General considerations for yeast and GF brewing
Dry yeast usually sold in 11.5g sachets is generally gluten free and safe for brewing. Most companies label this product as gluten free as well. Liquid yeast is typically not safe for GF brewing due to being propagated on non-GF media. There are examples of GF liquid yeast but they're in the small minority at this time.
Liquid yeast and cross contamination risk
With very few exceptions (noted below), yeast in liquid form is propagated and sold in barley-based media. For this reason, commercial liquid brewer's yeast would not be considered gluten free or safe for individuals with a medical reason to avoid gluten (celiac disease or otherwise). Although the volume of gluten in a liquid yeast sample diluted within a batch of beer is arguably small, that amount can still pose a real risk and would fail to meet the standards of dedicated gluten free breweries and the Zero Tolerance Home Brew Club.
Yeast Basics and Nutrition
Yeast are living (albeit pretty simple) organisms, that need the proper environment and nutrition to thrive and do the work we ask of them. Understanding how yeast work and what they need to perform well can help brewers get the results they want and limit surprises (slow or stuck fermentations, off flavors, etc).
- Escarpment Labs yeast basics webinar series: Part One - Intro, Part Two - Flavor production, Part Three - Harnessing Yeast Flavour, Part Four - Q&A
- Escarpment Labs Diastaticus 101 webinar -- Understanding the mechanism behind super attenuative saison strains
Impact on sorghum twang
Some gluten free brewers and beer drinkers associate a "twang" with some sorghum-based beers. One generally accepted explanation is that sorghum on its own is deficient in some nutrients required by the yeast, particularly free amino nitrogen (FAN). Adding a yeast nutrient high in FAN, it is reported, can help to overcome this perceived off flavor.
Gluten Free Yeasts and Bacterias Available
List of Manufacturers with Gluten Free Offerings
- Propagate Lab is based in Golden, Colorado. Although they normally produce liquid yeast propagated on barley wort for conventional commercial brewers, since 2019 they have been working with GlutenFreeHomeBrewing.com to provide homebrew-scale liquid pitches propagated on gluten free media. A selection of yeast strains are ordered in advance by GFHB with customer input and those yeasts are shipped from GFHB's Oregon location on a seasonal (cool-weather) basis.
- For commercial sized pitches, Imperial offers all of their saccharomyces strains on gluten free media as special orders, with a 20L minimum and ~4 week lead time. In the past they have offered a limited number of strains as homebrew sized pitches on GF media. Imperial may have other seasonal offerings in the future.
- Mangrove Jack's
Saccharomyces cerevisiae (Brewer's Yeast)
List of commercial gluten free saccharomyces cerevisiae strains
Note that descriptions in quotes in the Notes column come from the yeast manufacturers websites. References to "wheat beers" styles are unedited since it is possible to create similar flavor profiles using gluten free grains (i.e. without wheat).
