Yeast & Fermentation Research Directory
This directory family maps two of the three inputs to a gluten-free fermentation — the grains and the enzymes. This page is the third.
It is not a borrowed subject. Gluten-free wort differs from barley wort in ways that land directly on the yeast: free amino nitrogen runs chronically low, and sorghum wort is glucose-forward rather than maltose-forward — a difference the Queensland proteomics work traced to an abundant α-glucosidase rather than to amylases. Sugar uptake order, attenuation behaviour, and stress response all move as a result. The commercial layer here is also unusually open: yeast houses publish strain data, trial results, and technical notes far more freely than the enzyme producers do, which makes this one of the better-documented corners of the field.
How to read it: the same categories as the sorghum directory, with the same rules. Entries are brief, factual, dated, and linked to primary sources. Descriptions are not endorsements.
Coverage is US-centered by design — this site works in the American supply chain — with international anchors included where the science is foundational.
Directory established 2026-08-25 · first verification pass 2026-08-26.
Key topics — find entries by subject, across every category
How to read it: each topic lists the entries that touch it, so a reader hunting one subject can jump straight to the right sections.
The aroma gap — why gluten-free beer tastes thinner, and what does not fix it: the 2021 and 2024 Coastal Carolina studies (Literature), the group behind them (Institutions, Contributors), and the unexplained mechanism (Research gaps).
Nitrogen and the low-FAN wort — the constraint that defines fermentation on these grains: the supplementation trial and the Pretoria nitrogen work (Literature), and the grown-enzyme answer (How the field connects).
What the yeast is handed — why sorghum wort ferments differently: the α-glucosidase proteomics (Literature), and its link back to the internal enzymes wing (How the field connects).
Choosing and sourcing a strain — the six strain houses and the cross-supplier concordance chart (Suppliers & Industry), the non-Saccharomyces options and the strains already isolated from traditional beer (Literature).
1. Institutions — federal labs, universities, and international centers doing brewing-relevant yeast work
— US universities —
Coastal Carolina University — Department of Chemistry — Conway, South Carolina. The group behind the two controlled studies comparing aroma output of sorghum and barley beers, and the only US programme we have found whose published work is specifically the fermentation chemistry of a gluten-free grain. The 2024 study · Verified 2026-08-26
University of Florida — Food Science and Human Nutrition — Gainesville, Florida. Collaborating institution on the 2024 yeast-strain volatiles work. The 2024 study · Verified 2026-08-26
Oregon State University — Fermentation Science, Department of Food Science and Technology — Corvallis, Oregon. One of the few dedicated US fermentation science programmes. Its research brewery runs a full beer quality laboratory measuring alcohol, residual extract, colour, haze, package gases, diacetyl, fermentation esters and foam stability — the exact instrument set this page's subject requires, and one gluten-free brewing has no equivalent of. Fermentation Science · facilities · Verified 2026-08-26
University of California, Davis — Food Science and Technology — Davis, California. The US brewing-science school, running brewing science and technology instruction on yeast fermentation. Brewing Science and Technology · Verified 2026-08-26
Penn State University — Department of Food Science — University Park, Pennsylvania. The funded US gluten-free brewing programme, and the one working directly on this page's constraint: its grant evaluates unmalted gluten-free grains and enzyme supplementation to establish best practice for producing sufficient fermentable sugars and free amino nitrogen. It also developed the ExGM decoction mashing procedure, on which the university has filed a provisional patent — gluten-free malts reaching high fermentable-sugar concentrations without enzyme dosing. The research · fermentation faculty · Verified 2026-08-26
Cornell University — Cornell Craft Beverage Institute, Cornell AgriTech — Geneva, New York. An automated pilot brewery plus the Cornell Craft Beverage Analytical Lab for testing and sensory appraisal, with a brewing extension programme serving New York producers. Training covers fermentation microbiology and sensory evaluation — the two capabilities the aroma-gap question needs and gluten-free brewing lacks. Beer research and extension · yeast and fermentation course · Verified 2026-08-26
Kansas State University — IGP Institute, Grain Science — Manhattan, Kansas. Runs a brewing and fermentation science course covering brewing science, technology and sensory analysis. Kansas State recurs across this directory more than any other institution on the grain side; this is its fermentation-facing arm. Brewing and fermentation science · Verified 2026-08-26
