantity of the fruit (and beer), and Michael Tonsmeire of The Mad Fermentationist provides a calculation as well.
Forms of Fruit
General Forms of Fruit
Fruit is available to the brewer in multiple different forms.
- Whole or sliced fresh - Use a CO2-purged keg or minimize headspace in a carboy. Mold and acetic acid bacteria can grow on the skins of floating fruit . Brettanomyces can also produce acetic acid in the presence of O2, and it is possible that this is the source of acetic acid sometimes found in beers with floating fruit rather than acetic acid bacteria. Some brewers like to swirl the fermenter every few days or to keep the alcohol in contact with the fruit, though some others report no ill effects from not swirling the fermenter (and this is impractical in commercial settings). If using a barrel or larger fermenter, you may try using a punch-down technique. If punching down the fruit, purge the headspace of the vessel with CO2 to avoid oxygen exposure to the beer. Allow the fruit to get fully or possibly even over-ripe (not rotten) for best flavor. Whole fruit may take longer to ferment but it also can give the most complexity 
- Whole or sliced frozen - Bulk freezing fruit has a few main potential benefits. First, freezing fruit helps to break down cell walls, which may make the fruit easier to access for yeast and bacteria in the beer . Freezing fruit can also reduce the microbe populations present on the fruit. Note however that freezing does not kill all the microbes on the fruit and many pathogens and beer spoilers can survive freezing (freezing does not pasteurize the fruit). Finally, freezing fruit allows the brewer (especially the homebrewer) to take advantage of local and seasonal fruits when they may not have a use ready for those fruits in season. Frozen fruits are also available as IQF, or individually quick frozen fruit. IQF fruit is frozen but each berry is distinct rather than a single frozen mass. This allows for easier handling, helps prevent clumping, makes for easier fitting of fruit into small openings in carboys or barrels, and allows screening and removal of bad looking fruit. The cell walls of IQF fruit are less broken down than bulk frozen fruit, so there might be a slower extraction rate when using IQF . Defrost frozen fruit in the microwave or in the fridge over night. The fruit doesn't necessarily have to come all the way up to cellaring or room temperature. Adding frozen fruit without thawing it first is probably fine as well. The beer and frozen fruit will come back up to ambient temperatures over night .
- Pureed fresh - pureeing fresh fruit has the benefit of extracting the fruit flavor faster. It also sinks to the bottom of the fermenter , so the problem of floating whole fruit is avoided. Puree can be difficult to rack the beer off of, and more beer may be lost compared to using whole fruit (see this MTF thread for tips on filtering out or racking off of puree as a homebrewer). Some brewers choose to heat pasteurize freshly made puree.
- Aseptic puree - Same as "Pureed Fresh", but has already been pasteurized. This is usually the case for commercially available puree. We recommend Oregon Specialty Fruit, The Perfect Puree, or iTi Tropicals for quality commercial puree. These purees often have antioxidants such as citric and absorbic acids, cane sugar, and other juices added to them . Check the ingredients list of any product before ordering it. Much like fresh purees, aseptic purees or pulps may result in a fair amount of volume loss at packaging, and some puree making it into the final package can be problematic for gushing (see this MTF thread for tips on filtering out or racking off of puree as a homebrewer) . See the Oregon Fruit webpage for tips on usage amounts and how to use puree for brewing (they recommend 1/2 to 2 pounds of puree per gallon of finished beer). Evan Coppage demonstrates how to use a tri clover compatible clamp to more easily open a bag of Oregon Fruit puree.
- Concentrates and extracts - Concentrates can lose aromatics due to the process, and are generally not as recommended. However, some manufacturers such as Kings Orchards uses a process that reintroduces the aroma back into the concentrate . Other manufacturers have been reported to produce high quality concentrates, such as Coloma. Some brewers use concentrates/extracts blended with puree or whole fruit. See this MTF thread for a discussion on the benefits of using concentrates. Extracts tend to be more singular in flavor, and combining different extracts from different companies has been suggested (or blending extract with real fruit/puree to help boost the flavor of certain fruits such as blueberries). Concentrates can increase the alcohol concentration in beer that it is added to more so than other forms of fruit because of the removal of most of the water naturally found in the fruit during the production of the concentrate; taking a brix reading of the concentrate with a refractometer or hydrometer and using brewing software to calculate the increase in alcohol can be a way to estimate this increase.
- Juice - Make sure there is no sugar or preservatives added . R.W. Knudsen and Lakewood Organic brand juices have been recommended if available . Juice ferments out faster than whole fruit. This gives the advantage of being able to add a little bit at a time to the secondary fermenter, and being able to add to taste.
- Dried/Dehydrated - Try to make sure they are oil-free. Oils can be considered a processing aid, and don't have to be listed on the ingredients list. Sulfur dioxide amounts used in dried fruits is diluted enough to not have a great inhibitory effect, and sulfured dried fruits are safe to use. See also this post by Gail Ann Williams on the benefits of using dried apricots. Dried fruit can potentially increase the alcohol more so than other forms of fruit because the drying of the fruit removes the water.