|WB-06||Fermentis||Dry||Medium||Y||Y||86-90||Low||64-75||"Wheat beer" styles (hefeweizen, dunkelweiss), Belgian wit||POF+ more likely to produce clove phenolics. "Produces well-attenuated beers and it is ideal for wheat base beers, such as Belgian and German Styles (Ex. Wit Beers and Weizen Beers). Produces typical phenolic notes of wheat beers. Allows to brew beer with a high drinkability profile and presents a very good ability to suspend during fermentation."|
|BE-256||Fermentis||Dry||Med-High||N||N||82 - 86||High||59-68||Belgian ales, e.g. Abbey and Dubbel||"Active dry brewer’s yeast recommended to ferment a diversity of Belgian type beers such as abbey style known for its fruitiness and high alcohol content. It ferments very fast and reveals strong fermentation aromas. To maintain the aromatic profile at the end of the fermentation, we do recommend to crop this yeast as soon as possible after fermentation"|
|T-58||Fermentis||Dry||Med-High||Y||N||80 - 82||POF+ more likely to produce clove phenolics. "Specialty brewer’s yeast selected for its strong fermentation character, intense fruity and phenolic flavors – especially banana, clove and peppery notes. Suitable for a great variety of wheat-base beers and fruity-spicy oriented styles. Yeast with a medium sedimentation: forms no clumps but a powdery haze when resuspended in the beer."|
|S-33||Fermentis||Dry||Medium||N||N||68-72||Belgian ales, imperial stout||"Fruity driven strain, gives a high mouthfeel and body to the beer. Ideal for Belgian Ales (Blond, Dubbel, Tripel, Quadrupel Styles) and strong English ales (ex. Imperial Stouts). It is also ideal for New England IPA’s. Yeast with a medium sedimentation: forms no clumps but a powdery haze when resuspended in the beer."|
|K-97||Fermentis||Dry||Med-Low||N||N||80-84||64-78 (18-26°C)||German ale, Irish stout||"German ale brewer’s yeast producing subtle fermentation character. Depending on the conditions tend to present floral and balanced fruity character. Ideal for delicate beers such as German Kolsch beers, Belgian Wits and some versions of Session Beers. Suitable for heavily hopped beers and has ability to form a large firm head when fermenting."|
|S-04||Fermentis||Dry||Low||N||N||74-82||"English ale brewer’s yeast selected for its fast fermentation profile. Produces balanced fruity and floral notes. Due to its flocculation power, tends to produce beers with higher clarity. Ideal for a large range of American and English Ales – including highly hopped beers – and is specially adapted to cask-conditioned and beers fermented in cylindro-conical tanks."|
|US-05||Fermentis||Dry||Low||N||N||78-82||Medium||"American ale brewer’s yeast producing neutral and well-balanced ales, clean and crispy. Forms a firm foam head and presents a very good ability to stay in suspension during fermentation. Ideal for American beer types and highly hopped beers."|
|S-189||Fermentis||Dry||Low||N||N||80-84||53-59||Neutral flavours. Floral and hoppy lagers||"Originating from the Hürlimann brewery in Switzerland. This lager yeast strain’s profile allows to brew fairly neutral flavor beers with a high drinkability. Depending on the conditions, it tends to present noticeable herbal and floral notes to lager beers."|
|W-34/70||Fermentis||Dry||Low||N||N||80-84||"This famous brewer’s yeast strain from Weihenstephan in Germany is used world-wide within the brewing industry. SafLager™ W-34/70 allows the brewing of beers with a good balance of floral and fruity aromas and gives clean flavors and high drinkable beers."|
|S-23||Fermentis||Dry||Low||N||N||80-84||"Bottom fermenting brewer’s yeast originating from Berlin in Germany. It’s recommended for the production of fruitier and more estery lagers. Its profile gives beers with a good length on the palate."|
|BE-134||Fermentis||Dry||Medium||Y||Y||89-93||64-82||Saison||POF+ more likely to produce clove phenolics "This typical brewer’s yeast strain is recommended for well-attenuated beers, produces fruity, floral and phenolic notes and a dry character. Produces highly refreshing beers, it is ideal for Belgian-Saison style."|