University of California, Davis — Food Science and Technology. Runs brewing science and technology instruction covering yeast fermentation; appears on six pages of this directory already. Brewing Science and Technology · Verified 2026-08-26
Washington State University. Recurs across four pages of this directory on the grain side; its food science programme is the nearest US institution to this subject not yet publishing in it. Verified 2026-08-26
Colorado State University. Carries the 1998 Muoria diastatic-power comparison this directory cites on the enzyme side, and appears on three directory pages. Verified 2026-08-26
University of Arkansas. The rice-malting programme this directory already maps — the institutional route by which a second gluten-free grain could get controlled fermentation data. Verified 2026-08-26
Purdue University. Recurs across three directory pages; food science and cereal chemistry capacity relevant to wort composition. Verified 2026-08-26
Wayne State College — Fermentation Science — Nebraska. A dedicated undergraduate fermentation science degree, one of the small number in the United States. The programme · Verified 2026-08-26
— International anchors —
University of Pretoria — South Africa. Holds the standing thesis work on yeast fermentation of sorghum worts and the influence of nitrogen sources — the question that defines fermentation on this grain. Repository record · Verified 2026-08-26
University of Queensland — Australia. The proteomics and metabolomics work identifying an abundant α-glucosidase as the driver of sorghum fermentability — the finding this page's own framing rests on, and the reason sorghum wort is glucose-forward rather than maltose-forward. The preprint · Verified 2026-08-26
Four US institutions and two international anchors. The imbalance runs the other way from most pages in this family: fermentation science is well established in US universities, but almost none of it is pointed at gluten-free grain. Coastal Carolina is the exception.
2. Contributors — the researchers behind the work
— US researchers —
Drew Budner — Professor, Department of Chemistry, Coastal Carolina University. Lead author on both the 2021 aroma-profile study and the 2024 yeast-strain study, and presenting sorghum beer work at ASBC as early as 2017. The most sustained US research line on gluten-free fermentation chemistry we have found. 2017 ASBC proceedings · the 2024 study · Verified 2026-08-26
Darrell Cockburn — Assistant Professor of Food Science, Penn State. Principal investigator on Gluten-Free Beer Production in Pennsylvania Using Unmalted Grains, and co-developer of the ExGM decoction mashing procedure. His group's stated aim — sufficient fermentable sugars and free amino nitrogen from gluten-free grain — is this page's central problem, funded and under way in the United States. Faculty page · the research · Verified 2026-08-26
Katherine A. Thompson-Witrick — Food Science and Human Nutrition, University of Florida. Co-author on the 2024 yeast-strain volatiles study; the food-science half of the collaboration. The 2024 study · Verified 2026-08-26
Lin et al. (2022) — protease-assisted amino acid release. The group behind the demonstration that proteases during mashing can selectively release amino acids to improve lager aroma. Named here because it is the only work we have found that treats the aroma problem as a nitrogen problem. The paper · Verified 2026-08-26
Rautio & colleagues — maltose transport in brewer's wort. The standing characterisation of how brewing yeast actually takes up maltose under wort conditions. The paper · Verified 2026-08-26
Joseph Carr — Department of Chemistry, Coastal Carolina University. Co-author, 2024 yeast-strain study. The study · Verified 2026-08-26
Brett Serafini — Department of Chemistry, Coastal Carolina University. Co-author, 2024 yeast-strain study. The study · Verified 2026-08-26
Samantha Tucker — Department of Chemistry, Coastal Carolina University. Co-author, 2024 yeast-strain study. The study · Verified 2026-08-26
Elisabeth Dieckman-Meyer — Department of Chemistry, Coastal Carolina University. Co-author, 2024 yeast-strain study. The study · Verified 2026-08-26
Lindsey Bell — Department of Mathematics and Statistics, Coastal Carolina University. The statistician on the 2024 study. Named here deliberately: the paper's central claim is a negative result — that strain choice did not significantly move the outcome — and a negative result is only as good as the statistics behind it. The study · Verified 2026-08-26
3. Projects & Grants — funded work in flight right now
What qualifies: funding a gluten-free brewer or researcher could actually pursue for fermentation work, plus the research lines currently producing output. Described, never endorsed.
