Changes

<!-- Removing graph for now due to out of date information[[File:Funky_Ferm.jpg|thumb|upright=2.5|Conceptual graph of traditional microbe and wort dynamics|Conceptual graph of dynamics of funk expression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. ]]-->

| 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>.

| Strain of ''Saccharomyces'' || Phenol positive strain || Phenol negative strain || POF+ 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 percursors 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 grains that contain more around 70% barley malt and 30% wheat malt for the highest ferulic acid such as wheatextraction (see [[Brettanomyces#Phenol_Production|''Brettanomyces'' phenol production]] for more information).

| 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.

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.

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>. 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 of sparkling wine bottles that can withstand higher pressures than regular beer bottles just in case over-carbonation becomes an issue.

==Effects of ''Brettanomyces'' Pitching Rate=====Review of Scientific Analysis===

[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. Ethyl butyrate was highest in the 100% BSI-565, and curved downward as the pitching rate for the BSI-565 strain was decreased. Ethyl butyrate was below the odor threshold in the 100% BSI-Drei fermentation. This indicates that the production of ethyl butyrate was dependent on the pitching rate of BSI-565, and that the BSI-Drei strain did not produce significant amounts of this ester. For each of the esters ethyl hexanoate, ethyl decanoate, ethyl octanoate, they had a slight decrease as the pitching rate of BSI-565 decreased, indicating that these esters are produced more by the BSI-565 strain; however, the small measured differences may not be reflected in the actual taste/aroma of the beers since the differences were so small. The exception was ethyl decanoate which was around 3x higher in the 100% BSI-Drei, which indicates that ethyl decanoate is a major flavor contributor to 100% BSI-Drei fermentations. Overall, the ester concentrations were significantly lower in the BSI-565/BSI-Drei fermentations compared to the strains of ''S. cerevisiae'' and ''B. bruxellensis'' used by [[Brettanomyces_secondary_fermentation_experiment|Lance Shaner and Richard Preiss in their similar experiment]], indicating that total ester concentrations are highly dependent on the strains used. Isoamyl acetate, which was above odor threshold in the 100% BSI-565 fermentation, was almost not detectable in any of the fermentations that contained BSI-Drei (it was 0 ppm in the 100% BSI-Drei fermentation), which is in agreement with other studies that ''Brettanomyces'' hydrolyzes this ester. The alcohols isobutyl alcohol and isoamyl alcohol were slightly decreased as the pitching rate of BSI-565 decreased, and were extremely low in the 100% BSI-Drei, indicating that these alcohols were produced more so by BSI-565. The phenols that were measured in Mader's experiment were 4-vinylguaiacol (clove), 4-ethylguaiacol (smokey, spicy), and 4-ethylphenol (medicinal, barnyard). While the 100% BSI-565 fermentation had high levels of 4-VG (1800 ppm), they were less than half the amount in the co-fermented ferments (600-800 ppm) but still above odor threshold (300 ppm) (the different ratios of BSI-565 to BSI-Drei did not have a large impact), and 4-VG was below threshold in the 100% BSI-Drei fermentation. 4-EG and 4-EP had high levels in the co-fermentations with BSI-565 and BSI-Drei and the 100% BSI-Drei, and the ratios did not have a large impact. This is in agreement with another experiment by [[Brettanomyces_secondary_fermentation_experiment|Lance Shaner and Richard Preiss]] that showed that pitching rate of ''Brettanomyces'' after fermentation with ''S. cerevisiae'' did not have a great effect on the levels of phenols produced <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1935201276508077/ Nick Mader. 2017 Master Brewers Conference Presentation. 2017.]</ref>. See also:* [https://www.masterbrewerspodcast.com/062 Interview with Nick Mader on the MBAA podcast.]* [[Brettanomyces_secondary_fermentation_experiment|''Brettanomyces'' secondary pitch rate experiment by Lance Shaner and Richard Preiss.]]* [[Mixed_Fermentation#Staggered_Versus_Co-Pitching|Mixed Fermentation Staggered vs Co-pitching]].* [[Lactobacillus#Effects_on_Mixed_Fermentation|Effects of ''Lactobacillus'' on co-fermentation]]. ==Effects of ''Saccharomyces'' Strain Selection and Staggered vs Co-Pitch==Anecdotally, brewers often claim that the primary strain of ''S. cerevisiae'' makes a difference when co-fermented with ''Brettanomyces''. However, until recently, there has been limited scientific analysis to back this claim, and some brewers might disagree with this claim. Similar differences in anecdotal experiences have been shared by brewers in regards to co-pitching ''Saccharomyces'' and ''Brettanomyces'' at the same time, or adding the ''Brettanomyces'' pitch after the ''Saccharomyces'' fermentation has finished (often called a "staggered pitch"). ===Review of Scientific Analysis===[[File:Tyrawa Fig 15.JPG|thumbnail|250px|right|Figure 15 from [https://atrium.lib.uoguelph.ca/xmlui/handle/10214/14757 Caroline Tyrawa's Masters thesis]. Uploaded with permission from Caroline Tyrawa and Dr. G. van der Merwe's laboratory at University of Guelph Department of Molecular and Cellular Biology.]][[File:Tyrawa Fig 19.JPG|thumbnail|250px|right|Figure 19 from [https://atrium.lib.uoguelph.ca/xmlui/handle/10214/14757 Caroline Tyrawa's Masters thesis]. Uploaded with permission from Caroline Tyrawa and Dr. G. van der Merwe's laboratory at University of Guelph Department of Molecular and Cellular Biology.]]  