Interactions Between Fermentation Temperature and Yeast Strain: Impacts on Polyfunctional Thiol Release and Beer Aroma
Bibliographic record
Abstract
The biotransformation and release of polyfunctional thiols (PFTs), including 3-sulfanylhexan-1-ol (3SH), 4-methyl-4-sulfanylpentan-2-one (4MSP), and 3-sulfanyl-4-methylpentan-1-ol (3S4MP), contribute to tropical fruit aromas in beer. This study examines the effect of fermentation temperature (15–30 °C) on PFT production across five commercial yeast strains. Pilot-scale beers were brewed with Cascade hops and analyzed for 29 aroma compounds. A strong temperature-dependent increase in 3SH (33–72%) was observed, with the lager yeast strain yielding the highest levels at the high-temperature condition (30 °C). However, sensory analysis indicated that elevated thiol concentrations alone did not enhance tropical aroma. Instead, increased levels of β-ionone, β-damascenone, acetate esters, and terpenoids at higher fermentation temperatures correlated with a more pronounced tropical character, particularly with the ale yeasts. These results highlight the intricate relationships between thiol levels and concurrent volatile compounds, emphasizing that elevated thiol presence alone does not directly translate to heightened tropical aromatic expression in beer.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".