Effect of malt wort, very-high-gravity malt wort, and very-high-gravity adjunct wort on volatile production in Saccharomyces cerevisiae

The metabolizing of carbohydrates during fermentation by brewing yeasts leads to the production of many flavor-active compounds, including esters and higher alcohols. A better understanding of their synthesis may lead to improved flavor control in brewery fermentations. Previous work using synthetic media has shown that metabolism of maltose results in production of lower levels of these volatiles compared to glucose and fructose. This study examined whether fewer volatiles would be produced when fermenting very-high-gravity adjunct worts compared to the levels obtained from fermentation of all-malt very-high-gravity wort. It was found that very high gravity wort which had 30% of very high maltose syrup added as adjunct produced significantly lower levels of esters and higher alcohols. Ethanol production was not affected, while viability remained elevated in cells fermenting the adjunct wort. Volatile production was not reduced to the same extent in all cases. Alteration of wort carbohydrate profile alone did not result in concurrent improved flavor matching for all volatiles measured; therefore, it is concluded that additional wort nutrient supplementation is required to achieve this.