According to [https://atrium.lib.uoguelph.ca/xmlui/handle/10214/14757 Caroline Tyrawa's masters thesis], some of the flavor impacts of the ''Saccharomyces cerevisiae'' fermentation can remain intact despite the flavor impacts of a subsequent ''Brettanomyces bruxellensis'' fermentation. This indicates that the strain selection for ''S. cerevisiae'' in a co-fermentation with ''B. bruxellensis'' can make a difference to the final product. Tyrawa tested the fermentation of three different strains of ''S. cerevisiae'' and three different strains of ''B. bruxellensis''. The strains of ''S. cerevisiae'' were the Cal Ale strain (neutral), the Vermont Ale strain (fruity), and the St. Remy Belgian strain (phenolic). The three ''B. bruxellensis'' strains were the BSI Drei strain, a strain isolated from a winery, and a strain isolated from a brewery. The ''B. bruxellensis'' strains were selected for their desirable flavor impact in beer as well as their ability to ferment the sugars present in wort. Each of the 6 strains were given a primary-only fermentation. In addition, for each of the ''S. cerevisiae'' strains, they were also co-fermented in combination with each of the ''B. bruxellensis'' strains pitched at one time (a total of 9 combinations). Another set of co-fermentations were done by allowing the ''S. cerevisiae'' strains to ferment for 7 days before adding the ''B. bruxellensis'' strains (staggered pitches). The fermentations were analyzed during a total of 21 days at 22°C. The rate of sugar fermentation was measured, as well as analysis of key flavor compounds <ref name="Tyrawa_Masters">[https://atrium.lib.uoguelph.ca/xmlui/handle/10214/14757 Demystifying Brettanomyces bruxellensis: Fermentation kinetics, flavour compound production, and nutrient requirements during wort fermentation. University of Guelph, Masters Thesis. Department of Molecular and Cellular Biology. 2020.]</ref>. The primary fermentations consumed the wort sugars as would be predicted, with the ''S. cerevisiae'' strains completing fermentation in 5 days, and the ''Brettanomyces'' strains reaching a similar level of attenuation after a 1-2 day lag phase but at a slower rate which continued during all 21 days and probably continuing past 21 days if they were allowed to continue fermentation. For the staggered pitches, the ''S. cerevisiae'' strains appeared to be finished with their fermentation by the time the ''B. bruxellensis'' strains were pitched on day 7. After a day or two of lag, the ''B. bruxellensis'' strains slowly continued to attenuate the wort over the next 14 days and did not taper off at the end of the additional 14 days (21 days total counting the initial ''S. cerevisiae'' fermentation), indicating that attenuation by the ''B. bruxellensis'' strains may not have been finished. For the staggered co-pitches, the highest fermentation rate was achieved with the all three of the B. bruxellensis strains that were co-fermented with the St. Remy Belgian strain and the lowest fermentation rate was with the Cal Ale strain, indicating that the strain choice of ''S. cerevisiae'' affects the fermentation rate over time in combination with the strain of ''B. bruxellensis''. The specific combination of ''B. bruxellensis'' strain and ''S. cerevisiae'' strain can have different effects on fermentation rate as well. For the Cal Ale and Vermont Ale strains, the wine strain of ''B. bruxellensis'' fermented the most efficiently, while the BSI Drei strain fermented most efficiently in combination with the St. Remy Belgian strain. The author did not speculate on why this might be the case. Interestingly, the set of fermentations where both the ''S. cerevisiae'' and ''B. bruxellensis'' were inoculated at the same time did not have this effect. These co-fermentations where the strains were pitched at the same time there looked much like the primary fermentation of the ''S. cerevisiae'' strains where the fermentations were mostly done after 5-6 days with no noticeable attenuation after this short time. This data indicates that higher and slower attenuation occurs when ''Brettanomyces'' is inoculated after the primary ''S. cerevisiae'' fermentation has finished, but not when ''S. cerevisiae'' and ''B. bruxellensis'' are inoculated at the same time <ref name="Tyrawa_Masters" />. Key flavor compounds were analyzed for the different fermentations. Overall, the results showed that some flavor compounds produced by ''S. cerevisiae'' remained even when co-fermented with ''Brettanomyces'' (either co-pitched, or staggered pitch), indicating that the strain selection for ''S. cerevisiae'' for a co-fermentation remains important for the final flavor profile of the beer (see Figure 15). It is also possible that since this experiment was only conducted for 21 days that the ''Brettanomyces'' did not have enough time to have its full flavor impact. In general, there were no significant flavor differences between the co-pitched fermentations versus the staggered pitch fermentations (despite there being a very significant attenuation difference as previously mentioned) <ref name="Tyrawa_Masters" />. The ester profiles of the co-fermentations (both the staggered and co-pitch) were a little bit subdued compared to the primary fermentations with ''Brettanomyces'', indicating that primary fermentations with ''Brettanomyces'' produces higher amounts of esters versus co-fermentation of ''Brettanomyces'' with ''S. cerevisiae''. For example, lower levels of ethyl caproate, ethyl butyrate, ethyl caprylate, ethyl decanoate, ethyl nonanoate, and ethyl lactate, were seen in the co-fermentations versus the ''Brettanomyces'' primary fermentations with some of these compounds dropping below flavor threshold levels (ethyl caproate, for example). The ester production of ''Brettanomyces'' peaked at 14 days, and then esters slowly degraded. In the co-fermentations, the ''Brettanomyces'' appeared to be degrading acetate esters produced by the ''S. cerevisiae'', such as phenyl ethyl acetate, and producing higher amounts of of ethyl acetate. Phenol production began as soon as ''Brettanomyces'' was pitched, and this has been hypothesized to play a large role in replenishing NAD⁺ to alleviate the initial lag growth phase in ''Brettanomyces''. Interestingly, levels of 4-ethylphenol were produced at a faster rate in the 100% ''Brettanomyces'' fermentations, but by the end of the 21 day trial period the the 100% ''Brettanomyces'' ferments had slightly lower concentrations of 4-EP versus the co-fermentations with ''S. cerevisiae'', indicating that perhaps 100% ''Brettanomyces'' fermentations produce more phenols up front, but after some time of aging co-fermentations can produce slightly higher levels of phenols (see Figure 19) <ref name="Tyrawa_Masters" />.

