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two questions about MLF

For the first season, I've been able to conduct really successful MLFs. I found that the "trick" was to use the powdered Chris Hansen ML bacteria, use a healthy dose of ML nutrient, and do it at a 78-80 degree temperature. Now, after about 6-8 weeks, a ML chromatogram shows no malic acid spots, but there are still occasional tiny bubbles in the carboy. The wines haven't been sulfited yet.

Should I expect the bubbles to COMPLETELY stop? I suspect that this won't happen, and I'm anxious to do a final racking and add some sulfite. So that's my first question: Do I have to wait for the MLF to COMPLETELY stop? Or will the sulfite do the job, or should I resort to lysozyme?

Secondly, I have a couple other batches of wine in various stages of their primary fermentations or completely finished which were never innoculated with ML and which were sulfited from the beginning. Just for the heck of it, I ran a chromatogram on those as well and while they have very obvious malic acid spots, they also have pretty prominent lactic acid spots. Does this mean that I have incomplete ML fermentations on those, or does lactic acid occur naturally?

Thanks, as always.

Lee

Reply to
LG1111
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When my wines get to that point, I hit it with SO2, top up and bung tight. If your wine is in a carboy, be careful about that last part though. Bung it too tight and a temperature shift can blow the bottom out of the carboy.

That's a very good question that I can partially answer. I suspect that you have spontaneous ML going on in that wine - especially if the pH is above

3.5.

Tom S

Reply to
Tom S

I was at a talk once by a guy who's a chemist and owns a store that sells all the fancy lab equipment to wineries. He said that the chromatography paper can only show malic spot when it's above certain, still significant concentration - don't remember the exact number. The rule of thumb he recommended was to wait for a couple of weeks after the spot first disappeared from the paper and then rack and sulfite.

Pp

Reply to
pp

That's true. Paper chromatography indicates malic acid concentrations above about 100 mg/l. Wines may continue to undergo MLF over 30 mg/l without showing any malic spot on the paper. Paper chromatography should not be considered a quantitative test, only a qualitative test. I agree with this chemists recommendations: wait a little before sulphiting.

Ben

Improved Winemaking

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Reply to
Ben Rotter

Lee, Wine contains little lactic acid before MLF. But, the yeast produces small amounts of succinic acid during fermentation. On a chromatogram, the succinic acid spots and the lactic acid spots are superimposed, so all wines show a lactic/succinic acid spot before MLF. Lum Del Mar, California, USA

Reply to
Lum

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