Help! funny smell

You have come down with the dreaded Hydrogen Sulfide disease my friend! Hydrogen Sulfide forms during fermentation when there is an excess of Sulfur present on the grapes due to late spraying to prevent mildew, or there are certain critical nutrients missing or in short supply in the grapes. It has plagued winemakers since ancient times, and can be sometimes difficult to deal with even today. Leaving especially whites on the gross lees too long can cause this condition as well. I am still learning how to deal with this, I discovered I had this problem in a big way on my Chardonnay when I did the first racking. Phew! It was so strong my eyes watered.

First, the bad news: If you don't deal with this problem quickly, you might as well dump the wine down the sewer. What happens is that if the H2S remains dissolved in the wine, it will react with Alcohol to form Mercaptans, which in turn will form disulfides and polydisulfides, which are almost impossible to remove from the finished wine.

The good news is, if you catch the problem early you can probably save the wine. Hydrogen Sulfide is present as a gas in solution in the wine. By just aerating it, you will remove much of the gas, but you also will have to deal with the Mercaptans that are already forming in the wine. I Googled for information on this topic, and came up with these links, along with several other good links that concisely explain the problem, and how to deal with it:

nice try, but the poster said he is using pears and apples not grapes.

I once in a while get whiff of something "off" but usually the second whiff is ok, as are subsequent whiffs.

Sometimes you'll get odd smells that aren't the dreaded hydrogen sulfide, especially with fruits other than grapes. It appears that you're still in the primary, so try to whip some air into these batches. It will help the yeast take off, and remove some H2S that may be forming. Another thing to try is to add some yeast nutrient. If you want to see real foaming, you should add activator as well as nutrient.

| The possible causes of hydrogen sulfide contamination are:

• Too much sulfites, usually the result of grapes being dusted with too much sulfur during the growing season * Lack of proper nutrients (nitrogen, yeast hulls) during fermentation * Yeast combining with various forms of sulfur (some folks swear that Red Star Montrachet yeast is notorious for causing H2S, but we've never experienced this ourselves) * Bacterial contamination due to poor sanitation technique |

I'm not using grapes, and I doubt what I am using was sprayed. I washed eveything before hand. I'm thinking it's a lack of nitrogen or the yeast. I only used one packet of yeast and split it between the two batches. Of course it could still be a contamination problem.

I added 1 campden tablet, and 1 tsp of yeast nutrient (with other ingedients) the day before adding the yeast. I have no idea if my nutrient has DAP.

One site says "Do not add DAP at the beginning of fermentation, as it will overpower the yeast which has not yet had enough time to multiply to full activity." and another says "A common cause of stinking fermentations is a lack of nitrogen, and mild cases of H2S can often be cured by adding a small quantity of DAP to the fermentation."

I'll tried the aeration last night, and added some nutrient. Don't have a sulfide test kit, or any ascorbic acid or copper sulphate.

It smells better today, but still has a smell. Not so much a rotten egg, now it's more of a whiskey smell. I'm not sure what to think.

The red sumac color is now more orangish. Stu

Well, that should be sulfur powder, and not sulfites in that sentence. Which is what grapes are dusted with to prevent mold from growing. Probably not the case with your fruits, but you never know, they somehow gotta keep those fruits from molding as well. There are other sources of sulfur, for example, proteins in the must may be digested by the yeast to release sulfur, H2S is how yeast gets rid of excess sulfur in its diet.

Right here, its sounding less like H2S, and more like a general sort-of wierd solventy smell. That is typical, for example, my current batch of hard cider smells like that, with just a hint of rotten -- not rotten egg, not rotten fruit really, somewhere in between. I'm not worried about my cider, this will pass. My berry port didn't do this, but I figure just because the smell was masked by the fruit smell.

Yeah, that'll happen. Often, if the source of juice isn't grape, the color fades in even moderate light, or drops out in the lees, even if kept in the dark. Not a lot you can do about that.

Fermentation of peaches, apples, pears, and so on work with pretty much the same chemistry as grapes. Sulfur occurs to varying degrees in just about everything we eat. Fruit trees themselves have many of the same issues with powdery mold as grapes, in some cases even worse. They are dealt with the same way by an application of lime-sulfur spray just like grapes by the orchard men. It wouldn't be surprising to see H2S form in fruit wines as well.