The esters that were analyzed were ethyl acetate, ethyl butyrate, ethyl hexanoate, ethyl decanoate, ethyl octanoate, isoamyl acetate, isobutyl alcohol, and isoamyl alcohol. Ethyl acetate 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). The different co-fermentation rates formed a pattern of more ethyl acetate as the pitching rate of BSI-Drei was increased, but they were still lower than the 100% BSI-565 fermentation. The 75See also:* [https:/25 ratio produced 27 ppm, 50/50 produced 34 ppm, and the 25/75 produced 42 ppm (BSI-565 to BSI-Drei ratio in percent pitching rate)www. Ethyl butyrate was highest in the 100% BSI-565, and curved downward as the pitching rate for the BSI-565 strain was decreasedyoutube. Ethyl butyrate was below odor threshold in the 100% BSI-Drei fermentation. This indicates that the production of ethyl butyrate was dependent on the pitching rate of BSI-565, and that the BSI-Drei strain did not produce significant amounts of this ester. For each of the esters ethyl hexanoate, ethyl decanoate, ethyl octanoate, they had a slight decrease as the pitching rate of BSI-565 decreased, indicating that these esters are produced more by the BSI-565 strain, however the small measured differences may not be reflected in the actual tastecom/aroma of the beers since the differences were so small. The exception was ethyl decanoate which was around 3x higher in the 100% BSI-Drei, which indicates that ethyl decanoate is a major flavor contributor to 100% BSI-Drei fermentationswatch?v=IudVmYyWXss Presentation from Caroline Tyrawa via Escarpment Laboratories Crowdcast video. Overall, the ester concentrations were significantly lower in the BSI-565/BSI-Drei fermentations compared to the strains of ''S. cerevisiae'' and ''B. bruxellensis'' used by [[Brettanomyces_secondary_fermentation_experiment|Lance Shaner and Richard Preiss in their similar experiment]], indicating that total ester concentrations are highly dependent on the strains used. Isoamyl acetate, which was above odor threshold in the 100% BSI-565 fermentation, was almost not detectable in any of the fermentations that contained BSI-Drei (it was 0 ppm in the 100% BSI-Drei fermentation), which is in agreement with other studies that ''Brettanomyces'' hydrolyzes this ester. The alcohols isobutyl alcohol and isoamyl alcohol were slightly decreased as the pitching rate of BSI-565 decreased, and were extremely low in the 100% BSI-Drei, indicating that these alcohols were produced more so by BSI-565.