— US funding a fermentation project could be taken to —
USDA NIFA — Agriculture and Food Research Initiative (AFRI). The largest US competitive agricultural grants programme, ~$140M for FY2026. Its Food Safety, Nutrition and Health priority area reaches fermentation performance on gluten-free grain. AFRI · Verified 2026-08-26
Brewers Association — Craft Beer Research and Service Grants. Funds brewing-science research directly. Fermentation performance on alternative grains sits squarely inside its remit. The programme · Verified 2026-08-26
ASBC Foundation — project funding. Grants toward work advancing brewing science, including new analytical methods. ASBC already carries Budner's sorghum fermentation work in its proceedings. ASBC · Verified 2026-08-26
Pennsylvania Malt and Brewed Beverage Industry Promotion Program. State money whose scope is brewing itself — the one US public funder in this directory aimed at the industry rather than a crop. Program page · Verified 2026-08-26
Gluten-Free Beer Production in Pennsylvania Using Unmalted Grains (Penn State). A $53,514 award to Darrell Cockburn, part of roughly $300,000 in beer grants approved across four Penn State researchers. Evaluates unmalted gluten-free grains and enzyme supplementation to develop best practice for producing sufficient fermentable sugars and free amino nitrogen. The only funded US project we have found aimed squarely at the FAN problem. Grant coverage · Verified 2026-08-26
The ExGM decoction mashing procedure (Penn State). A modified mashing method for gluten-free malts reaching high fermentable-sugar concentrations without enzyme supplementation, with a provisional patent filed. Relevant here because what reaches the yeast is decided by how the mash was run. The procedure · Verified 2026-08-26
— Research lines currently producing output —
The Coastal Carolina sorghum fermentation line (2017– ). A sustained programme rather than a single study: ASBC proceedings in 2017, the aroma-profile paper in 2021, the yeast-strain study in 2024. Each round narrows the same question — what actually determines the character of a sorghum beer. 2017 · 2024 · Verified 2026-08-26
Millet-based beer fermentation and volatile formation (2026). Recent work extending the same comparative method from sorghum to millet, against barley as reference. The study · Verified 2026-08-26
4. Funders & Programs — who pays for the work (described, never endorsed)
What qualifies: a funder whose money traceably appears in work documented here, or a standing program whose scope covers this subject. Described, never endorsed.
— US —
USDA NIFA. The federal competitive agricultural research agency, funding work across every grain this directory maps. NIFA · Verified 2026-08-26
Brewers Association. Industry-funded research money aimed at beer rather than agriculture — the rarest kind in this directory. Research grants · Verified 2026-08-26
ASBC Foundation. The society's funding arm, supporting brewing science and graduate students in it. ASBC · Verified 2026-08-26
Pennsylvania Malt and Brewed Beverage Industry Promotion Program. State brewing money; appears on the internal and external enzyme pages for the same reason. Program page · Verified 2026-08-26
USDA NIFA — SBIR/STTR. The small-business route; the realistic path for a brewery rather than a university to fund fermentation work. SBIR/STTR · Verified 2026-08-26
SARE — Sustainable Agriculture Research and Education. NIFA-funded, four regional programmes; its Producer Grants fund on-farm trials including value-added products. SARE grants · Verified 2026-08-26
Master Brewers Association of the Americas. Technical body whose district programming and publications carry fermentation practice. Verified 2026-08-26
— International —
Australian Research Council. Public funder behind the Queensland proteomics work identifying the α-glucosidase that shapes sorghum wort. The preprint · Verified 2026-08-26
Seven funders. Only one — Pennsylvania's malt and brewed beverage programme — has a traceable award to gluten-free fermentation specifically. As with the enzyme pages, the money that could fund this work exists; what is missing is anyone pointing it here.
5. Suppliers & Industry — who propagates and sells the yeast
Described, never endorsed. This page's own framing notes that the commercial layer here is unusually open — yeast houses publish strain data, trial results and technical notes far more freely than enzyme producers do, which makes this one of the better-documented corners of gluten-free brewing.
