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'''Funky mixed fermentationsBrettanomyces and Saccharomyces Co-fermentation''', for the purposes of this article, refer is a type of [[Mixed Fermentation|mixed fermentation]] that specifically refers to fermentations that contain ''[[Saccharomyces]] '' and ''[[Brettanomyces]]''. They do not contain significant amounts of [[Lactic_Acid|lactic acid]] produced by lactic acid bacteria such as (''[[Lactobacillus]] '' and ''[[Pediococcus]]''). As such, these beers may have a lightly tart flavorfrom [[Acetic_Acid|acetic acid]] production by ''[[Brettanomyces]]'', but are generally not described as being ''sour'' if properly brewed (see the [[Mixed Fermentation]] pagefor mixed fermentation sour beers). The flavor of beers fermented with ''Saccharomyces'' (generally ale yeast, but they can also be fermented with lager yeast) and ''funkyBrettanomyces'' beers is often dominated by the array of flavor compounds produced by ''[[Brettanomyces]] (see [['', unless the beer is young in which case the ester and phenol profile of the fermenting strain of ''Saccharomyces'' might still have an impact on the flavor. In the case of young beers, the flavor profile will begin to be changed by ''Brettanomyces#Brettanomyces_Metabolism|Brettanomyces metabolism]])'' as esters, phenols, and fatty acids are created and metabolized. Generically speaking, these flavors almost always consist of both fruity esters and phenolic components. Sometimes they also consist of an array of other flavors that are generically described as "funky". Specifically, fruity esters range from tropical fruits, to stone fruits to citrus fruits, smoke, and are produced by all strains of ''barnyard animal funkBrettanomyces''to some degree. Phenols, fatty acids, alcohols, aldehydes, bitterness that lingers on the palate longer than hop bitterness and is accompanied by undertones other compounds can also create a wide range of fruitflavors including smoke, "barnyard animal", ''horse blanket'', sweat, body odor, rancid cheese, etc. For more information on the identification of these compounds and the known conditions that impact their production, see [[Brettanomyces#Brettanomyces_Metabolism|''Brettanomyces'' metabolism]]. For 100% ''Brettanomyces'' beers, see [[100%25_Brettanomyces_Fermentation|100% ''Brettanomyces'' Fermentation]].
==Brewing Methods==
<!-- Removing graph for now due to out of date information[[File:Funky_Ferm.jpg|thumb|upright=2.5|Conceptual graph of traditional microbe and wort dynamics|Conceptual graph of dynamics of funk expression and inoculation timing of Brettanomyces. Y-axis for each microbe group depicts relative activity which combines in a conceptual sense: growth, attenuation , and production of flavor compounds. Plot was drawn by Drew Wham based on concepts discussed in American Sour Beer <ref> Tonsmeire, M. (2014). American Sour Beers. Brewers Publications </ref> . See the table to the left for updated information on where this graph may no longer be accurate. ]]-->
{| class="wikitable sortable"
! Technique !! More Funk !! Less Funk !! Note
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| Inoculation timing || After ''Saccharomyces '' has finished fermentation || At the start of Fermentation || See figure 1The timing of the ''Brettanomyces'' pitch may not have a significant effect a lot of the time; pending data from George Van Der Merwe or another source of scientific data <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2103639509664252/?comment_id=2117621214932748&comment_tracking=%7B%22tn%22%3A%22R%22%7D Richard Preiss. Milk The Funk Facebook thread on co-pitching versus subsequent pitching of ''Brettanomyces''. 06/04/2018.]</ref>.
|-
| ''Brettanomyces '' Inoculation cell count || Lower cell count or higher cell count || Higher cell count or lower cell count|| Pitching Although more data is needed, pitching rate of ''Brettanomyces'' in secondary appears to may not have no a measured impact on beer flavor. See [[Brettanomyces secondary fermentation experiment]].
|-
| Strain of ''Saccharomyces '' || Phenol positive strain || Phenol negative strain || PofPOF+ strains of ''S. cerevisiae '' form 4-vinylguaiacol by enzymatic decarboxylation of ferulic acid <ref> Coghe, S., Benoot, K., Delvaux, F., Vanderhaegen, B., & Delvaux, F. R. (2004). Ferulic acid release and 4-vinylguaiacol formation during brewing and fermentation: indications for feruloyl esterase activity in Saccharomyces cerevisiae. Journal of Agricultural and Food Chemistry, 52(3), 602-608.</ref> . More recent data suggests that POF+ strains of ''Saccharomyces'' are not necessary for ''Brettanomyces'' to create phenols because ''Brettanomyces'' can create the precursor 4-vinyl phenols on its own as long as ferulic acid and other grain derived precursors are available <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1585065488188326/?comment_id=1585068344854707&reply_comment_id=1585072311520977&comment_tracking=%7B%22tn%22%3A%22R3%22%7D Conversation with Richard Preiss on MTF. 02/16/2017.]</ref>. See [[Brettanomyces secondary fermentation experiment]] and [https://www.themadfermentationist.com/2014/09/phenols-and-brett-fruity-and-funky.html?m=1 this The Mad Fermentationist blog article].