The phenols that were measured in Mader===''Brettanomyces'' Strain Selection===[https://ir.library.oregonstate.edu/downloads/gh93h631p Riley Humbert's experiment were 4-vinylguaiacol (clove), 4-ethylguaiacol (smokey, spicy), and 4-ethylphenol (medicinal, barnyard). While Bachelors thesis] reported that the 100% BSI-565 ability to hyper attenuate beer in secondary fermentation had high levels of 4-VG ''B. bruxellensis'' is strain dependent with some strains fermenting at a slower rate than others (1800 ppm), they were less than half the amount in this was also the co-fermented ferments (600-800 ppmcase for these strains when primary fermenting wort) but still above odor threshold (300 ppm) (the different ratios of BSI-565 to BSI-Drei . The fermentation rate did not have a large impact)correlate to phenol production; for example, and 4-VG was below threshold in one strain that produced the 100% BSI-Drei fermentation. most 4-EG vinyl phenol and 4-EP had high levels in the co-fermentations with BSI-565 and BSI-Drei and the 100% BSI-Drei, and ethyl phenol was one of the ratios did not have a large impactslowest fermenters. This is in agreement with another experiment by [[Brettanomyces_secondary_fermentation_experiment|Lance Shaner and Richard Preiss]] Humbert also reported that showed that pitching rate strains of ''BrettanomycesB. bruxellensis'' after fermentation isolated from beer performed better than those isolated from wine, which is in agreement with ''S. cerevisiae'' did not have a great affect on the levels of phenols produced previous experiments <ref>[https://wwwir.facebooklibrary.comoregonstate.edu/groupsdownloads/MilkTheFunk/1935201276508077/ Nick Madergh93h631p Riley Humbert for the degree of Honors Baccalaureate of Science in Chemical Engineering presented on May 21, 2021. 2017 Master Brewers Conference Presentation. 2017Title: Performance of Brettanomyces Yeast Strains in Primary and Secondary Beer Fermentations.]</ref>.