[K&GB]

Hi everyone, this is the G partof K&GB. I know Ken has done all of the writing up til now, but I've been getting more and more involved in this new adventure and figured it was time to foray into this forum.


I have a couple of questions. We originally made a 23L aseptic juice Cabernet Sauvignon (not sure of the brand). It came without directions, so we were winging it and ran into a little problem. When it was about 5 weeks old, we tested it and noticed that it had an off odor. It's hard to describe (ok, hard to remember by now...lol), but it reminded me of mucky vegetation....you know, wet leaves and grass that have been decaying for a while. Ken thought it smelled a little like BBQ sauce. The wine also hadn't cleared at that point, so we added Super-Kleer. A few weeks later, the wine was clear and had lost almost all of that odor. We also put in KMeta when we did the Super-Kleer.


Now....we've got our MM Sangiovese going. We tested (and tasted) it at 3 weeks of age and it had the same foul odor as the Cab.Ken still felt it smelled like BBQ sauce and I made the distinct association to a vase of flowers that has just died where the water had not been changed for a week. Yep........it smelled like that stagnant, old water. We added KMeta and later treated with Super-Kleer. We then racked it 2 weeks later and it still has that same foul odor and frankly, a foul taste.


What can this be?!?!??!?!


Thanks for your imput.


Gina

[PeterZ]

I've had that happen to me. I have not identified a cause, but it fades with time, and decanting the wine and leaving it to breathe before drinking both work to get rid of it. To me the smell is "stewed greens."

[Wade E]

I have never run across this. I might try splash racking it to see if that gets rid of the smell. By any chance was this sitting on thick lees for some time over what is recommended?

[grapeman]

It sounds like you may have a slight 2-mercaptoethanol infection and can be the bi-product of some fermentations. They are called mercaptans and impart objectionable odors reminiscent of rotted manure or rotten onions. Very small amounts of copper sulfate or silver chloride can be used, but I would be reluctant because they are very small amounts. You could try the copper pipe trick. Use a well cleaned piece of new copper pipe and swirl it around in the wine for a wile. It sometimes binds the mercaptans and they precipitate out.


Maybe Peter can give you more information.

[K&GB]

Thanks Peter, Wade and Appleman. As Gina mentioned, both our reds have a bad smell and taste, although they both do seem to be fading with time. It's hard for me to describe, but to me it smells a bit like BBQ sauce (vinegar maybe?). Here are some variations from the directions, in case it matters. (The cab didn't come with directions) We added table sugar to both to bring the brix up to 23.5. We fermented a little on the hot side, around 80F or just under. With the Sangiovese, I missed the part of the directions where it said to retain the sediment when transferring to the secondary fermenter. Oh, and I moved the Sangiovese out into the cold after stabalizing, so it failed to clear with liquigel and siligel. I've used Super-Kleer on both now and it seems to have diminished the smell and taste somewhat. The Cab is less noticeable than the Sangiovese, but it's a few weeks older.


Funny, but I DID try to "splash" rackboth winesthis weekend by holding the hose up out of the carboy and letting it splash down the side.


I've heard of mercaptans, and I do have copper sulfate. But I'm reluctant to use it because of its toxicity. I also have no experience, and can't be sure that's what the problem is.


I was hoping to blend these wines during bulk aging and I had a whole scheme written out with different percentages and different sized containers. But I can't proceed until this distinctly unappealing taste goes away. For now, I'll just sit on both wines and check them every so often.


Unfortunately, my problems with these have made me reluctant to try anymore reds. It seems that the Sauvignon Blanc, Viognier, and Reisling are turning out so well by comparison. The whites smelled so good during fermentation also, but the reds never did. I was planning to do a Pinot Noir next, but now I may wait and see if the first two ever turn out to be drinkable.

[Wade E]

Im only on my 6th true red but havent encountered this and ope to never. Appleman, what causes this and what are the chances of this happening twice in a row?

[PeterZ]

My memory tells me that CuSO4 - copper sulfate - is allowed inlake and pondwater up to 5 mg/L without toxicity to fish. It is normally used to control algae. Unfortunately, at 5 mg/L a 23 L batch can only take 115 mg, and that is very hard to measure. I would not do it.


I have only had this happen once. The one time it happened was in the summer, so the higher fermentation temps might have been the cause. In any case, it is now completely gone from my merlot, and even at its worst an hour of breathing was sufficient to eliminate it from a bottle.

[grapeman]

I don't think I would want to trythe copper sulfateeither. Actually why not take a piece of #12 ground wire a couple feet long and stir the wine with it. I know others have done it with favorable results. I believe it doesn't need to be in the wine long to get rid of the odors. Just be sure the copper wire is clean and sanitized.

