sous voile (under veil) = production style using specific yeast. for barrel aging post-fermentation, barrel is not totally filled which leaves a gap. a thin yeast layer forms
voile = thin layer of yeast preventing/controlling oxidation of wine
flor == voile. same concept but flor is the spanish term
ouillé vs. sous voile. ouille = topped up = STANDARD WINEMAKING PRACTICE. topping up the barrels during aging to replace the angel share. this is called out by Jura winemakers to signal that this wine is the fresh style keeping fruit intact
fino sherry = also produced sous voile BUT FORTIFIED. thicker yeast layer (due to strain) that offers more protection from oxidation
acetalhyde = not acetic acid. this is an adelhyde that --> acetic acid next
vin jaune production style == jura white wine production style (sous voile)
understand
Jura wine styles take Vin Jaune as the north star (oxidative) which is the region's most famous product
Savagnin is almost exclusively grown in Jura. Vin Jaune is 100% Savagnin. Savagnin is high acid
Aldehyde notes = classic fruit browning oxidation notes (candied green apple / nuts)
Why voile forms? A specific film-forming strain of yeast (Saccharomyces) rises to the surface and multiply into a thick layer. Instead of sugar, these surviving yeast cells shift to an oxidative lifecycle. They feed on the wine's alcohol, glycerol, and the available oxygen in the headspace. That's why Savagnin (high acid) needs to be very ripe when harvested to alcoholmax post-fermentation since the voile feeds on the alcohol