Using fed-batch fermentation in high-gravity brewing: effects of nutritional supplementation on yeast fermentation performance

To intensify the brewing process and increase the fermenter productivity, many breweries throughout the world have been embracing high-gravity brewing. However, increasing original wort concentration can cause a negative effect on yeast fermentation performance. This study focused on the application of fed-batch fermentation in high-gravity brewing. High gravity worts of 24 o Bx (using 30% high maltose syrup adjunct) supplemented with yeast extract or mixture of yeast extract and Tween 80 were used as feeding-media in fed-batch cultures. As a results, the nutrients supplemented to feeding media improved the yeast fermentation performance. Especially, the supplementation of 0.25% (w/v) yeast extract and 0.8% (v/v) Tween 80 to the feeding-medium not only reduced the primary fermentation time, but also increased the ethanol concentration of the fed-batch culture in comparison with the fed-batch culture without this supplementation to the feeding- medium.