|-
| Ferulic Acid (malt derived) || More Ferulic Acid || Less Ferulic Acid || A precursor of 4-vinylguaiacol. Perform a [http://braukaiser.com/blog/blog/2010/06/04/how-much-effect-does-a-ferulic-acid-rest-have/ ferulic acid rest], and use around 70% barley malt and 30% wheat malt for the highest ferulic acid extraction (see [[Brettanomyces#Phenol_Production|''Brettanomyces'' phenol production]] for more information).
|-
| Time since Inoculation || Aged Beer || Young Beer||
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| Fermentation Temperature || Higher temperature increases esters in some but not all strains of ''B. bruxellensis''. || Lower temperature decreases esters in some but not all strains of ''B. bruxellensis''. || Temperature does not appear to significantly affect the amount of phenol compounds produced by ''B. bruxellensis'' in a 100% ''Brettanomyces'' fermentation. Therefore, the perception of a more "funky" beer might depend on producing less esters rather than creating more phenols. See [[Brettanomyces#Phenol_Production|''Brettanomyces'' phenols]] and [[100%25_Brettanomyces_Fermentation#Are_100.25_Brett_Beers_Really_Cleaner.3F|100% ''Brettanomyces'' Fermentation]] for more information.
|}
==Finishing Funky Mixed Fermentations==Aging and Packaging===Bottling In general, beers brewed with ''Saccharomyces'' and Kegging===''Brettanomyces'' tend to lead to a slow fermentation by the ''Brettanomyces'', which can hyper-attenuate the beer over time (see [[Brettanomyces#Carbohydrate_Metabolism_and_Fermentation_Temperature|''Brettanomyces'' carbohydrate metabolism]]. These beers are often aged for at least 3-4 months to wait for a stable final gravity before packaging. However, they can also be aged for longer which helps develop flavors produced by the ''Brettanomyces''. Due to the potential for acetic acid development when exposed to oxygen over time, care should be taken when aging any beer with living ''Brettanomyces'' (see [[Mixed_Fermentation#Aging|mixed fermentation aging]]). See the [[Packaging]] pagefor instructions on determining when it is safe to package a ''Brettanomyces'' and ''Saccharomyces'' Co-fermentation, and tips on how to package it.
===Dosing Clean Beer with ''Brettanomyces'' At Bottling===
One method that some brewers attempt is adding a small pitch of ''Brettanomyces'' to a clean beer at bottling time. This can be done either in the bottling bucket/tank, or added to each bottle individually. If adding ''Brettanomyces'' to each bottle individually, a 1 mL dosage of ''Brettanomyces'' from a starter should be enough since pitching rate seems to have little impact on the beer <ref>[[Brettanomyces_secondary_fermentation_experiment]]</ref>. Some brewers believe that adding the ''Brettanomyces'' at bottling time results in a more complex beer. It is speculated that the extra stress of pressure within the bottles helps to create this complexity, although evidence for this is lacking. Other stressors such as lack of oxygen are also speculated to have an impact. One challenge with this approach is that it is difficult to predict how much ''Brettanomyces'' will further attenuate the beer once in the bottle. Over-carbonation and bottle bombs can easily be an issue with this method if the brewer is not careful. Each degree Plato adds ~2 volumes of CO2 <ref>[http://braukaiser.com/wiki/index.php/Accurately_Calculating_Sugar_Additions_for_Carbonation#Remaining_or_Residual_Extract "Accurately Calculating Sugar Additions for Carbonation." Kai Troester. Braukaiser.com. Retrieved 08/07/2016.]</ref>. Since different species and strains of ''Brettanomyces'' ferment different types of sugars, some strains might be safer for dosing at bottling time. For example, most strains of ''B. anomulus'' do not ferment maltose, which is around 50% of sugar in wort, so this makes it a good choice for adding to the beer at bottling. However, if the amount of additional attenuation is already known for a particular beer and a particular strain of ''Brettanomyces'' , than any strain can be used. Daniel Addey-Jibb, co-owner and brewer at Le Castor near Montreal, Quebec advises that the approach that his brewery takes is to ferment their saison wort down to 1°P. Once at 1°P , the beer is cold crashed, fined, and then bottled with ''Brettanomyces''. The beer is then stored at room temperature for three months to condition naturally in the bottle. During bottling conditioning, their ''Brettanomyces'' culture takes the beer down below 0°P, and their desired level of carbonation is reached. This process took Addey-Jibb's team dozens of trials to perfect using their specific wort recipe, saison yeast, and ''Brettanomyces'' strain. Different species or strains of ''Brettanomyces'' might ferment differently, and different wort compositions might also ferment differently. For example, Addey-Jibb's saison is mashed with malted barley, wheat, and rye at a low temperature so there are not many higher chain sugars, allowing the beer to dry out quickly <ref>[http://www.thebrewingnetwork.com/session-le-castor/ Addey-Jibb, Daniel. Interview on the Brewing Network's Session podcast. 