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> malolactic or other, fermentation going again after sugar gone
killroy
post Oct 13 2012, 05:57 PM
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Have a cyser OG 1.092 FG 1.0002 with Lavlin D-47. Racked to carboy 7 days ago at 1.0002. No airlock activiy no bubbles for 5 days. Now have significant airlock activity (1Xevery 10sec) and can see many bubbles rising. Is this malolactic fermentation or could it be more insidious bacteria doing their work. I can't smell any diacetyl.

I ran out and got some lysozyme to stop the geranium effect (which I now know happens only in conjunction with K-Sorbate). I do plan to backsweeten, but maybe in a year at bottling.

I have some K-metabisulfite as well.

If it is malolactic fermentation I think I will let it go. That way there will be no danger of geranium flavor/aroma when I do add the K-Sorbate.

If it is a different kind of bacteria that will ruin my batch I want to stop it ASAP. How do I know?

If I do want to stop this do I add lysozome and K-metabisulfite? Just K-metabisulfite? I've read conflicting reports about K-meta (that it just inhibits rather than kills bacteria). I also have a chest freezer that I can cold crash.

This post has been edited by killroy: Oct 13 2012, 06:18 PM
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fatbloke
post Nov 17 2012, 04:26 AM
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QUOTE(killroy @ Oct 13 2012, 10:57 PM) *
Have a cyser OG 1.092 FG 1.0002 with Lavlin D-47. Racked to carboy 7 days ago at 1.0002. No airlock activiy no bubbles for 5 days. Now have significant airlock activity (1Xevery 10sec) and can see many bubbles rising. Is this malolactic fermentation or could it be more insidious bacteria doing their work. I can't smell any diacetyl.

I ran out and got some lysozyme to stop the geranium effect (which I now know happens only in conjunction with K-Sorbate). I do plan to backsweeten, but maybe in a year at bottling.

I have some K-metabisulfite as well.

If it is malolactic fermentation I think I will let it go. That way there will be no danger of geranium flavor/aroma when I do add the K-Sorbate.

If it is a different kind of bacteria that will ruin my batch I want to stop it ASAP. How do I know?

If I do want to stop this do I add lysozome and K-metabisulfite? Just K-metabisulfite? I've read conflicting reports about K-meta (that it just inhibits rather than kills bacteria). I also have a chest freezer that I can cold crash.

Well, personally, I don't add sorbate without sulphite. Just adding sorbate on it's own is the way of getting geraniols.

Sulphites would prevent MLF anyway, as I understand that for MLF to take place, the batch has to be below 20 ppm and 1 campden tablet per gallon gives about 50 ppm.

The bubbles could be that when you've racked it, the liquid movement may have just removed enough of the dissolved CO2/carbonic acid to swing the pH high enough for it to gently start refermenting.

I'd just keep an eye on it and measure the gravity to see if it's dropping.

Infection of some sort is possible of course, but if you use a reasonable hygiene regime, then it's not as likely.

If it is some sort of bacteria, equally, it's usual to smell something bad or at least see signs of something in the batch, but given that you've had a 90 point drop, that equates to 12.2% ABV and from memory D47 is good for 14% ABV, so there's still some room for the referment to have started, plus I've read in a few places that once the batch goes over about 11% ABV, then the alcohol is the preservative and only the obvious infections like acetobacter will screw things up and you can taste and smell that easily enough.

As for what the sulphites actually do, they don't kill the yeast, they stun the cells, which is why it's used in conjuction with sorbate which prevents them from multiplying further. It seems that if you did want to keep the batch where it is, you'd have to cold crash it for a week or so, and then rack the cold brew onto the sulphites and sorbate - obviously not guaranteed to stop an active ferment but there's a fair bit of anecdotal evidence that it works - even if it does take time for the cold crash i.e. a batch put in the fridge/freezer at 1.010, will often measure 1.005 or even lower once it's been crashed and stabilised. It's not an "instant" stop.....

Never used lysozyme so don't know what it's properties are......
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