|Abbaye Belgian||Lallemand||Dry||Medium||N||High||Med-High||63 - 77||Belgian White, Belgian Blonde, Belgian Golden, Dubbel, Tripel, and Quad||"LalBrew Abbaye is an ale yeast of Belgian origin. Selected for its ability to ferment Belgian style beers ranging from low to high alcohol, Abbaye produces the spiciness and fruitiness typical of Belgian and Trappist style ales. When fermented at higher temperatures, typical flavors and aromas include tropical, spicy and banana. At lower temperatures Abbaye produces darker fruit aromas and flavors of raisin, date and fig. "|
|Belle Saison||Lallemand||Dry||Low||Y||High||Low||59 - 95||Saison||"LalBrew Belle Saison is a Belgian-style ale yeast selected specifically for its ability to create Saison-style beers. Belle Saison is a diastaticus strain that allows the brewers to achieve the high attenuation characteristic of this classic style. Designed for warm-temperature fermentation true to traditional “Farmhouse” production methods, beers brewed with Belle Saison are fruity, spicy and refreshing."|
|BRY-97 West Coast||Lallemand||Dry||Low||N||N||Med-High||High||59 - 72||Cream Ale, American Wheat, Scotch Ale, American Pale Ale, American Amber, American Brown, American IPA, American Stout, Russian Imperial Stout, Imperial IPA, Roggen/Rye, Old Ale and American Barleywine||"An American West Coast-style ale yeast that was selected from the Siebel Institute Culture Collection for its ability to produce high quality ales. BRY-97 is a neutral strain with a high flocculation ability that can be used to make a wide variety of American-style beers. Through expression of a --glucosidase enzyme, BRY-97 can promote hop biotransformation and accentuate hop flavor and aroma."|
|Diamond Lager||Lallemand||Dry||Low||N||N||High||High||50 - 59||Munich Helles, Dortmunder Export, German Pilsner, Bohemian Pilsner, American Pilsner, Vienna Lager, Oktoberfest/ Märzen, Dark American Lager, Munich Dunkel, Schwarzbier, Traditional Bock, Doppelbock, Eisbock and California Common||"LalBrew Diamond Lager yeast is a true lager strain originating in Germany Diamond Lager yeast delivers excellent fermentation performance, and has the ability to produce clean, authentic lagers. "|
|CBC-1||Lallemand||Dry||N||N?||68||Fruit beers, full-bodied, malty ales dry cider and mead||"LalBrew CBC-1 has been specifically selected from the Lallemand Yeast Culture Collection for its refermentation properties and is recommended for Cask and Bottle Conditioning. CBC-1 referments beer efficiently due to its high resistance to alcohol and pressure. The flavor is neutral, therefore the original character of the beer is preserved. The yeast will settle and form a tight mat at the end of refermentation. CBC-1 can be used for primary fermentation of dry ciders or mead. Maltotriose is not metabolized during primary fermentation of beer, so CBC-1 is well suited for sweeter fruit beers or full-bodied, malty ales."|
|Belgian Wit||Lallemand||Dry||Med||?||N||Med-High||Low||63 - 72||Belgian Witbier, American Wheat, Berliner Weiss, Gose, Hefeweizen, Dunkelweis, and Weizenbock||"LalBrew Wit yeast is a relatively neutral strain which can be used to produce a wide variety of wheat beer styles. Ester and phenol production is lower than for traditional hefeweizen strains such as Munich Classic. LalBrew® Wit provides a baseline profile of banana and spice aromas, but leaves space for the brewer to showcase other spice additions typical of Belgian style beers."|
|London||Lallemand||Dry||Med||N||N||Medium||Low||65 - 72||Extra Special Bitter, Pale Ale, Bitter and Mild||"LalBrew London is a true English ale strain selected for reliable fermentation performance and moderate ester production that lets the flavors and aromas of malt and hops shine through."|
|Munich Wheat||Lallemand||Dry||Med-High||Likely||N||Med-High||Low||63 - 72||Weizen/Weissbier, Dunkelweizen and Weizenbock||LalBrew® Munich Classic is a Bavarian wheat beer strain selected from the Doemens Culture Collection. It imparts the spicy and fruity aroma profile typical of German wheat beer styles. This strain is simple to use over a wide range of recipe variations and fermentation conditions, making it a great choice for a number of traditional styles of wheat beer. A true top-cropping yeast, Munich Classic can be skimmed off the top of classic open fermentation vessels in the traditional manner.|
