啤酒高浓度发酵酵母的扩培方式

为获得适合高浓度啤酒发酵的扩培方式和性能优良的酵母培养液,研究了种子扩培方式对酵母活力和发酵性能的影响。采用不同扩培的种子液进行20°P麦汁发酵,测定了发酵过程中细胞密度、α-氨基氮质量浓度、还原糖质量浓度、CO2失重量、酵母存活率及发酵度等指标。结果表明,扩培方式对酵母的发酵性能和存活率影响较大,其中经12°P麦汁进行一级种子扩培、16°P麦汁进行二级种子扩培的酵母在发酵过程中性能稳定,细胞存活率和发酵度高,这种扩培方式较适合20°P麦汁发酵。

The method of yeast propagation for beer high gravity brewing

Yeast activity and fermentation performance were studied to obtain the best method of yeast propagation and yeasts culture with high vitality used for high gravity brewing.During 20°P wort fermentation by Saccharomyces cerevisiae propagated in various gravity of wort,cell density,α-amino nitrogen concentration,reducing sugar concentration and attenuation degree were determined.The results demonstrated that the fermentation performances were different when yeasts were propagated in various gravity of wort.The yeast propagated in 12°P wort at the first level and in 16°P wort at the second level had stable fermentation performance,high vitality and attenuation degree,which was suitable for 20°P wort fermentation.