Malt Extract: Relationship of Chemical Composition to Fermentability¹

1 Presented at the 56th Annual Meeting, Ft. Lauderdale, FL, May 1990.

Abstract

Forty-four commercial malt extracts used in microbreweries, brewpubs, and/or home brewing were adjusted to 12°Plato and fermented at 14°C. Results were compared with those of an all-malt wort from a large Canadian brewery fermented under the same conditions. In general, the worts made from malt extracts contained lower utilizable free amino nitrogen (FAN) values, showed slower fermentation rates, and had darker colors than the brewery wort. The extracts with higher FAN fermented better than those with low FAN levels. The slow fermentation rates of some malt extracts that contained low initial levels of utilizable FAN could be improved by supplementation with assimilable nitrogen from yeast extract or the nitrogen (but not the carbon skeleton) from glutamic acid. The carbohydrate profiles of the malt extracts as determined by high-performance liquid chromatography showed considerable variation. It was possible to detect in the malt extracts the addition of, or adulteration by, lower cost adjuncts such as glucose syrup, invert syrup, liquid sugar, or high-fructose corn syrup.

• Adjunct
• Carbohydrate
• FAN
• Malt extract
• Stuck fermentation
• Utilizable nitrogen