|Nottingham||Lallemand||Dry||Low||N||N||High||High||50 - 72||Pale Ales, Ambers, Porters, Stouts, Barleywines, Golden Ale, Kölsch, Lager-style beers, IPA, and Imperial Stout||"LalBrew Nottingham is an English style ale yeast selected for its high performance and versatility for a wide variety of styles and fermentation conditions"|
|Windsor||Lallemand||Dry||Med||N||N||Medium||Low||Milds, Bitters, Irish Reds, English Brown ales, Porters, Sweet Stouts||"LalBrew Windsor ale yeast is a true English strain that produces a balanced fruity aroma and imparts a slight fresh yeasty flavor. Beers created with Windsor are usually described as full-bodied, fruity English ales. Brewers choose Windsor to produce beers that range from Pale Ale to Porter with moderate alcohol levels and the flavor and aroma characteristics of the best traditional ales."|
|New England||Lallemand||Dry||Med-High||N||N||Med-High||Medium||59 - 72||NEIPA||"LalBrew New England is an ale strain selected specifically for its ability to produce a unique fruit-forward ester profile desired in East Coast styles of beer. A typical fermentation with LalBrew New England will produce tropical and fruity esters, notably stone fruits like peach. Through expression of a -glucosidase enzyme, New England can promote hop biotransformation and accentuate hop flavor and aroma. LalBrew New England exhibits medium to high attenuation with medium flocculation, making it a perfect choice for East Coast style ales."|
|Kolsch||Lallemand||Dry||Med-Low||N||N||Med-High||Med-High||54 - 68||Kölsch||"LalBrew Köln is ideal for brewing traditional Kölsch-style beers and other neutral ales. The neutral character of this strain accentuates delicate hop aromas while imparting subtle fruity esters. Through expression of a β-glucosidase enzyme, Köln can promote hop biotransformation and accentuate hop flavor and aroma. Colder fermentations will be more neutral in character, while warmer fermentations will have a more fruit-forward ester profile."|
|Voss Kveik||Lallemand||Dry||Med||N||N||Med-High||Very High||77 - 104||Norwegian farmhouse ales, fastfermented neutral ales (and quick sours)||"Kveik is a Norwegian word meaning yeast. In the Norwegian farmhouse tradition, kveik was preserved by drying and passed from generation to generation. Kveik is the original, traditional dried yeast! The LalBrew Voss strain was obtained from Sigmund Gjernes (Voss, Norway), who has maintained this culture using traditional methods since the 1980’s and generously shared it with the wider brewing community. LalBrew Voss supports a wide range of fermentation temperatures between 25-40°C (77-104°F) with a very high optimal range of 35-40°C (95-104°F). Very fast fermentations are achieved within the optimal temperature range with full attenuation typically achieved within 2-3 days. The flavor profile is consistent across the entire temperature range: neutral with subtle fruity notes of orange and citrus. Flocculation is very high producing clear beers without filtration or use of process aids."|
|Sourvisiae||Lallemand||Dry||N||N||Med-High||Med-High||50 - 72||Sour beers||"Sourvisiae is a bioengineered ale yeast strain (Saccharomyces cerevisiae) capable of producing lactic acid during fermentation to provide brewers with an easy, reproducible, and mono-culture product for sour-style beer production. Sourvisiae contains a single genetic modification, a lactate dehydrogenase gene from a food microorganism, which enables the yeast to produce high levels of lactic acid, the main compound that gives sour beers their flavor. Sourvisiae does not produce other flavor compounds associated with Brettanomyces, Lachancea, or Lactic Acid Bacteria, providing a cleaner and more reproducible souring process, with much shorter fermentation times. "|
|Verdant IPA||Lallemand||Dry||Med-High||N||N||Med-High||Medium||64 - 73°F||NEIPA, English IPA, American Pale, English Bitter, Sweet Stout, Sours||"LalBrew® Verdant IPA was specially selected in collaboration with Verdant Brewing Co. (UK) for its ability to produce a variety of hop-forward and malty beers. Prominent notes of apricot and undertones of tropical fruit and citrus merge seamlessly with hop aromas. With medium-high attenuation, LalBrew® Verdant IPA leaves a soft and balanced malt profile with slightly more body than a typical American IPA yeast strain. This highly versatile strain is well suited for a variety of beer styles including NEIPA, English IPA, American Pale, English Bitter, Sweet Stout and Sours."|