— US strain houses —
Omega Yeast Labs — Chicago, Illinois. Liquid and dry brewing strains, publishing cell counts per pitch (150–225 billion cells) — the kind of specification a gluten-free brewer planning around a low-FAN wort needs. Strain range · Verified 2026-08-26
White Labs — San Diego, California. Liquid strain house with a published catalogue and analytical services; already referenced on this site's own yeast pages. Comparison chart · Verified 2026-08-26
Wyeast Laboratories — Odell, Oregon. The other long-standing US liquid strain house, referenced across this site's brewing-process pages. Comparison chart · Verified 2026-08-26
Imperial Yeast — Portland, Oregon. US liquid strain house selling into both craft and homebrew channels. Cross-reference chart · Verified 2026-08-26
— International strain houses —
Lallemand Brewing — Canada/Denmark. The dry-yeast major; publishes strain technical data sheets with attenuation ranges and nutrient guidance. Comparison chart · Verified 2026-08-26
Fermentis (Lesaffre) — France. The other dry-yeast major, and the most likely first strain a small gluten-free producer reaches for. Comparison chart · Verified 2026-08-26
Escarpment Laboratories — Guelph, Ontario. Liquid strain house publishing unusually detailed strain data and technical notes, including non-Saccharomyces cultures. Verified 2026-08-26
Bootleg Biology — Kentucky. Wild and non-Saccharomyces culture supplier; the commercial route to the organism classes this page's literature identifies in traditional sorghum beer. Verified 2026-08-26
Berkeley Yeast — California. Engineered brewing strains; relevant because aroma compounds this page's literature finds missing from sorghum beer are exactly what engineered strains target. Verified 2026-08-26
— The distribution layer —
Northern Brewer. US homebrew and small-scale supplier carrying the full strain-house range — the practical route by which a gluten-free homebrewer obtains yeast. Yeast catalogue · Verified 2026-08-26
MoreBeer / Homebrewing.org. US supplier channels carrying the full strain-house range for small-scale producers. Yeast catalogue · Verified 2026-08-26
Brewstock. Publishes a cross-supplier yeast comparison chart mapping equivalent strains across White Labs, Wyeast, Omega and Fermentis — the closest thing the field has to a strain concordance. The chart · Verified 2026-08-26
6. Organizations & Events — methods bodies, trade organizations, and the field's calendar
— US —
American Society of Brewing Chemists (ASBC) — founded 1934. Carries Budner's sorghum fermentation work in its annual meeting proceedings, and its official methods are the analytical language this subject is reported in. ASBC · Verified 2026-08-26
Brewers Association. The US craft trade body, and the funder of brewing-science research grants named above. Research grants · Verified 2026-08-26
Master Brewers Association of the Americas (MBAA). The other US technical brewing body; its district meetings and technical quarterly are where fermentation practice is argued rather than published. Verified 2026-08-26
Institute of Brewing and Distilling (IBD). The international technical body; publishes the Journal of the Institute of Brewing, which carries the maltose-transport and protease-aroma work indexed here. Verified 2026-08-26
American Homebrewers Association. The route by which fermentation technique reaches the practitioners doing most gluten-free experimentation, per this directory's homebrew wing. Verified 2026-08-26
Cornell Craft Beverage Institute — brewing extension. Analytical lab services and training available to producers, not only to researchers. Extension · Verified 2026-08-26
— Events —
Kansas State Brewing and Fermentation Science course. A three-day programme in brewing science, technology and sensory analysis. The course · Verified 2026-08-26
ASBC Annual Meeting. Where the Coastal Carolina sorghum work first appeared in 2017, before any of it reached journals. 2017 proceedings · Verified 2026-08-26
7. Literature & Datasets — the anchor works, the methods, and the published data
— The site's own reviewed evidence —
Budner et al. (2024), reviewed on this site. Our own read of the yeast-strain volatiles study, held as a research note rather than a directory entry. The review · Verified 2026-08-26
The production QA log, 2014–2017. This site's own multi-year production record — the fermentation history behind the guidance on the brewing-process pages. The log · Verified 2026-08-26
LCBO finished-beer certificates. Third-party analysis of finished gluten-free beer, including the fermentation outcomes a lot report would have to carry. The certificates · Verified 2026-08-26
— Yeast strain and aroma —
Budner et al. (2024), Targeted Study of the Effect of Yeast Strain on Volatile Compounds Produced in Sorghum Beer. Foods 13(22):3626. The central finding of this page: the same recipe brewed with four ale yeasts on sorghum extract and on barley extract: from day 3 onward the sorghum beers ran significantly lower across all nine measured aroma compounds — and changing the yeast strain did not significantly change that on either grain. doi:10.3390/foods13223626 · PMC11593854 · Verified 2026-08-26