[Jack on Rainy]

K & GB, Interesting thread and you two seem to be interesting and curious wine makers. Please share your plans for blending. And, what were the kits you were successful with?
For constructive comment on your problem, I would hesitate using a copper pipe because the inside is so difficult to clean.


I might also ask Appleman if the wire should be free of the oxides on the surface of the wire. I am also interested in your answer to Wade's question on time on lees.

[K&GB]

Thanks everyone for your helpful input. I've pasted something from Lum Eiseman's tutorial (available under "Resources") regarding hydrogen sulfide and the use of copper sulphate to remove it. However, as I mentioned before, having never smelled it, I'm not certain my problem is actually hydrogen sulfide, nor am I comfortable using copper sulfate as a treatment. I'll leave that to professionals with experience and expensive diagnostic equipment.


What I plan to do is continue racking every few weeks, checking free SO2 and adding Kmeta as required to maintain roughly 30 ppm, and splashing the wine around during racking.


Jack, neither wine remained long on the lees. If anything, I racked them a bit early after confirming fermentation was complete. For instance, the Sangiovese directed 20 days before racking and stabilizing. Without referring to mynotes, I think I did it in 12-15 days. As for my blending plans. Those are on hold until I resolve the smell/taste problem. But I'd be happy to post my "Supr Tuscan Blending Scheme" when I get back home. It's on my home computer.




HYDROGEN SULFIDE


Hydrogen sulfide gas (H2S) produces the familiar "rotten egg" smell. This noxious gas can be produced by yeast during fermentation. H2S can also be formed from decaying yeast cells when wine is left on gross lees for a long time. Most people can detect one part per million of this gas, so very small quantities of hydrogen sulfide can completely spoil a fine wine. Most often, hydrogen sulfide is produced from elemental sulfur during fermentation. The sulfur enters the juice as a residue on grapes treated with a sulfur spray (to control powdery mildew). The sulfur is converted into hydrogen sulfide by the reducing atmosphere of the fermentation.


Sometimes hydrogen sulfide is produced by yeast when the grapes contain no residual sulfur. Here, the smell is usually detected near the end of fermentation. During the later part of fermentation, yeast often runs short of some needed material, and hydrogen sulfide can be produced when yeast does not have enough nitrogen, micro nutrients or vitamins. Hydrogen sulfide is produced when fermentations do not contain enough pantothenic acid, but hydrogen sulfide can be produced any time yeast is subjected to stressful conditions.


Winemakers often add extra nitrogen and micro nutrients to their fermentations specifically to avoid the production of hydrogen sulfide gas. Diammonium phosphate is a commonly used source of nitrogen, and proprietary yeast foods are added to provide the yeast a variety of micro nutrients. Adding extra yeast nutrients is a simple and inexpensive way of avoiding problems with stinking fermentations. Unfortunately, hydrogen sulfide problems are occasionally encountered even when the best winemaking techniques are used.


Removing Hydrogen Sulfide


Some home winemakers use the following procedure to remove hydrogen sulfide from wine. (1) About 50 milligrams per liter of sulfur dioxide is added to the wine when fermentation is complete. (2) The wine is then aerated by racking with a great deal of splashing and bubbling. This treatment converts the hydrogen sulfide back into elemental sulfur, and the sulfur settles to the bottom of the container. Sometimes stinky wine needs to be racked two or three times to remove the stench completely. (3) After a week or two, the wine should be racked or filtered to remove the elemental sulfur. The smell may reappear unless the sulfur is carefully removed. However, aeration can convert hydrogen sulfide into disulfides, so this procedure must be used carefully.


Commercial wineries and some advanced home winemakers use copper to remove hydrogen sulfide from their wines. A 1 percent solution of copper sulfate is commonly used. When 150 milliliters of 1 percent copper sulphate pentahydrate solution is added to 1000 gallons of wine, 0.1 milligrams per liter of copper is produced in the wine. The copper converts the hydrogen sulfide into copper sulfide. Copper sulfide is not soluble in wine, so it settles to the bottom of the tank. A few days later, the winemaker racks or filters the wine off the copper sulfide residue.


Copper is a heavy metal, and only very small quantities can be added to wine safely. Additions often range from 0.05 to 0.2 milligrams of copper per liter of wine (mg/l), and home winemakers should never add more than 0.5 mg/l. Bench testing and careful measurements are required when copper is used. Little hydrogen sulfide and very little copper will remain in the wine when just the right amount of copper sulfate solution is used.