Hydrogen Sulfide - DAP recommendation?

I'd try hitting it now with DAP if it's still fermenting. That and stirring up the bottom vigorously might do the trick. You don't really want to have to copper treat the wine if you can avoid it, although just stirring with a piece of copper pipe might be sufficient. Even if the odor goes away, be sure to keep the bottom stirred until you press, then settle overnight and rack off the sludge or that problem is likely to recur in this wine.

BTW, an extra shot of yeast has _nothing_ to do with this problem. It's either nutrient deficiency or free sulfur on the grapes from being dusted too late in the season.

Tom S

I did this with a Cabernet - adding 200 ppm DAP and 200 ppm Fermaid mid-way through the fermentation. I also stirred and punched down like crazy to get oxygen into the must. There was still some odor when the ferment was done, and I let it go until MLF completed - this was a big mistake since the H2S turned into disulfides. The lesson I learned is, don't be afraid of using copper (1% copper sulfate solution) - it's not a big deal, you know how much is going into the wine, and it can take care of a solvable problem before it gets to be a complex, difficult problem.

Ed

I couldn't agree more. People seem to be afraid of using copper, but when it's warranted, a very tiny amount will fix the problem so quickly and completely that it can seem like a miracle. If it's used in the recommended amounts using the proper procedure there is no health risk at all, you can get more copper from other sources in the diet than what's left in the wine after treatment and racking.

John

Hello All,

I used to be plagued with H2S problems myself until I adopted a ranck-and-return fermentation technique. What I realized is that most home winemakers (myself included) greatly underestimate the need for must nutrition and aeration during fermentation. Feed your yeast well with DAP and practice rack and return with aeration twice a day and you will never see H2S again and you'll be delighted with the results. I've read many books that recommend punching down or stirring "vigorously" to aerate the must when H2S is detected. The problem with this is that an actively fermenting must has a blanket of CO2 over it so it doesn't matter if you stir it till you pass out, you won't get much aeration. Best to pour back and forth between containers or better yet, invest in a food grade plastic tank and put a drain in it so you can drain, aerate, and pump over.

CHEERS!!

Aaron

Great info, thanks all for the recommendation(s). The DAP addition has helped a bunch.

James