Statistical Significant Differences between Aroma Profiles of Beer Brewed from Sorghum (2021). Beverages 7(3):56. The earlier study from the same group establishing that the sorghum/barley aroma gap is real and measurable, before the 2024 work tested whether yeast could close it. The paper · Verified 2026-08-26
Investigation of Millet-Based Beer Fermentation and the Volatile Compounds Formed (2026). Beverages. The same comparative method extended to millet — the second gluten-free grain to get controlled fermentation-aroma data. doi:10.3390/beverages12030037 · Verified 2026-08-26
— Nitrogen: the defining constraint —
Impact of Wort Amino Acids on Beer Flavour: A Review (2018). Fermentation 4(2):23. The link between what the yeast is fed and what it produces: wort amino acids are the precursors of the flavour-active compounds beer character is made of. The review · Verified 2026-08-26
Yeast: the soul of beer's aroma — a review of flavour-active esters and higher alcohols produced by the brewing yeast. Applied Microbiology and Biotechnology. Higher alcohols arise chiefly through the Ehrlich pathway, from leucine, isoleucine, valine and phenylalanine; those alcohols are then esterified into the acetate esters that carry beer aroma. The review · Verified 2026-08-26
Lin et al. (2022), Towards lager beer aroma improvement via selective amino acid release by proteases during mashing. Journal of the Institute of Brewing. Demonstrates the intervention the mechanism implies — use proteases in the mash to release amino acids, and aroma improves. doi:10.1002/jib.682 · Verified 2026-08-26
— Sugar order and uptake —
Yeast Carbon Catabolite Repression. The reference account: glucose represses the genes yeast needs to use other sugars, and the transporters themselves are degraded in its presence. PMC98918 · Verified 2026-08-26
Rautio (2003), Maltose Transport by Brewer's Yeasts in Brewer's Wort. Journal of the Institute of Brewing. How uptake actually behaves under wort conditions rather than in defined media. The paper · Verified 2026-08-26
Expression patterns of MAL genes and differential maltose and maltotriose transport rates in two S. pastorianus yeasts (2024). Applied and Environmental Microbiology. Strain-level variation in the transporters glucose represses — the genetic layer under the sugar hierarchy. The paper · preprint · Verified 2026-08-26
Influence of ammonia and lysine supplementation on yeast growth and fermentation with respect to gluten-free type brewing using unmalted sorghum grain. International Journal of Food Science and Technology 55(2). Tested supplementation directly: diammonium phosphate improved fermentation performance through better maltose and maltotriose uptake and faster gravity reduction. The practical answer to a low-FAN wort, measured rather than asserted. The paper · Verified 2026-08-26
Yeast fermentation of sorghum worts: influence of nitrogen sources. University of Pretoria. The standing thesis-level treatment of the nitrogen question on this grain. Repository record · Verified 2026-08-26
— Findings that change the question —
Proteomics and Metabolomics Reveal that an Abundant α-Glucosidase Drives Sorghum Fermentability for Beer Brewing (2023). The peer- reviewed publication of the Queensland work. Sorghum wort carries more glucose than barley wort, and both α- and β-amylase were considerably less abundant in sorghum wort than in barley wort — yet the wort still ferments, because an abundant α-glucosidase is doing the work. Sorghum's fermentability does not come from the enzymes sixty years of sorghum malt science has been measuring. PubMed 37821127 · the preprint · Verified 2026-08-26
Impact of mashing on sorghum proteins and its relationship to ethanol fermentation (2008). Kansas State. Across nine sorghum cultivars, mashing itself reduced in vitro protein digestibility considerably: disulfide-cross-linked polymers form during the mash, and the proteins build "highly extended, strong web-like microstructures." Cross-linking tracked directly with reduced conversion efficiency. The nitrogen this page needs is not merely scarce in the grain — the mash actively locks it away. PubMed 18197621 · the thesis · Verified 2026-08-26
Malting characteristics of finger millet, sorghum and barley. β-amylase activity in the Musama finger millet malt reached 301.6 U/mL — far above sorghum malt — and mashing sorghum malt together with Rwandan finger millet malt produced fermentable sugars, maltose in particular, at twice the level of pure sorghum malt. One gluten-free grain supplying the enzyme another lacks. The study · Verified 2026-08-26
Sorghum Starch and Protein Digestibility: Mechanisms, Modifications, and Health Implications (2026). The current review of the kafirin cross-linking mechanism — β- and γ-kafirins, high in cysteine, forming disulfide polymers that encapsulate the α-kafirins and resist proteolysis. doi:10.3390/foods15101681 · Verified 2026-08-26
Malted finger millet is an effective and economical adjunct in brewing. The adjunct case for finger millet, stated in the brewing literature. The paper · Verified 2026-08-26
