Miniaturizing the fermentation assay: Effects of fermentor size and fermentation kinetics on detection of premature yeast flocculation

摘要: This article reports on fermentation assays used to test the fermentability of malt, especially malt implicated in premature yeast flocculation (PYF). No standard small-scale method currently exists. The current study involved 12°C fermentations with three vessel configurations: a 4.4-cm high spectrophotometer cuvette, 12.5-cm tube, and 122-cm "tall" tube fermentor. Worts tested were made from control PYF malts. We included our experiments Jibiki associates, using wort supplemented 4% glucose fermented at 21°C. decline Plato values (or real extract) was fit sigmoidal model. model parameters fermentor height estimate CO 2 evolution average shear rates. It confirmed that both speed are major independent variables determining agitation within fermenting wort. In examining data, it is evident did not stay equally suspended all vessels. When 12°C, fell out suspension rapidly cuvette fermentors. tall tubes, remained as expected. 21°C had profiles similar but complete less than 72 hr. notable these could be distinguish between minimum rate required keep determined 4 7.5 sec -1 . Thus, when downscaling assay by reducing height, must increased maintain adequate reduced 15 mL, resulting labor, time, material costs.