Abstract 029
The Effect of Trub on Fermentation
Tech. Quart., Master Brew. Assoc. Am. 23: 37-43, 1986
K.J. Siebert, P.H. Blum, T.J. Wisk, L.E. Stenroos, and W.J. Anklam
Slightly turbid worts are known to ferment more vigorously than those which are bright. This is manifested in a more rapid drop in apparent extract and a larger yeast crop of higher viability. The effect has generally been attributed to the stimulation of yeast growth by nutrients, particularly unsaturated lipids, in the trub. While the addition of some lipids produced stimulation in our experiments, an effect similar to that produced by the addition of trub was also found when other particles, including activated carbon or diatomaceous earth, were added to bright worts. It appeared possible that the effect of such particles might be to serve as nucleation sites for carbon dioxide bubble formation, resulting in a lower carbon dioxide concentration and a lessening of the normal carbon dioxide oversaturation and resulting inhibition. Measurements of carbon dioxide content during such fermentations showed lower levels in fermentations with added particles. It is concluded that a large part of the stimulatory effect of particles in the wort is caused by reduced carbon dioxide inhibition of yeast growth.
Back to K.J. Siebert home page | Back to publication list