Issue link: http://winesandvines.uberflip.com/i/144804
grapegrowing Table I. Lees management considerations •Must clarification, non-soluble solids level (NTU), •Primary or heavy compared to secondary lees or light lees, •Volume of lees, •Stirring compared to non-stirring, method, frequency and duration, •Type and size of vessel, •Duration of lees contact, •MLF, timing of MLF, •Timing and type of racking (protective or aerative), •SO2 timing and level of addition, •Frequency of barrel topping, •Use of lysated compared to fresh lees, lees products. Juice clarification and non-soluble solids Photo by Aaron Bennett, n avarro winery Extensive crushing of red grapes can result in a high level of non-soluble solids, mainly in the form of phenol compounds that remain in the fermentor. White juice is generally racked prior to fermentation to eliminate precipitated juice lees consisting mainly of grape particulate, tartaric acid, polysaccharides and protein tannin complexes. During yeast fermentation, the level of macromolecules continually rises, peaking at approximately 270 mg/L.M. Guilloux‑Benatier et al. found a relationship between the degree of must clarification and the amount of yeast macromolecules recovered in the wine.10 When the must was not clarified pre-fermentation, there was limited production of yeast macromolecules.12 However, mild must clarification, such as cooling for 12 hours, increased the amount of yeast-produced macromolecule production by an average of 76 mg/L, and heavier must clarification, such as bentonite fining, increased the production by about 164 mg/L. S. Boivin et al. found that the amount of mac- Removing lees from a 50hL oak oval following fermentation and aging eight months sur lie. Your source for informative technical books. ORDER TODAY! www.PracticalWinery.com and click BOOKSHELF 76 p r acti c al w i ne ry & v i n e yard august 20 13