|M15 Empire Ale||Mangrove Jack's||Dry||Med?||N?||N||70-75||High||64-72°F||"A top-fermenting ale yeast suitable for a variety of full bodied ales, with exceptional depth. Ferments with full, rich dark fruit flavours."|
|M20 Bavarian Wheat||Mangrove Jack's||Dry||High?||Likely||No||70-75||Low||64-86°F||"A top-fermenting wheat beer yeast which imparts banana and clove esters balanced with spiced aromas. This yeast produces a silky mouthfeel and rich body."|
|M21 Belgian Wit||Mangrove Jack's||Dry||Med?||Likely||No||70-75||Low||64-77°F||"A traditional, top-fermenting yeast that has a good balance between fruity esters, and warming spice phenolics. The yeast will leave some sweetness, and will drop bright if left long enough."|
|M29 French Saison||Mangrove Jack's||Dry||Med?||Likely||85-90||Medium||79-90°F||"French Saison yeast is an exceptional, highly attenuative top-fermenting ale yeast, creating distinctive beers with spicy, fruity and peppery notes. Ideal for fermentation of farmhouse style beer."|
|M31 Belgian Tripel||Mangrove Jack's||Dry||High||?||?||82-88||Medium||64-82°F||"Provides a fantastic complex marriage of spice, fruity esters, phenolics and alcohol. It is also very attenuative with a high alcohol tolerance making it perfect for a range of Belgian styles."|
|M36 Liberty Bell Ale||Mangrove Jack's||Dry||Med?||N||N||74-78||High||64-73°F||"A top-fermenting ale yeast suitable for a wide variety of hoppy and distinctive style beers. This strain produces light, delicate fruity esters and helps develop malt character."|
|M41 Belgian Ale||Mangrove Jack's||Dry||High||Likely||?||82-88||Medium||64-82°F||"Spicy and phenolic, this yeast emulates the intensity and complexity of some of the best monastic breweries in Belgium, high attenuation and alcohol tolerance allows you to brew a huge range of Belgian beers."|
|M42 New World Strong Ale||Mangrove Jack's||Dry||Low||N||N||77-82||High||61-73°F||"A top-fermenting ale strain suitable for many types of ales of all strengths. Ferments with a neutral yeast aroma to ensure the full character of the malts and hops are prominent in each beer."|
|M44 US West Coast||Mangrove Jack's||Dry||Low||N||N||77-85||High||64-73°F||"A top-fermenting ale strain suitable for American style ales. This yeast produces an exceptionally clean flavour, ideal for when you want the hop character to really punch through."|
|M47 Belgian Abbey||Mangrove Jack's||Dry||High||?||N?||73-77||High||64-77°F||"Moderately alcohol tolerant with fewer phenols than Belgian Ale, this yeast is exceptionally fruity with hugely complex esters and is highly flocculant."|
|M54 Californian Lager||Mangrove Jack's||Dry||Low||N||N||77-82||High||64-68°F||"A unique lager yeast that has the ability to ferment at ale temperatures without the associated off flavours. Extended lagering periods are also not required."|
|M76 Bavarian Lager||Mangrove Jack's||Dry||Low||N||N||75-80||Medium||46-57°F||"A bottom-fermenting yeast suitable for most lager styles. Promotes less sulphur production than other lager strains, as well as a fuller, more rounded malt character with well-promoted hop flavours."|
|M84 Bohemian Lager||Mangrove Jack's||Dry||Low||N||N||72-76||High||50-59°F||"A bottom-fermenting lager yeast characterised by its dry and clean palate typical of traditional Czech brewing. Produces soft, delicate and well balanced beers."|
|M12 Kveik||Mangrove Jack's||Dry||Med||N||N||77-82||High||86-104°F||"A top fermenting yeast, Voss Kveik offers fast fermentation at very high temperatures whilst retaining a neutral flavour character with subtle citrus fruit notes."|
|Various||Propagate Lab||Liquid||To be updated when GFHB releases 2020 strain availability.|
Strain equivalents - Saccharomyces cerevisiae
The following commercial strains may be equivalent or derive from a similar brewery source. Commercial labs that do not offer gluten free strains, i.e. Wyeast and White Labs (WLP), are included for comparison only.
