Yeast Hulls (NUTREX 370) (also called cell membranes, yeast cell walls, yeast ghosts, or envelopes cellulaires) are the insoluble cell membranes left over after yeast autolysis and centrifugation to separate them from yeast extract. They are very beneficial to fermentations, adsorbing pesticide residues, toxic short-chain fatty acids (C8-10) and other inhibitory by-products. Yeast hulls also provide sterols and long-chain fatty acids to build healthy cell membranes that help delay alcohol toxicity. Yeast hulls are a key element in many nutrient blends, and are also added separately late in fermentation to stimulate stuck or sluggish ferments. The famed French enologist Dr. Pascal Ribereau-Gayon considered yeast hulls to be the most helpful product for preventing or treating stuck ferments. Nutrex 370 comes from the same procedure as T154, so it has VERY neutral sensory qualities, without cheesy odors or aggressive flavors that mar some other brands.