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New Post on MLF Two Questions LONG was: Observations about MLF

Steve and others,

I could have almost written your post exactly as you did and signed it, knowing that is precisely my experience with whites (gewurztraminer, riesling, pinot grigio and a variety called geisenheim). Perhaps the only exception to your post is that I have not made a serious attempt at really fine filtration. Due to the fact that I have a Buon Vino Superjet as you do, I believe we are limited to .5 microns. I will now use this routinely on my whites although the medium filter seemed to clear my wines more than adequately. I guess the real issue is stabilization.

Like you I tried the lysozyme route and had mixed results even when generous doses were used. Man does that stuff foam when added to the must!!! This year I plan to be a little more agressive with the SO2 maybe taking it up to 50 ppm's although reluctantly. My philsophy has been to minimize SO2, one of the advantages IMHO of home winemaking.

Apart from sterile filtration and the need to purchase more equipment or the use of sorbate which I do not like, I am pretty well resigned to the fact that we have oenococcus all over our cellar and about all I can do is try to minimize the problem. I rarely have ML in bottles as I bulk age my whites for at least a year in glass before bottling and if it's going to go through ML it usually happens by then.

I am purchasing a chromatography kit as there is some guesswork when a wine is fermented in our cool basement as that can drag on for a long time especially the last phase from 1.000 to 0.992.

Two questions:

1) When is it a good time to sulfite for bulk aging in whites you do not want to undergo MLF and at what levels. When I wait till the alcoholic fermentation is pretty well complete I am concerned that MLF is already underway. I usually start with juice that is in the 20ppm range at the time of yeast fermentation so I am thinking by the time the SG is around 1.000 I should probably up it to around 40 or 50 ppm's.

2) I understand there is a Lalvin strain that is recommended for aromatic wines. I would be interested in any experience with this agent.

Any thoughts from the above two questions would be appreciated.

Glen Duff

Reply to
Glen Duff
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For whatever it's worth, I've had reasonably good luck with lysozyme. Usually I get an immediate precipitate and I know that, at the very least, "something" is happening. About 2 months ago I began a batch of voignier in a cool 55 degree cellar. I treated it immediately with lysozyme. Last night, after the primary fermentation was completed, I racked and, just for the hell of it, I re-treated with lysozyme (for exactly the reasons that you've stated). But this time, I got absolutely no precipitate, so maybe the initial treatment actually worked.

Lee

Reply to
LG1111

Lee and All, Lysozyme is a protein and like other proteins (egg white, gelatin, etc) it reacts with phenols and precipitates. I suspect your first addition drooped out what little tannin there was in the wine. There wasn't much tannin left, so the second addition didn't cause a significant precipitate. Lum Del Mar, California, USA

Reply to
Lum

Hi Glen

Comments interspersed:

If you look up "living conditions" for ML Bacteria, it will tell you what conditions they require and what conditions they are unable to tolerate. Generally, they cannot tolerate_too_much acid, _too_much alcohol, or _too_much molecular SO2. These things are then the vulnerabilities that can be used to control this bacteria. Too much acid and/or alcohol presents us with "balance" problems, so the usual method of controlling MLB is through the use of an "aseptic" level of molecular SO2.

Sorbate inhibits yeast. It does_not_ inhibit MLB. In fact, MLB will consume sorbate resulting in the "geranium" effect we so often hear about.

Since MLF can and does occur in_parallel_with the yeast fermentation, you must start your SO2 regimen from the very beginning. (even before the yeast is added) To do this you must establish an initial "aseptic" level in the must. MLB has a much lower tolerance for molecular SO2 than does the commercial yeasts we use, so there is no problem with conducting a normal ferment.

It probably is.

The "aseptic" (molecular) level of SO2 is effected by the pH of the wine. So working blindly with only "free SO2" numbers just doesn't hack it. You will need to achieve a_minimum_level of 0.8 ppm_molecular_SO2 if you hope to control this bug.

In addition. You will find that_most_ of the initial addition of sulfite gets either bonded or is blown off during the ferment. Thus it requires a further addition of sulfite at first post ferment exposure to get the level back up to "aseptic". So long as this "aseptic" level is thereafter maintained in the wine (up to and including the bottling step), there is no risk that MLF will occur in that wine. HTH

Frederick

Reply to
frederick ploegman

Glen,

You should sulphite as soon as the fermentation ends (which would be < SG 1.000). Sulphiting during fermentation is pointless (and potentially harmful) since all the SO2 added will simply bind to acetaldehyde. I recommend you also give the must a decent dose of SO2. Of course, there will be a small window of opportunity for MLB during fermentation (when SO2 levels are very low due to binding & "blow-off") and you can try and control them with a low temperature (wouldn't you be doing a cool ferment with Gewurz and Riesling anyway?).

HTH, Ben

Improved Winemaking

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Reply to
benrotter

Thanks Frederick & Ben for your helpful comments.

Ben, You're right the temperature of my fermentation is quite cool and my Gewurz, Riesling and Pinot Grigio are nearly finished fermenting, now down in the 1.000 range. I just added SO2 to bring the level up to 0.8 ppm molecular as based on the pH of each, ranging from 3.33 down to 3.22.

Thanks again to both of you.

Glen Duff

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snipped-for-privacy@yahoo.co.uk wrote:

Reply to
Glen Duff

Wouldn't it be better to wait with the SO2 addition until the wine is really finished fermenting (assuming the intention is to ferment to dryness)? I thought that the binding with aldehydes would happen even when the wine is under 1.000 as long as it's still actively fermenting (which most wines are).

Pp

Reply to
pp

Wouldn't it be better to wait with the SO2 addition until the wine is really finished fermenting (assuming the intention is to ferment to dryness)? I thought that the binding with aldehydes would happen even when the wine is under 1.000 as long as it's still actively fermenting (which most wines are).

Pp

Reply to
pp

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