Suitability of unmalted finger millet from China for beer brewing (2025). Journal of the Science of Food and Agriculture. The unmalted route for the same grain. doi:10.1002/jsfa.14388 · Verified 2026-08-26
— Why the sugars differ —
Proteomics and metabolomics reveal an abundant α-glucosidase drives sorghum fermentability for beer brewing. University of Queensland. The mechanism behind this page's framing: sorghum wort is glucose-forward rather than maltose-forward because of an abundant α-glucosidase, not because of its amylases. Sugar uptake order and attenuation behaviour follow from that. The preprint · Verified 2026-08-26
— Beyond Saccharomyces —
Identification of non-Saccharomyces yeast strains isolated from local traditional sorghum beer produced in Abidjan district (Côte d'Ivoire) and their ability to carry out alcoholic fermentation (2022). Identified Issatchenkia orientalis and Pichia kudriavzevii in traditional sorghum beer, with I. orientalis assessed as suitable for sorghum beer production. Strains isolated from the tradition rather than from a catalogue. PMC9235157 · Verified 2026-08-26
Michel et al. (2016), Pure non-Saccharomyces starter cultures for beer fermentation, with a focus on secondary metabolites and practical applications. Journal of the Institute of Brewing. The reference review for using these organisms deliberately. doi:10.1002/jib.381 · Verified 2026-08-26
The non-Saccharomyces yeasts as novel starter cultures to innovate beer brewing (2025). The current state of the same question. The review · Verified 2026-08-26
— Gluten-free brewing, broadly —
Assessment of brewing attitude of unmalted cereals and pseudocereals for gluten-free beer production (2022). Food Chemistry. Compares the brewing behaviour of the unmalted gluten-free grains this directory maps. PubMed 35257999 · Verified 2026-08-26
Production of Gluten-Free Craft Beers of High Antioxidant and Sensory Quality. Finished-beer outcomes for gluten-free craft production. PMC12841363 · Verified 2026-08-26
How the field connects — documented links between the entries above
Every connection carries its own evidence link — no inferred relationships, no speculation.
The FAN problem is funded, in Pennsylvania, right now. Penn State holds a $53,514 award explicitly aimed at producing sufficient fermentable sugars and free amino nitrogen from unmalted gluten-free grain — and its funder is the state brewing-promotion programme listed in this page's own Funders section. The one US public funder pointed at brewing has already been pointed at this page's defining constraint. It is the counter-example to the gap this directory keeps recording. The grant · the programme
A mash change can remove the enzyme purchase entirely. Penn State's ExGM decoction procedure reaches high fermentable-sugar concentrations from gluten-free malts without enzyme supplementation. Read against the external enzymes page, which maps an industry built on dosing, this is a process answer to a purchasing problem — and it decides what the yeast is handed. The procedure · external enzymes
The instruments exist at three US universities that already appear across this directory. Cornell runs a pilot brewery and a craft beverage analytical lab; Oregon State's research brewery measures diacetyl, esters and foam stability; Kansas State teaches brewing and sensory analysis. Penn State, Kansas State and UC Davis each appear on five or six pages of this directory already. The capacity to answer the aroma-gap question is distributed across institutions this site has been citing all along. Cornell · Kansas State · Oregon State
Sixty years of sorghum malt science has been measuring the wrong enzyme. Diastatic power measures amylase activity. SABS 235 codified it in 1970, the Novellie/CSIR assays invented it in the 1950s, and the SDU became South Africa's official trading unit for sorghum malt — malt is bought and sold on it. But the 2023 proteomics found α- and β-amylase considerably less abundant in sorghum wort than barley wort, with fermentability driven instead by an abundant α-glucosidase. If that holds, the entire measurement tradition is quantifying an enzyme that is not doing the decisive work — and this site's own evaluation methods critique, which argues the field kept using instruments after the question changed, has a mechanism behind it rather than only an argument. The 2023 study · SABS 235 · the Novellie assays
The mash creates the nitrogen shortage it is blamed for. Gluten-free wort is described everywhere — including on this page — as inherently FAN-poor. But across nine sorghum cultivars, mashing itself reduced protein digestibility considerably: disulfide-cross-linked polymers form during the mash, kafirins build web-like microstructures, and the degree of cross-linking tracked directly with lost conversion efficiency. Some of the nitrogen deficit is not a property of the grain at all — it is manufactured by the process, in the vessel, before the yeast is ever pitched. That reframes every downstream remedy on this page: supplementation treats a symptom the mash produced. The mashing study · kafirin cross-linking · the supplementation trial