|W-34/70 Saflager||2124 Bohemian Lager||830 German Lager||Weihenstephan 34/70|
|MP-100 Chico Ale Variant 1||US-05 Safale||1056 American Ale||001 California Ale Yeast||May not be identical to 1056/WLP001, but close relative. "Chico", Sierra Nevada|
|S-04 Safale||n/a||006 Bedford British Ale||Bedford? S-04 may be WLP006 OR Wyeast 1028/WLP013|
|S-04 Safale||1028 London Ale||013 London Ale||Worthington White Shield. S-04 may be WLP006 OR Wyeast 1028/WLP013|
|WB-06 Safale||3068 Weihenstephan Weizen||300 Hefeweizen Ale||Weihenstephan 68|
|MP-302 French Saison||Belle Saison ??||BE-134 Safale||3711 French Saison||590 French Saison?||Saison du Pont|
|n/a||K-97 Safale||1007 German Ale||n/a||Descendent of WLP003 German Ale II, Duseeldorf (Zum Uerige?). Not WLP036|
|MIP-211 Belgian Ale I||1214||500||Chimay|
|MIP-??? Czech Style Lager|
|MIP-431 English Ale I||1958||002||Fuller's|
Brettanomyces is a yeast genus closely related to but distinct from the saccharomyces family. Although some alcohol producers (particularly vintners) see it as a source of "spoilage", many within the craft brewing tradition embrace "Brett" and its unique flavor contributions which can range from tropical fruit to "barnyard". For more information see:
- Sour and Mixed Culture Beers
- Milk the Funk Facebook group
- Milk the Funk Wiki: Brettanomyces
- American Sour Beers (Brewers Publications)
Funky not sour -- Take note that beers made with Brettanomyces but with no lactic or acetic acid bacteria may be "funky" (e.g. barnyard, phenolic, etc) but not sour. It is common for mixed culture beers to include both Brettanomyces and lactic acid producing bacteria, but they are not one and the same.
List of commercial Brettanomyces strains -- Some seasonal availability on gluten free media
The following strains are available in the Propagate Lab yeast library. Since 2019 GlutenFreeHomeBrewing.com is working with Propagate Lab to pre-order specific liquid yeast strains that will be carried by GFHB and available for order during cooler months. In 2019 there were no Brett strains available, however there has been interest among some customers to include Brett strains going forward.