- Zest - the zest (outer layer) of citrus fruit is often used in beer. It is often added to the end of the boil, but tinctures can also be made and added after or during fermentation, or citrus zest can be added to the beer directly.
- Frozen - Many exotic fruits are available at world markets in frozen format.
Prefermenting, Brining, and Other Pre-processing Methods
- Editor's note: This section was written by Matt Firetto and reviewed by Jeffrey Airman and Dr. Bryan Heit.
Overview of Fermented Fruits
Performing a fermentation before introducing fruit to a beer can help provide more complex fruit flavors, and in many cases create new savory flavors not found in the raw fruit. Some of the most common fruit based fermented products are simple salt based "Lacto-fermentations" (pickling). These fermentations utilize naturally occurring Lactobacillus and other microbes on the fruits skin to ferment the fruit, while the salt helps to reduce yeast activity (both fermentative and oxidative yeast) and other harmful spoiling microbes. A common method calls for simply salting fruit at a rate of 2% by weight (20 grams salt for 1kg fruit) . General best practices for food based "Lacto-fermentations" should be followed such as: even salt distribution, minimizing oxygen contact with fruit, and fermentation temperatures at or slightly above room temperature. If the fruit does not release water to create a natural brine, a brine solution can be made to help ensure a more even distribution of salt and create a lack of oxygen in the fermentation vessel. Common fruits utilized for "Lacto-fermentations" include lemons, blueberries, cherries, pineapple, gooseberries, plums etc. Other spices or herbs can also be used to add additional flavors during fermentation. Similar to a brine, another method documented in "The Noma Guide to Fermentation" utilizes a honey/water/salt solution with fruit to produce a Lactobacillus fermented syrup flavored with fruit and/or spices .
Resources For Fermented Fruits
"The Noma Guide to Fermentation" by René Redzepi and David Zilber includes detailed information on how to perform "Lacto-fermentations" and other fruit/vegetable based ferments. This book provides a general framework and guidelines that can work for a variety of fruits, with a focus on creating new flavors and experimenting rather than an exhaustive list of recipes. Sandor Katz has also written several books on home fermentation that provide detailed information on a wide variety of fermented products including fermented fruits. The Ferment All Things Facebook group includes many posts of various fermented fruits and vegetables, and is a good source for ideas and guidance.
Concerns When Utilizing Pre-fermented Fruits
High salt content is one of the main concerns when utilizing "Lacto-fermented" fruit products, especially when used at the higher end of recommended fruiting rates. Some fermented fruits (ex Moroccan style preserved lemons) can have a significant amount of residual salt in the final product. Excess salt can be removed by simply washing off excess salt , or by soaking the fruit for a short time in clean water. Fermented fruit products can have a significantly different flavor profile compared to raw fruit, so fruiting levels may need to be adjusted depending on the intensity of the fermented fruit product and base beer. Due to the wild and spontaneous nature of these types of ferments, various wild yeast and bacteria are typically present. Depending on a beer's residual sugars, these microbes may or may not be a concern. If this is a concern, fermented fruit can be heat pasteurized or frozen to help reduce the potential for these microbes to alter the beer . If fermented fruits are introduced early in a beer fermentation, the overall yeast/bacteria character of the beer fermentation can be impacted.
Other Alternative Processing and Fermentation Methods
- Jamil Zainasheff recommends fermenting the fruit into a fruit wine using a S. cerevisiae strain in a separate fermenter. Doing so allows for a fast fermentation since fruit consists of mostly simple sugars, and allows the brewer to blend the fermented fruit wine into the finished beer at the desired proportions. This reportedly can produce "brighter" fruit character than fermenting fruit in sour beer for a longer period of time. The fruit would have to be in liquid format, and high sugar fruits such as wine grapes might need to be diluted with water first in order to ensure a quick fermentation. See comments by Zainasheff in this MTF thread for more details.
- Caramelization of fruit juices, smoking, spontaneous or kombucha based pre-fermentation, and other culinary inspired methods can also be used to help transform fruit. Paradox Beer Co's Pineapple Upside down sour was created using a candi syrup created from pineapple juice raised to a PH of around 6 with baking soda to increase the maillard effect and provide a more intense long lasting caramelized flavor .
Related Milk the Funk Facebook Group Posts and Other Links
- Jeffery Airman of Paradox Brewing discussed some of these methods and comments include ideas and experience from others.
- Brian Detweiler posted about "Lacto-fermented" blueberries and others provide examples of fermented fruits used in beers.
- Addressing concerns of too much salt when used in beer.
- DeWayne Schaaf posted about Umezuke (Japanese salt preserved plums).
- Examples of fermented fruits in beers (Google Doc).
- Escarpment Labs blog article on kahm yeast.
- MTF thread by Morgan Grant McGaha on using carbonic maceration for fruit before adding to beer.
- Carbonic maceration
- Thread about instant haze formation when blending wine with sour beer, and what to do to clear it.
Fruit varieties and usage suggestions
Specific notes on select fruit varieties
- Apples - Orchard apples often contain interesting wild yeasts and bacteria, and can be chopped and added directly into secondary; do not pasteurize or freeze for maximum microbial potential .