A gluten-free grain can supply the enzyme another gluten-free grain lacks. Finger millet malt reached β-amylase activity of 301.6 U/mL, far above sorghum malt — and mashing the two together produced twice the maltose of sorghum malt alone. The entire external enzymes industry exists because sorghum cannot convert itself. Here the answer is not a bottle and not barley: it is a second gluten-free grain, malted. It is also the one route on this page that requires no purchase, no patent and no supplier. The malting study · millet directory · external enzymes
The aroma gap and the nitrogen gap may be the same gap. Higher alcohols come chiefly from the Ehrlich pathway — yeast stripping the amino group from leucine, isoleucine, valine and phenylalanine, and the leftover keto acid becoming an alcohol. Those alcohols are then esterified into the acetate esters that carry beer aroma. So the aroma compounds the 2024 study found depleted in sorghum beer are, in large part, made out of wort amino acids — and gluten-free wort is chronically short of exactly those. That would explain the study's negative result mechanistically: no strain can build esters from precursors the wort never supplied. It is a hypothesis, not a finding — but it is directly testable, and the test is cheap: supplement FAN, then re-run the same nine-compound panel. Lin's protease work is the same logic applied at the mash. Ehrlich pathway review · wort amino acids and flavour · protease-released amino acids · the negative result
A glucose-forward wort may sabotage its own fermentation twice. Sorghum wort is glucose-forward because of an abundant α-glucosidase. But glucose is not merely the sugar yeast prefers — it actively represses the machinery for using the others: MAL genes are switched off in its presence, and the α-glucoside transporters already made are rapidly degraded. A standard barley wort runs roughly 1:5:1 glucose:maltose:maltotriose. Shift that ratio glucose-ward and the grain delivers less maltose and suppresses the yeast's ability to take up what maltose there is. This may be why the supplementation trial's measured benefit showed up specifically as improved maltose and maltotriose uptake rather than as faster glucose use. Catabolite repression · maltose transport in wort · the α-glucosidase · the supplementation result
Every published attenuation figure was measured on a wort nobody here is using. Strain houses publish apparent attenuation ranges, and a cross-supplier concordance chart maps strains as equivalents across White Labs, Wyeast, Omega and Fermentis. Those figures are determined in all-malt barley wort at roughly 1:5:1 sugar ratio. Sorghum wort is glucose-forward, and glucose ferments faster and more completely than maltose — so a gluten-free brewer specifying a strain on its published attenuation is planning against a number generated on a substrate they are not brewing. We have found no strain house publishing attenuation determined on gluten-free wort. The best-documented commercial layer in this directory is documented against the wrong grain. The concordance chart · wort sugar ratios · the α-glucosidase
Yeast selection cannot fix a wort problem. The controlled test ran four ale strains across sorghum and barley extract: the sorghum beers ran significantly lower on all nine aroma compounds from day 3, and strain choice did not significantly change that on either grain. The practical consequence is uncomfortable — the most common lever a brewer reaches for when a gluten-free beer tastes thin is the one lever this study says will not move it. The aroma character is set upstream, in the wort. The study · our review
A negative result is the most useful thing this page carries. Most of this directory maps what a field found. The 2024 study's value is what it ruled out — and ruling something out is rarer and harder to publish. That is also why a statistician is listed among its authors above. The study
The nitrogen problem has a measured answer, not just a diagnosis. Gluten-free wort runs chronically FAN-short, and unmalted sorghum grain carries very low FAN. Supplementation was tested directly: diammonium phosphate improved maltose and maltotriose uptake and sped gravity reduction. This page's constraint is documented and addressed, which is more than most constraints in this directory can say. Supplementation study · the nitrogen thesis
An enzyme decides what the yeast is handed. Sorghum wort is glucose-forward rather than maltose-forward because of an abundant α-glucosidase — not because of its amylases. The grain's sugar profile, and therefore the yeast's uptake order and attenuation behaviour, are set by an enzyme mapped on the internal enzymes page. The two pages describe one continuous mechanism. The proteomics · internal enzymes
Grown enzymes make the nitrogen that bottled enzymes cannot. Koji mould secretes proteases alongside amylases, and the sorghum koji study measured 24% more FAN. The FAN deficiency this page names as a defining problem has a conversion-side answer that the external enzymes route structurally cannot provide. Koji & grown enzymes · the 2017 study