|MIP-701||Propagate Lab||Brett Brux I||A classic strain used for secondary fermentation in Belgian-style beers such as lambics, MIP-701 creates a medium-intensity, earth-forward character in finished beer. A historic brewery in Belgium uses this yeast in secondary fermentation and bottling to produce the signature flavor of its beer.||Orval?|
|MIP-702||Propagate Lab||Brett Brux II||A classic strain used for secondary fermentation in Belgian-style beers such as lambics. It creates a medium-intensity, earth-forward character in finished beer. Balanced between barnyard and fruit.|
|MIP-703||Propagate Lab||Brett Brux III||A classic strain used for secondary fermentation in Belgian-style beers such as lambics. This particular brett is very fruity with tropical fruit dominating the aroma.|
|MIP-710||Propagate Lab||Brett Stave I||A classic strain used for secondary fermentation in Belgian-style beers such as lambics. This particular strain was isolated from a Colorado Brewery and produces intense fruit notes.||Crooked Stave|
|MIP-714||Propagate Lab||Brett Stave IV||This strain was isolated from a bottle of beer originally produced in the Netherlands. It produces barnyard like aromas and is a very aggressive brett strain.||Crooked Stave|
|MIP-720||Propagate Lab||Brett clausenii||A classic strain used for secondary fermentation in Belgian-style ales and English Old Ales. The yeast can be fairly neutral in aroma and works well by itself. When it is paired with a phenol producing yeast it will create barnyard like aromas.|
|MIP-750||Propagate Lab||Brett tool||Isolated from a bottle of European beer fermented with fruit, this is an aggressive Brett strain that produces strong barnyard aroma. Works well as a blend.|
|MIP-760||Propagate Lab||Brett phantom||Isolated from a famous saison producer, this is a highly fruity brett that will ferment well by itself or pitched into a blend. This unique brett has helped several brewers medal at GABF.|
|MIP-765||Propagate Lab||Native Brett Blend||This is a unique blend of bretts isolated from a number of natural sources. Isolates are from plums, natural wines, wild plants, and spontaneous fermentation. This blend will add complexity to any beer.|
|MIP-770||Propagate Lab||Brett imposter||This is not Brett! What is it? A Saccharomyces that is fruity, not very floculant, and a good attenuator. It works well in an IPA, or an "all brett beer" that you do not want to actually use brett in.|
Lactic Acid Bacteria and Acid Producing Yeast
There are a number of readily available sources of lactic acid producing bacteria, some specifically marketed to the brewing community, and others available in grocery stores and your own kitchen. Lactic acid bacteria (LAB) are used in making intentionally sour and mixed culture beers. LAB generally includes Lactobacillus (commonly referred to as "lacto" -- not to be confused with lactose sugar), Pediococcus, and some non-conventional yeasts like Pichia and Lachancea.
- Commercial souring cultures for the brewing community
- Other sources for LAB
- Live culture yoghurt and kefir
- Live culture kombucha
- Probiotic products (e.g. GoodBelly)
- Sourdough bread making cultures
For more information on lactic acid bacteria sources, see also Milk the Funk Wiki: Lactobacillus and Pediococcus pages. Note that some of the commercially available bacterias indicated on Milk the Funk will not be available on gluten free medium.
Cultivating GF yeast and bacteria from liquid samples
Although most of the liquid yeast products currently available commercially are not safe for direct use in gluten-free brewing (Propagate Labs cultures sold by Gluten Free Homebrewing being an exception), there are methods that would allow GF brewers to cultivate the desired material in a gluten-free medium. Although there is significant reference material for both of the methods below, there is little to no focus on doing this for the purpose of making yeast and bacteria safe for GF brewing. At this point there are no studies on the effectiveness of either method -- or number of iterations required -- to effectively reduce the risk of cross contamination to levels safe for those with a medical reason to avoid gluten.
Agar plates and slants
This involves taking a very small sample of liquid yeast or bacteria using an inoculation loop, and streaking those cells out onto an agar plate made from gluten free media. The (desired) yeast or bacteria cells are allowed to grow for several days before repeating that process onto a new plate (to isolate a specific microorganism where there may be multiple in the sample), onto an agar slant (for longer term storage in a freezer), or gradually propagating the sample in GF wort until there is a sufficient cell count to introduce into the target beer.
Equipment and material needed
- Petri dishes
- Inoculation loop
- Bunsen burner or alcohol lamp
- Used to create a protected work area around the perimeter of the flame in which to do culturing work, mitigating the risk of other microbes entering the picture
- Agar powder
- Yeast nutrient
- Growth media (GF wort, dextrose, etc)
- Slants (optional)
- Crystal violet (optional, for selectively growing Brettanomyces)
- CV should inhibit all domesticated yeast, lactic acid bacteria and pediococcus, allowing some wild yeasts and Brettanomyces to grow
General outline of steps
- Sui Generis Brewing videos and blog