- Apricots - Apricot pits contain a cyanide precursor, though unpitted apricots, and sometimes exclusively the pits (e.g Cascade Noyaux) are used with success in beer. This would suggest that the amount of cyanide in pits is likely low enough to be ok , and that the pits may add a certain character that some brewers desire. If you are concerned about it, then do not use apricot pits. Cantillon reports limiting the contact time of their lambic with apricots for 8 weeks, otherwise the beer becomes too acidic. This may be due to microbes living on the apricot skins and is likely not due to acids in the apricots themselves. Cantillon uses 2/3 pitted and 1/3 unpitted apricots .
- Autumn Olive - This is a shrub producing small tart fruits native to Asia and found naturalized in eastern US (though it is considered invasive).
- Banana - see this MTF thread.
- Black Currants - Finding black currant juice without added sugar can be difficult because of the juice’s high acidity. Keep this in mind when tasting the juice, as the amount of added acidity after refermentation can make the beer unpalatable .
- Blackberries - Adds citric acidity; milder flavor compared to raspberries. Works well mixed with cherries. Can also add a lot of tannin character to a beer .
- Cascara (coffee bean fruit) - see this MTF thread.
- Cherries - Both sweet and sour varieties of cherries are available. Generally sour cherries are used in beer, although sweet cherries have also been used with good results in sour beers. They are more difficult to find and to source some you may need to look into smaller local farmers or frozen or juice options. Varieties of sour cherries include Schaerbeekse (traditional in lambic), Montmorency, Balaton, Morello and Amarelle. The stones also produce some character and can add to the beer, so you may want to consider leaving the pits in with some or all of the fruit. Cherry pits also have a cyanide precursor (see Apricot, above); however given the success of many brewers using whole cherries in beer for decades or more, the levels of cyanide precursor in cherry stones may not be an issue. If you are concerned about it, then remove the stones from cherries when using whole fruit. See Glycosides for more information.
- Cranberries - Consider adding a some raspberries to go with the cranberries for added complexity .
- Elderberries - Avoid using underripe elderberries (and elderberry leaves); they may contain cyanide precursors . Elderberries are very strong flavored . See also WV Elderberries Wine Farm for information on elderberry harvesting.
- Fuyu or American Persimmon - Works well with fruity Brettanomyces character. Allow fruit to get overripe, and then squeeze the fruit to remove from the skins, and press the flesh through a sieve to remove the seeds . American and Fuyu are different species, and can have different qualities. See this MTF thread for general advice on persimmons.
- Grapefruit - Can be combined with zest (as can other citrus fruits). Use 5-10 grams of zest for ~5 gallons. Some prefer pink grapefruit .
- Grapes - Wine grapes are preferable for their depth of flavor compared to table grapes. Consider both the influence of the juice of the fruit as well as the potential to pull tannins and flavor/aroma from skins. Some homebrewers have experimented successfully with blending finished wine with beers, and for many brewers you will have much easier access to good wine than good wine grapes  . If you are interested in sourcing quality grapes and you live in a wine region, make friends with your local wineries. It will probably be good for you even if grape requests do not bear fruit (see what I did there, that was pretty funny).
- Bryan of Sui Generis Blog discusses fermenting with wild North American grapes.
- Funk Factory's "Cervino" and associated MTF thread.
- Winemaker Dara McMains ferments wines with B. anomala, and other cross overs between sour beer and wine.
- Thread on using wine grapes in sour beer, with links to other MTF threads.
- Andrew Zinn from Wicked Weed gives details on how their grape sour beer is produced.
- Jeff Porn of Atom Brewing Company's simple method of removing stems from grapes.
- MTF thread on long contact time on grape skins.
- MTF thread on grape skin contact time, amounts, and avoiding acetic acid production.
- Kiwi - Peel and dice or slice; optionally freeze. Some brewers say leave out skins , but other brewers report success with leaving the skins since the skins are edible. One easy way to remove the skins is to halve the fruit long-ways and then scoop out the fruit, separating it from the skin. See this MTF thread.
- Kumquat - Can get too bitter if too many are used. It doesn't take much to get a nice citrus and rind character .
- Loquot - Leave out pits.
- Lychee - Not much yield when using whole fruit. Difficult to work with because it has a tough rind and large seed. Flavor can be subtle. Recommended to use juice or puree instead of whole fruit .
- Passion fruit - When using whole fruit, use the pulp only. Whole passion fruit can be expensive, so puree or pulp is a good option. Goya Fruta brand has been recommended at 1 package per gallon, and can be found at world markets (Asian and Latino groceries) . Various members of MTF have reported sulfur production when using passion fruit in beer in general.
- Paw Paw - It can be burdensome to remove the flesh from the skins and seeds by hand. MTFer Mark W. recommends using a potato ricer for this .
- Peaches - Some varieties of peaches are prone to bacteria spot, and these varieties are often treated with a copper based solution which can result in a metallic taste in beer. See this Scott Janish blog article.
- Pineapple - Leave the skins out. See also this MTF thread.
