|2018 ASVO Seminar; Fermentation- Converting research to reality|
|Modern Winemaking or:
“How I Learned to Stop Worrying and Love Oxygen” Dr Martin Day, Australian Wine Research Institute
|Although considered detrimental by many who exclude oxygen throughout winemaking, a beneficial influence can be achieved on style and prevention of undesirable sensory outcomes in both white and red winemaking. Subtle modulation in sensory properties can be induced by controlling passive oxygenation at berry rupture rather than with inert handling. Oxygenation during white fermentation can improve efficiency and minimise sluggish completion without significant change to aroma and flavour. Maximum stylistic impact occurs in red winemaking with oxygenation during primary fermentation, preventing development of negative mercaptans, obviating N-supplementation and softening tannin.
The mechanics of oxygenation depend on fermenter scale and cap management but comprise in-tank spargers or in-line devices during pump-overs. Gas choice is equally important, affected by workplace safety and product protection as much as efficiency. When, how-much, how-frequently and effect on simultaneous MLF remain key questions. Several early additions prove optimal for successful and efficient vinification with positive sensory outcomes.