Diacetyl is produced by yeast as a byproduct of the amino acid synthesis they undergo to continue with the fermentation process. Diacetyl has a “buttery” flavor, which is undesirable in the vast majority of beer varieties. Further, diacetyl has a very low taste threshold, therefore extra care must be taken to ensure its elimination below this level before beer can be finished and sold. The ability for breweries to minimize the fermentation time and applicable rest times can translate into significant production increase and cost reductions. To accomplish this, initial fermentation parameters of pH and free amino nitrogen (FAN) and fermentation temperature will be varied, and final diacetyl content measured to determine optimum fermentation conditions. Diacetyl content will be measured by gas chromatography with headspace sampling and electron capture detection (ECD), with FAN measured using UV/Visible spectroscopy. The ECD method doesn’t require sample derivatization, while providing amply low limits of detection.

Minimizing diacetyl formation in beer by controlling fermentation parameters

253rd National Meeting (2017)

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