- Prickly Pear - Difficult to process. Some advise burning the hairs off and leaving on the skins, however the skins may contribute a slight "pithy" character (some brewers report getting no pithy character by leaving on the skins). Some brewers blend into a puree, and use a food processor to remove the seeds. Others use a press to press out the juice and leave the skins/seeds behind. Others advise to cut them up, add a cup of water, and bring them up to 180°F, and then use a potato masher to mash them up. Hang in a hop sack to drain over night. They are high in pectin and mucilage, so using pectinase to help with clarity is an option (see using pectinase instructions below) .
- Quince - Very aromatic, but also has pectin haze. Also able to be used are Japanese flowering quince (Chaenomeles) . Kristen England recommends using membrillo quince paste; cooking orletting fresh quince get overripte can help remove the high bitterness of the fruit .
- Raspberries - Advice: use a fine-mesh bag for whole fruit or a fine-mesh strainer for puree since seeds/skins may not settle even with extended aging. Frozen products tend to be more consistent than fresh . Raspberries can pair well with both pale and darker sour beers.
- Rose hips - dried forms can just be added without processing. Some recommend to freeze, boil and strain the rose hips (especially if sanitary conditions are required). Although they may not make a large impact on flavor, removing the seeds is recommended for avoiding extra beer loss, and they reportedly become very "gooey" . See also this youtube video on removing the seeds.
- Sea Buckthorn - Adds a lot of acidity; add less to more sour beers. Juicing tends to be the most popular approach. See quantities below .
- Sumac - Provides a lot of "lemony" acidity. Can boil it, but don't boil for too long or the nice red color will turn brown.
- Strawberry - It is thought that the seeds might carry a lot of p-coumaric acid, which can transform into 4-vinylphenol and 4-ethylphenol in the presence of Brettanomyces, which tastes like plastic. Some people have had luck juicing strawberries and removing any seed or vegetal material (or using strawberry juice) to avoid plastic flavors . To remove pulp and seeds, MTF members have advised using a flotte lotte, basket press, or Breville Juice Fountain Elite juicer . There have also been reports that removing the seeds did not remove the plastic phenol with the hypothesis that the strain of Brettanomyces used might play a role . See also this MTF thread. Phillip Emerson of Almanac Brewing Co reported getting no plastic off-flavor when using freeze dried strawberries. He also reported anecdotally that white skin seems to correlate to plastic off-flavors  (~40 minutes in). Several brewers in MTF reported getting no plastic off flavors when using Oregon Fruit strawberry puree .
- Tamarind - Provides an umami flavor that some people might not like .
- Vanilla Fruit (Beans/Extract) - Organic/natural recommended for extract. Start at 1 teaspoon per 5 gallons of beer, and add more to taste. For whole beans, cut long ways and scrape out the insides, add entire bean. Balances well with acidity, and some have reported that it adds some mouthfeel to Brettanomyces based beers .
- Watermelon - Watermelon flavor can be difficult to achieve. Jeffrey Airman of Paradox Brewing Co. uses fresh watermelon with the rind, and supplements with a lot of juice . Steph Cope of CraftHaus Brewing Co used 10 large watermelons/3bbls of kettle soured gose. An immersion blender was used to pulverize; it took a long time for that much watermelon to drop clear, and low yield (but strong watermelon flavor) . Thomas Morley recommends that the watermelon pulp be filtered out to avoid the cloudiness issues (Jester King uses a press ) . James Sites advises juicing the watermelon, then reducing it to remove the water content . Bob Sylvester advises using an "overwhelming amount" of watermelon, and using some of the rind to bolster the flavor .
- Yuzu - Juice form can be very strong. Taste first. Start with 1 ounce per gallon, and add more to taste .
"Contact time" in the table below is for mixed fermentations with Brettanomyces. Kettle sours or beers that do not contain live Brettanomyces can have a much shorter fruit contact time (generally 1-2 weeks). All contact times are assumed to be applied in secondary, and at the end of aging. Keep in mind that this is just a general guideline for usage amounts. Brewers should consider their base beer's characteristics such as abv, flavor profile, acidity levels, etc. when considering how much fruit to add. It is common for lambic brewers to age much higher fruit to beer ratios and then blend back with unfruited lambic to the desired g/L amount. If you are really trying to nail the perfect fruit amount, applying this sort of technique could be useful (assuming you have suitable beers around to blend back). This will allow you to try different blend ratios to determine the appropriate amount of fruit for your beer and desired outcome. In regard to fruit ratios, Belgians calculate fruit ratios by : Fruit ratio (g/l) = (KG of Fruit / (KG of fruit + liters of beer))*1000 . Fruit displacement isn't a huge concern; 10 pounds of fruit generally requires an extra gallon of headspace or 1200 grams of fruit requires around one liter of headspace (the exact volume depends on the volume of the fruit ). However, the fruit will usually re-ferment, causing a blow off, so allowing 10-20% of the total volume for extra headspace is a good idea. This site might assist with calculating the displacement volume of fruit. Maintain a temperature range from 65-75°F (18-24°C) during the fermentation of the fruit if possible, however, temperature swings during fruit fermentation are generally more forgivable than when temperatures swing during primary fermentation.