10/04/2016.]</ref>. Other wort compositions that include higher chain sugars from specialty malts and/or higher mashing temperatures might ferment much slower, and thus knowing what the final gravity will be once ''Brettanomyces'' is added is difficult to know without running trials on that specific fermentation profile. It is recommended to use Belgian beer bottles helps of sparkling wine bottles that can withstand higher pressures than regular beer bottles just in case over-carbonation becomes an issue. A "forced fermentation test" might help to determine the final gravity of a given ''Brettanomyces'' strain or blend of strains. Use the same wort composition as the beer in question, and pitch a large cell count of ''Brettanomyces''. Use a stirplate if possible, and an airlock to create keep oxygen out (some ''Brettanomyces'' strains can attenuate further when fermented aerobically and thus will not give an accurate final gravity reading when fermented aerobically). Keep the temperature around 80-85°F for a month or two, and then measure the gravity. Each gravity point gives produces about 0.5 volumes of CO2. Adjust the priming sugar for the rest of the batch accordingly. Use bottles that are rated for higher pressures, such as Belgian bottles or sparkling wine bottles <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1536542119707330/?comment_id=1537256646302544&reply_comment_id=1537384512956424&comment_tracking=%7B%22tn%22%3A%22R0%22%7D Conversation with Adi Hastings on MTF regarding forced fermentation tests with ''Brettanomyces''. 1/2/2017.]</ref>. For more information on bottling sour and funky beer in general, see the [[Packaging]] page. ==Effects of ''Brettanomyces'' Pitching Rate=====Review of Scientific Analysis===The published analysis of beer that is co-fermented with ''S. cerevisiae'' and ''Brettanomyces'' is rare. In this section, published data on this complexitytopic will be reviewed. [https://www.facebook.com/groups/MilkTheFunk/permalink/1935201276508077/ Nick Mader of Fremont Brewing (2017 Master Brewers Conference Presentation)] compared various flavor compounds produced between a 100% ''S. cerevisiae'' (BSI-565, Wallionian Saison yeast) and 100% ''B. bruxellensis'' (BSI-Drei), and percentage combinations of 75/25, 50/50, and 25/75 inoculations of the BSI-565 strain and BSI-Drei strain. Fermentations were completed in 35 days, and the beers were analyzed for their ester and phenol content. Attenuation results were about the same for the 100% BSI-565 and the co-fermentation of BSI-565 and BSI-Drei, while the attenuation rate was around 12% lower for the 100% BSI-Drei fermentation, indicating that co-fermentation with these two particular strains did not greatly affect attenuation and that the BSI-Drei did not ferment as well by itself. The esters that were analyzed were ethyl acetate (pineapple, pear, solventy), ethyl butyrate (tropical fruit), ethyl hexanoate (apple), ethyl decanoate (apple, brandy), ethyl octanoate (waxy, pineapple), isoamyl acetate (banana), isobutyl alcohol (solventy), and isoamyl alcohol (fusel, banana). Ethyl acetate had the most sporadic results. It was highest in the 100% BSI-565 fermentation (43 ppm; above the 33 ppm odor threshold), and lowest in the 100% BSI-Drei fermentation (21 ppm; below the 33 ppm odor threshold), but when co-fermented the ethyl acetate production rates formed a pattern of more ethyl acetate as the pitching rate of BSI-565 was decreased and the pitching rate of BSI-Drei was increased. The 75/25 ratio produced 27 ppm of ethyl acetate, 50/50 produced 34 ppm, and the 25/75 produced 42 ppm (BSI-565 to BSI-Drei ratio in percent pitching rate). The highest ethyl acetate concentrations were therefore for the 100% BSI-565 and the 25%/75% BSI-565 to BSI-Drei.
==See Also==
===Additional Articles on MTF Wiki===
* [[100%25_Brettanomyces_Fermentation|100% ''Brettanomyces'' Fermentation]]
* [[Mixed Fermentation]]
* [[Brettanomyces]]
* [[Saccharomyces]]
* [[Brettanomyces secondary fermentation experiment]]
===External Resources=== * [https://www.whitelabs.com/sites/default/files/belgianchart_0.pdf White Labs list of Belgian yeast strains and characteristics, including phenols/spiciness.]* [https://beerandbrewing.com/podcast-episode-253-matt-van-wyk-and-brian-coombs-of-alesong-brewing-and-blending/ Craft Beer & Brewing Podcast Episode 253: Matt Van Wyk and Brian Coombs of Alesong (52 mins in).]
==References==
<references/>
[[Category:Techniques]]