Extraferm® Halo Procedure
During fermentation, wine yeast produce several auto-toxic compounds such as ethanol, carbon dioxide and medium length chain saturated fatty acids (C6, C8 and C10) which inhibit sugar transport (Larue and Al, 1982; Salmon and Al, 1991). The objective of must detoxification is to remove these compounds and create more favorable conditions for yeasts growth activity. The use of a specific adsorbent property of yeast hulls is authorized to restart fermentation as it removes inhibitors (Lafon-Lafourcade and Al, 1984).
Yeast hulls are produced from the elimination of yeasts cytoplasmic contents by autolysis in controlled conditions, followed by centrifugation. Yeast hulls not only detoxify, but also provide nutrient and yeast "survival factors" such as fatty sterols and long chain unsaturated fatty acids. These compounds increase the restarting yeast strain viability at the end of fermentation.
HALO, an innovative process
Traditional yeast hulls can transmit a yeast odor to the wine, even when used at low dose rates (from 20 g/hl). Moreover, their effectiveness in detoxification is sometimes limited. DSM research developed an innovative production process, with the objective of obtaining highly adsorbent yeast hulls that would not transmit any odor to the treated wine even at high dose rates.
Dosages of up to 100 g/hl of Extraferm® can be used without any negative effects on the organoleptic quality of a wine.