Fruit can be used for a 2nd steeping and second use of fruit can still provide flavor and color, but in a more subdued way than first use. Both Jester King and the Rare Barrel use fruit more than once, and Jester King reports preferring their second use fruit beers to their first due to more subtlety and balance (~15 minutes in). Other breweries, including Cantillon, The Bruery, and Upright, also report multiple conducting steepings of fruit, at least at one point if not currently.
Jay Goodwin from The Rare Barrel suggests using 42 lbs/oak barrel (0.7 lbs/gallon) as a good starting point for fruit puree  (~22 minutes in). See also the Sour Hour Episode 70 with Breakside for a brief discussion of fruiting ranges, highlighting the wide range of ratios used and the importance of fruit variety and quality (~47 min in).
Don't be afraid to experiment outside of these guidelines.
- Click here and comment on the MTF thread to add your recommendations to this wiki!
- Click here to convert pounds per gallon to grams per liter.
|Fruit||Juice||Concentrate||Purée||Dried||Whole||Contact Time||Commercial Examples|
|Apple||0.5 lb/gal ||1-2 lb/gal ||6-8 weeks|
|Apricot||0.75 lbs/gal (~56 minutes in)||1-2.5 lbs/gal||6-8 weeks||300 g/l (2.5 lbs/gal) Cantillon Fou Foune - 2/3 pits, 1/3 unpitted - max 8 weeks contact time |
|Autumn Olive (Autumn Fruit)||1-1.5 lbs/gal ||2 lbs/gal ||6-8 weeks|
|Blackcurrant||24-36 fl oz/gal ||14oz - 20 oz of CurrantC™ concentrate for 5 gallons of beer ||3 weeks juice/6-8 weeks whole|
|Blackberry||0.7-3 lbs/gal ||6-8 weeks||350 g/l (2.9 lb/gal) Tilquin Mure|
|Blueberry||2-3 lbs/gal||6-8 weeks|
|Cantaloupe||0.5 lb/gal ||6-8 weeks|
|Cascara||~1 oz/gal ||3 days|
|Cherry (tart or sweet)||12-24 fl oz/gal||4-8 fl oz/gal ||2+ lb/gal ||0.5-1.5 lbs/gal ||1-3.3 lbs/gal||3 weeks juice/6-8 weeks whole . Lambic brewers/blenders sometimes age longer (6-12 months)||200 g/l (1.67 lbs/gal) Cantillon Kriek, 300 g/l (2.5 lbs/gal) Cantillon Lou Pepe Kriek, Oud Beersel Oude Kriek, 400 g/l (3.33 lb/gal)|
|Clementine||1 lb/gal ||5 weeks |
|Cranberry||32 fl oz/5 gal ||1 lb/gal ||6-8 weeks|
|Elderberry||0.5 lbs/gal ||6-8 weeks|
|Fig||0.25 lbs/gal||1-2 lbs/gal (cooked or caramelized) ||4 weeks||Allagash Bijoux (2 lbs per gallon)|
|Fuyu Persimmon||2.5 lbs/gal ||12 weeks |
|Goldenberry (ground cherry)||2 lbs/gal for subtle flavor, 4-5 lbs/gal for strong flavor ||6-8 weeks|
|Grape (Wine)||2-3 lbs/gallon||300 g/l (2.5 lbs/gal) Cantillon St. Lamvinus and Vigneronne|
|Grapefruit||3.5-5.5 fl oz/gal |
|Guava||1-2 lbs/gal ||6-8 weeks|
|Honeydew melon||2-3 lbs/gal ||4 lbs/gal ||3-4 weeks|
|Key Lime||100mL/gal ||Added as priming sugar at bottling|
|Kiwi||2 lbs/gal ||6-8 weeks|
|Kumquat||0.25-0.60 lbs/gal ||6-8 weeks|
|Loquat||2 lbs/gal||6-8 weeks|
|Mango||18 fl oz / gal  (note that this resulted in significant loss of beer volume); 2 lbs/gal. 0.6 lbs/gal for entire fruit (pit, peel, etc.) ||6-8 weeks|
|Nectarine||1-2 lbs/gal||6-8 weeks|
|Olallieberries||3 pounds per gallon (maybe on the higher side but good) ||2 months |
|Passion Fruit||250-500mL per 5 gal ||0.5-1.0 lb/gal ||0.5-1 lbs/gal ||6-8 weeks|
|Paw Paw (pawpaw)||>1 lb/gal (flesh only) ||> 2 weeks (at ~1lb/gal)|
|Peach||0.5-2 lb/gal ||1-2 lbs/gal||6-8 weeks|
|Persian Lime (loomi/dried lime/black lime)||~1 lime per gallon, or less ||One quarter added during boil, rest added to secondary for 6-8 weeks (or all added to late boil, or all added to secondary)||Upright Brewing Saison Vert.|
|Pineapple||1.36 - 2 litres per 20 litres of beer (Dole sugarless)||2 lbs/gal (skins on)||1 pineapple/gal ||6-8 weeks|
|Plum||2-3 lbs/gal||Some prefer shorter contact (1-2 weeks) and higher rate, others suggest longer contact (3+ months) and lower fruiting rates||250g/l (2 lbs/gallon) Tilquin Quetsche (contact time of 4 months)|
|Pomegranate||8-13 fl oz/gal ||6-8 weeks|
|Prickly Pear||0.5 lb/gal ||6-8 weeks|
|Quince||2 lb/gal ||6-8 weeks|
|Raspberry||1-2.5 lbs/gal||6-8 weeks||200 g/l (1.67 lbs/gal) Cantillon Rose de Gambrinus, 300 g/l (2.5 lbs/gal) Cantillon Lou Pepe Framboise|
|Rhubarb||0.5-1.0 lb/gal ||6-8 weeks|
|Rose Hips||2oz/5gal (flameout) ||bottling time (secondary)|
|Salmonberries||1 lbs/gal ||6-8 weeks|
|Sea Buckthorn||2-8 grams/liter of fruit before juicing ||6-8 weeks|
|Strawberry||0.5-1 lbs/gal ||2-3 lbs/gal||6-8 weeks|
