ML question & barrels

Thanks to Derek for his email question on barrel fermenting whites:

“Is it harder to finish malic fermantation (sp) in tanks than in barrels? People i’ve talked to say that ml fementations go naturally in barrels...and does it matter to the flavor, or is it just the change of the acids from malic to lactic?”

First, it’s not harder to finish ML fermentation in tanks rather than in barrels. Barrels seem to take ML fermentation faster, or “naturally” start ML ferm, usually because some of the ML bacteria is still present in the barrels from previous wines, and inoculates anything new that’s put into it afterwards.
In fact if you don’t want to have the wine go through ML fermentation (or only a partial fermentation of the malic acid) then it’s probably easier to avoid full ML conversion and/or arrest it when it’s left in tank.

As far as flavors produced, the tank ferment will tend to be "cleaner" expression of just the fruit without the oak flavors added. It really shouldn't have much effect the flavor of just the ML fermentation.
It could affect how the sur lies contributes flavor to the wine, as it's difficult to stir the lees up in the tank when compared to barrels.
Also the surface area of lees that's exposed to the wine (in tanks) may be much less than that in barrels, and can change the flavors and aromas of the wine.

I don't think it's appropriate to ascribe one way as superior to another, as it really depends on what the winemaker is trying to do. Personally I like barrel fermented Chardonnay wines, but prefer stainless fermented Sauv Blanc and Viognier to their barrel fermented counterparts.

Thanks again for the email. Please feel free to email any questions, or to suggest topics for discussion!

Cheers!