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What happened?

I have just had a batch of Riesling go all H2S on me, and I can't figure out why. Any help would be appreciated -

I used 150 lbs of ripe grapes, with just a touch of botrytis (no fuzzy grapes, though), from a local vineyard, who also grow for local commercial wineries. They claim that their pest control process only uses Sulfur prior to bud-break, 3 applications total. I got the grapes on a Friday, crushed them that afternoon, and let them sit on their skins overnight (14 hours total). 15 gallons of must, measuring

20 brix, .62 TA, 3.1 pH (that last might be off, I'm having trouble with my pH meter :-)). No sugar or acid adjustment. Added 15 campden tablets, and mixed as well as I could. Pressed in the morning, getting 6 gal free run, and 4.5 gal pressed juice, keeping them separate. Brought up each to 50ppm sulfite.

Started the yeast later that day, using two strains from Morebeer.com (QA23 and RHST), neither one being Montrachet, nor implicated in H2S production before that I know of. The RHST started better than the QA23, such that I stole a little of the float of the RHST to boost the QA23. They ran for about a day and a half without problems, then suddenly instead of a brown yeast cap, I suddenly had a white cap and a heavy rotten egg smell. It's at 16 Brix, and the sulfite level went down to about 25ppm.

Following one of the books I have, I've now bubbly-racked them both twice, and there is virtually no sludge on either of them. The smell is still there, and strong. If you blow the smell away, the juice tastes good. I'm afraid that it's probably a loss at this point. sigh...

However, any ideas on what to do to avoid this in the future? I'd be glad to answer any questions anyone has if it'll help figure out the problem.

Reply to
Rob
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The next step is to rack through copper. Get a length of 1/2 inch copper tubing from a hardware store and ream out the inside with sandpaper to remove any resin coating. Rack through this tube slowly with lots of aeration, then bring the sulfite levels up again. Alternatively, get a copper pot scrubber and rack through that.

This technique saved a batch of mourvedre that had developed disulfides, the next stage after H2S. It smelled like an onion field, but racking through copper did the trick. You should do the copper racking as soon as you can--today!--to prevent it from developing disulfides.

Rob wrote:

Reply to
ernie

Someone smarter than yerz trooly may want to verify this, but I thought I read ages ago that you could get H2S to preciptitate out with Bluestone aka Copper Sulphate. Anyone? Hmm?

Reply to
Bob

You heard right. Provided it is food grade.... not the tree root killer for your sewer line

Gene

Reply to
gene

A word of caution... You must be very careful when using copper to treat H2S. It is a heavy metal and can be toxic in large doses or in smaller doses over time. I suggest you try Bocksin which is a colloidal silica product that is very effective at removing H2S and is non-toxic.

CHEERS!

Reply to
Aaron Puhala

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