|Strawberry Guava||3 lbs/gal (blend down if needed) ||6-8 weeks||Lanikai Brewing Company's Forever Summer. Strawberry guava is added on hot side when other fruits are used, or cold side when not. Remove seeds and skin .|
|Vanilla Fruit (Beans) ||(Extract) 2 teaspoons/5 gal||(Whole pods) 1/2-2 beans per 5 gal||Rare Barrel Home Sour Home|
|Watermelon||40-64 fl oz/gal ||6-8 weeks||Jester King Hibernal Dichotomous (12% watermelon juice ), and another beer rumored to use 30% fresh watermelon juice .|
|Yuzu (citrus)||1-5 oz/5gal ||~2 lbs/5 gal ||Added at packaging|
|Zante Currant||5-10 fl oz/gal||0.2-0.4 lbs/gal||4-8 months |
(In Progress) Once your fruit beer has reached the character you desire, you will want to remove the beer to a packaging/further aging vessel or to a final package while leaving the fruit behind. Depending on the type and form of fruit you used, this can be a challenging task. Juices should not present a problem and purees will generally settle out. Larger chunks or whole fruits (fresh, frozen, or dried) may be more easily avoidable however some fruits, such as raspberries, tend to disintegrate and can be especially troublesome. Link to this MTF post
Filtering and Removing Haze
Over time, most beer will clear eventually. However, there are methods for clearing fruited beer quicker and perhaps to a greater degree than natural conditioning.
Some types of fruit and/or brewing systems may require filtering. One option is to use a filter, such as a GW Kent Lenticular Filter Housing, a steel housing bag filter (see also this bag filter from GW Kent), or an inline filter. If a filter like this is going to be used as the primary filter, it is advised to use two that can be split off so that one can be cleaned while the other continues to run (see this MTF thread showing Casey Brewing's setup). Brandon Jones of Yazoo Brewing Co. uses a stainless steel scrubby secured by a stainless worm clamp on the end of a bulldog for racking fruited beer (only good for a few barrels; he recommends a more robust filter for larger operations) . Marek Mahut extended this idea by putting the scrubby into the site glass . Chad Ramey adapted this method for the homebrew scale using a homebrew-sized stainless racking cane. Fruit can also be bagged in a mesh bag to help with filtering. Gabe Slagle reported good results with fitting a homebrew-sized mash tun false bottom lined with a gasket into the bottom of his conical fermenters as a way to filter fruit, with the only downside being that he has to shovel the fruit out through the manway (he also recommeneded using an inline filter to catch smaller debree).
On a homebrew level, using any system that is designed to filter dry hops from the fermenter should also work for filtering fruit. Examples include using a fine mesh bag on either the receiving or exiting end of a siphon, using a 300 micron stainless steel "Dry Hopper for Glass Carboys" which fits over the receiving end of most homebrew auto-siphons, or a corny keg dip tube screen (also fits on steel racking canes ). Filtering may not remove haze from pectin. Some brewers believe that pectinase can help with getting the fruit to separate from the beer . Fruit can also be bagged in a mesh bag to help with filtering if the fermenter's opening is wide enough to accomidate it (non-carboy shaped fermenters).
- Nate Ferguson's guide to filters for commercial brewers (pending an actual write up for the wiki).
- MTF thread on designing fruiting tanks with filters/false bottoms.
Different types of fruit contain differing levels of pectin, which cause haze. One option, and perhaps the preferred option for both commercial and homebrewers, is to use pectic enzyme (more formally called pectinase). Pectic enzyme is available from brewing supply retailers and is available in both powdered and liquid format. The liquid format tends to be easier to use, and requires less of it to work. Add the pectic enzyme when adding the fruit (before re-fermentation of the fruit) if possible, but the pectic enzyme can be added after the fruit ferments as well. Pectic enzyme is sensitive to ethyl alcohol, so a 50-100% increase in the dosage that the manufacturer recommends may be needed when adding it to an alcoholic beverage. Using this much pectic enzyme should not contribute a flavor difference or impact the health safety of the beer. The beer should clear in a matter of weeks at the most . Some brewers believe that the use of pectinase also helps improve the quality of the fruit flavor .