The tradition already isolated strains this page would have to buy. Non-Saccharomyces yeasts recovered from traditional Ivorian sorghum beer — Issatchenkia orientalis, Pichia kudriavzevii — were assessed as capable of carrying the fermentation. The organisms suited to gluten-free grain may already exist in the beverages mapped on the traditional fermentation page, rather than in a catalogue. The isolates · non-Sacch review
This is the best-instrumented question in the directory, and the instruments are pointed elsewhere. Oregon State's research brewery measures diacetyl, fermentation esters, foam stability, package gases and haze as routine. Those are exactly the measurements the 2024 aroma gap demands — and no gluten-free programme we have found runs them. OSU facilities · the aroma gap
The commercial layer here is unusually open, and that is a finding. Yeast houses publish strain data, attenuation ranges and technical sheets; a cross-supplier concordance chart exists mapping equivalent strains between White Labs, Wyeast, Omega and Fermentis. Nothing comparable exists for enzymes, where the external enzymes page records activity units that are not disclosed per lot. The concordance chart · external enzymes
Millet is getting the sorghum treatment, four years later. The comparative fermentation-aroma method that produced the sorghum findings has now been run on millet. It is the second gluten-free grain with controlled fermentation data — and the sixth still has none. Millet study · the millet directory
Research gaps — where the field's coverage runs out
Two US groups carry this subject, working different halves of it. Coastal Carolina with Florida produced the aroma-gap evidence — 2017 proceedings, the 2021 aroma paper, the 2024 strain study. Penn State works the nitrogen and mashing side under a funded grant. A first draft of this section claimed only one group existed; a search of the universities that recur across this directory disproved it, which is recorded here rather than quietly amended.
Nobody has re-examined sorghum malt specification against the α-glucosidase finding. If fermentability is driven by α-glucosidase rather than amylases, then diastatic power — the parameter sorghum malt is traded on — may not predict what a brewer actually gets. We have found no work proposing a replacement or corrected specification.
The finger millet blend has not been tested for gluten-free brewing. The doubled-maltose result came from sorghum-plus-finger-millet malt. Both grains are gluten-free, so the combination is a complete gluten-free conversion route on its face — but we have found no study running it as gluten-free beer, and no gluten-free producer using it.
The aroma gap now has a candidate explanation and no test. The Ehrlich pathway makes wort amino acids the precursors of the very compounds found depleted, and gluten-free wort is amino-acid short. That hypothesis is stated in the edges above. What does not exist, so far as we can find, is the experiment: nobody has supplemented FAN in a gluten-free wort and re-measured the volatile panel. It is a single-variable trial on equipment three US universities already own.
Nobody has measured whether glucose-forward wort represses maltose uptake in practice. Catabolite repression is textbook, the α-glucosidase finding is published, and the supplementation trial's benefit appeared in maltose uptake — but we have found no work joining them on a gluten-free wort. The sugar ratio at which repression starts mattering for these grains is unmeasured.
Strain attenuation on gluten-free wort is unpublished by anyone. Six strain houses publish attenuation ranges; none we found determined them on anything but barley wort. This is the cheapest gap on the page to close and the one most likely to be closed by a supplier rather than a university.
The aroma gap is measured but unexplained. We know sorghum beers run lower across nine volatile compounds, and we know yeast choice does not close it. We have found no work identifying why — whether it is precursor availability, nitrogen, lipid content, or something else. The next question is obvious and unasked.
Six of eight grains have no controlled fermentation data. Sorghum has it; millet now has it. For rice, buckwheat, corn, teff, fonio, quinoa and amaranth we have found no equivalent controlled comparison of fermentation behaviour or volatile formation.
One funder has been pointed at this, and it is a state programme. Pennsylvania's malt and brewed beverage programme funds the Penn State work on fermentable sugars and free amino nitrogen. The federal programmes listed above — AFRI, the Brewers Association grants, the ASBC Foundation — carry no award to gluten-free fermentation that we could find. The gap is narrower than on the enzyme pages, and it is a state rather than federal exception.
Strain recommendations are absent where they would matter most. Yeast houses publish attenuation ranges and technical sheets, but we have found no strain guidance specific to low-FAN, glucose-forward gluten-free wort from any of the six suppliers listed above — the exact conditions their customers in this category will meet.
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Entries are added as they are verified, never to pad the count. A listing here is a map reference, not a citation. Corrections welcome — see Contact.