Another option is to try to use BSG Biofine® Clear after the beer has fully extracted the fruit. Be sure to cold crash the beer down as close to 0°C as possible when using this product. Use a higher dosage if the beer is not clarifying. This product should produce clear beer in most circumstances, however, there have been reports of it not clearing up pectic haze .
Additional Articles on MTF Wiki
- Table of fruits with starting gravities, TA, pH, and tannin.
- Phenol Explorer website for various foods.
- Approximate pH of some fruits and vegetables.
- Shaun Hill's advise on using International Citrus Units to measure fruit additions.
- Beer and Wine Journal Table of Fruits with water, sugar, and acid percentage.
- Another table of water and sugar percentages of various fruits.
- Brix readings of different fruits.
- Food Volume to Weight Conversions (assisting with determining volume displacement of fruit).
- Tips from Chad Yakobson of Crooked Stave, Walt Dickinson of Wicked Weed, and Jeffrey Stuffings of Jester King.
- MTF Thread on adding wine to beer (homebrew).
- "Punch Down Beer", blog article on Funk Factory Guezeria on fruiting in an upright barrel and punching down the fruit.
- "A Guide to Blending Sour Beer With Fruit" by Matt Miller; includes ABV and TA calculators for fruit additions.
- Gordon Strong's article on which category to enter fruited "Berliner Weisse", "lambic", and sour beers into BJCP competitions.
- TTB Approval Formulation wizard.
- Raf Soef. Milk The Funk Facebook group. 04/08/2017.
- "Framboise de Amorosa". The Lost Abbey website. Retrieved 07/26/2017.
- Displacement (fluid). Wikipedia. Retrieved 05/05/2016.
- The Sour Hour #14: with Jester King, pt. 1
- Raf Soef's tea strainer modification
- Conversation with Raf Soef on MTF regarding re-fermentation of fruit and dealing with blow off. 11/30/2015.
- MTF facebook thread about fruit caps
- Ben Rotter. "Fruit Data: Yield, Sugar, Acidity, Tannin". Improved Winemaking website. 2011. Retrieved 03/16/2018.
- Conversation with Kyle Kohlmorgen on MTF regarding fruit. 10/23/2015.
- Thoughts from Raf Soef on using whole fruit in a MTF thread
- "Effects of freezing and thawing on texture, microstructure and cell wall composition changes in papaya tissues." Phothiset S, Charoenrein S. 2014.
- Conversation about freezing fruit on MTF. 05/10/2016.
- Conversation with Devin Bell on MTF. 01/17/2016.
- Conversation with Dara McMains on MTF regarding puree. 11/1/2015.
- Conversation with Ehren Schmidt about Perfect Purees having cane sugar and acids added to them on MTF. 05/18/2016.
- Adi mango pulp discussion
- Pomegranate Margarita Gose. Ale of the Riverwards Blog. Ed Coffey. 11/13/2015. Retrieved 11/19/2015.
- MTF Thread on Lakewood Juice. 03/07/2016.
- René Redzepi and David Zilber. "Lacto Blueberries". The Splendid Table blog. Excerpted from The Noma Guide to Fermentation. 2018. Retrieved 05/18/2019.
- Dr. Bryan Heit. Private correspondence with Dan Pixley. 05/18/2019.]
- "The Noma Guide to Fermentation". René Redzepi and David Zilber. Workman Publishing. October 16th, 2018.
- Jeffrey Airman. The Mead House Episode 109. Retrieved 05/18/2019.
- Conversation with Aiden Robert Jönsson regarding using apples on MTF. 06/01/2016.
- MTF conversation about cyanide in stones
- Private conversation between Jean Van Roy and Richard Sigesmund.
- Conversation on MTF about adding fruit to sour beer. 10/23/2015.
- Thread on MTF regarding blackberries and tannins. 08/16/2016.
- Conversation with Dustin Carver on MTF for cranberry usage. 11/16/2015.
- "Searching for cyanide". Nordic Food Lab. 09/05/2013. Retrieved 07/27/2016.
- Mike Karnowski and Josh Hockley. Milk The Funk Facebook group post on elderberry usage. 09/24/2017.
- DeWayne Schaaf. MTF thread on persimmons. 11/17/2017.
- Conversation with Derek Springer, Murray Sharp, Steve Holat, Brandon Jones, and Dara McMains on MTF. 01/21/2016.
- Mad Fermentationist blending wine and lambic
- Mad Fermentationist New Zealand saison
- Conversation about lychee fruit on MTF. 04/14/2016.
- Passion fruit recommendation from Alex Aguillon. 11/13/2016.
- Paw Paw discussion on MTF FB page
- Conversation on MTF on prickly pear fruit. 02/20/2017.
- Conversation about prickly pear fruit on MTF. 09/17/2016.
- Kristen England. Milk The Funk Facebook thread on using quince. 05/08/2018.
- Bjarte Nataas. MilkThe Funk post on preparing rose hips. 09/09/2017.
- MTF tips by Brett Ellis and Stephen Andrews on Sea Buckthorn usage. 08/29/2017.
- Discussion with James Sites on MTF regarding strawberries and 4EP precursor. 05/09/2016.
- Conversation with Kyle Pittser on MTF regarding the use of strawberries. 03/01/2017.
- Ingo Janssen, Thomas Creighton, and Ryan Adam Bickley. Milk The Funk Facebook group. 03/24/2017.
- Tim Moriarty and Justin Amaral. Milk The Funk Facebook group post on removing seeds from strawberries. 02/15/2018.
- Phillip Emerson. The Sour Hour Podcast, episode #119. 02/14/2020.
- Several MTF members on using Oregon Fruit strawberry puree. Milk The Funk Facebook group thread. 05/25/2020.
- MTF thread recommendations by Nathan Peck, James Sites, Justin Amaral, Dustin Carver, and Rodney Beagle. 12/8/2016.
- Milk The Funk Facebook thread on vanilla beans. 03/05/2017.
- Conversation with Jeffrey Airman on watermelon use. 06/03/2016.
- Conversation with Steph Cope on watermelon usage. 06/03/2016.
- "Introducing Jester King Hibernal Dichotomous". Jester King's Blog. Retrieved 11/13/2016.
- Conversation with Thomas Morley about watermelon usage. 11/12/2016.
- Conversation with James Sites on watermelon usage. 05/06/2016.
- Sylvester, Bob. Milk The Funk Facebook group. 03/31/2017.
- Conversation with Matt Bing and Dennis Lovelock on MTF. 01/28/2016.
- MTF Facebook comment from Raf about fruiting ratios
- Sour Hour episode 15 - Jester King pt. 2
- Cantillon Kriek
- Upright Special Herbs
- The Sour Hour episode 10
- The Sour Hour episode 70
- Brian stephens. MTF Thread on fruit usage for black currants concentrate. 02/20/2019.
- Steve R on MTF facebook page
- Steve Brockman. Milk The Funk Facebook thread on cascara usage. 09/06/2018.
- Zinn, Andrew. Milk The Funk Facebook group. 03/26/2017.
- MTF Thread by Eccentric Beekeeper on using dried cherries. 01/16/2016.
- Conversation with James Sites on cranberry juice on MTF. 11/17/2015.
- Various MTF members. Milk The Funk Facebook thread on figs. 05/08/2018.
- Justin Amaral. Milk The Funk Facebook thread about goldenberry amounts. 02/04/2018.
- Joshua Martinez, Sam Bates, John Rowley and Nathan Rice . Milk The Funk Facebook group thread on honeydew melon usage. 10/26/2018.
- Conversation with Richard Preiss on MTF regarding key lime juice. 01/21/2016.
- Kyle B Pearce. MTF thread on using mango. 02/20/2019.
- MTF_Thread by Trey Rabinek
- MTF follow up by Trey Rabinek
- Conversation about passion fruit concentrate on MTF. 11/11/2016.
- Steve Haumschild, Neil Caron, and John Rowley. Milk The Funk Facebook thread on passionfruit puree. 04/18/2018.
- Conversation with Allen Stone on passion fruit usage. 11/12/2016.
- Conversation with Manny Jannes and Kristopher Johnson (Green Bench brewer) on passion fruit additions on MTF. 10/22/2015.
- MTF Paw Paw thread from 8-Sept-2016
- Conversation with Caroline Whalen Taggart on MTF regarding Persian limes. 12/06/2016.
- Tips from various brewers on using black lime on MTF. 05/07/2017.
- Richard Sigesmund. Private correspondence with Dan Pixley. 10/06/2020.
- Lars Meiner. Milk The Funk Facebook group post about pineapple usage. 06/06/2021.
- MTF thread about plums, 14-Sept-2016
- Tilquin Facebook Post 22-Sept-15
- Ale of the Riverwards Blog by Ed Coffey, Pomegranate Margarita Gose. 11/13/2015.
- Mitch Ermatinger, Brian King, Matt Kent. Milk The Funk Facebook group post. 06/08/2017.
- Tim Borket. Milk The Funk post on rose hips usage. 09/06/2017.
- MTF thread by Kyle Hammock. 01/15/2016.
- Steve Haumschild on strawberry guava usage. Milk The Funk. 09/04/2017.
- Conversation with Doug Stallard on MTF. 05/17/2016.
- Russian River Consecration Description. Retrieved 10/21/2015.
- Brandon Jones. Milk The Funk Facebook thread on filtering beer out of barrels. 07/11/2017.
- Marek Mahut. Milk The Funk Facebook thread on filtering fruit from beer. 08/31/2018.
- Matthew Smylie. Thread on MTF about filtering fruit. 09/08/2017.
- Conversation with Alex Loijos and James Sites on pectinase usage. 08/17/2016.
- Conversation with James Sites and Nick Moench on MTF. 04/15/2016.
- Conversation with Ehren Schmidt and Daniel Addey Jibb on MTF. 04/16/2016.