The scent of egg.... is this OK?

[lanzafame]

Hello,

My current project of rhubarb wine fermented very vigorously for about days, then got very quiet, and after another couple of days has developed an eggy/sulphur smell.

I've heard that in brewing beer, this is ok, but what about with wines? has anyone else experienced this, and is it a bad sign?

thanks

Tom

 

[Rocky]

Tom, it is not a good thing and normally indicates an issue with the yeast.

 

[robie]

Rocky is right. At least in most cases it is fixable. It has developed H2S, which is a rotten egg smell.

Take a three very shinny, bright and clean pennies and put them in a wine glass. Fill the glass 1/3 full with your wine. Swirl the wine for about 3 or 4 minutes. Smell the wine and determine if the smell has lessened. The longer you swirl it, the better it should smell.

Let us know if this works.

 

[lanzafame]

Right, i'll try that. sounds intriguing, if not slightly worrying.

so does this test with the pennies determine whether it's H2S?

what are the implications for the rest of the batch if the pennies lessen the smell of 1 glass of wine?

thanks for your comments guys.

tom

 

[Rocky]

If it is H2S, the S will combine with the Cu and O and form CuSO4 and the H will go to atmosphere. Some of us have solved the problem by hanging copper wire (like what is found in a Romex cable) in the carboy to take up the S.

 

[robie]

Yes, for most home wine makers, the solution is copper. That's why you test with pennies, as they are copper coated and work rather quickly on a tiny sample.

Another thing to do is buy a copper mesh pot scrubber pad from most any grocery store. Sanitize it really well; tie a piece of nylon fishing line onto it and drop it down into your carboy with the other end of the line hanging outside the carboy. I have also used a new, clean, sanitized copper tube to stir the wine and to rack the wine through it.

The very best solution for home wine makers is to have some Reduless on hand. It is a powder made especially for H2S and really takes care of the H2S problem, but it might be too late for that, as it has to be ordered from someplace like morewine and it could take a week to arrive. I don't think you want the problem to stay around that long as it could turn into something much worse and the wine would have to be discarded.

 

[saramc]

This is what http://www.grapestompers.com/hydrogen_sulfide.aspx (good explanation: causes-prevention-treatment,etc) recommends you do:

• First, measure the amount of sulfites in your wine using a test kit
• If deficient, treat wine to 50 PPM sulfites
• Rack and splash - rack your wine two or three times, being sure to splash it around a lot as the wine goes from vessel to vessel. The aeration (introduction of oxygen) will help counteract the H2S.
• Put the airlock back on and wait a couple of hours or overnight. If it still smells like rotten eggs, keep going...
• Get a piece of copper (i.e. copper flashing) from a home supply store.
• Pour the wine over the copper so that it runs over the surface of the metal into a receiving vessel.
• Fine or filter the wine.
• By now, the sulfur smell should at least be greatly diminished. If you can still detect a smell (we've heard that humans can detect H2S in quantities as low as 2 parts per billion), you might try to use an egg white or a gelatin fining agent and fine your wine. Add normal amounts recommended by the manufacturer.
• Filter wine through a tight filter.
• When all else fails you can use copper sulfate on your wine. A 0.1% solution added at about 0.5 ml per gallon, will give you about 0.3 PPM copper sulfate in your wine. BE CAREFUL. Remember, this stuff is poisonous. DO NOT EXCEED 0.5 PPM of copper.
• Fine your wine with a bentonite or Sparkolloid fining agent. This will remove all the copper sulfate.
• Filter wine if necessary to remove fining agent.

Don't forget that sometimes it can be something as simple as the yeast you used with the batch...but you still have to know how to fix the problem.

 

[Lurker]

Try stirring with copper electrical wire. No problem getting it out.

 

[captainl]

Aren't pennies made of zinc now....use one from pre 1982 if you do.

 

[ckassotis]

The alloy remained 95 percent copper and 5 percent zinc until 1982, when the composition was changed to 97.5 percent zinc and 2.5 percent copper (copper-plated zinc). Cents of both compositions appeared in that year.

Mostly zinc, but the part exposed to the wine would be copper.

 

[deboard]

I thought that the sulfur smell can indicate a nutrient deficiency in the must? If it's still fermenting, adding more yeast nutrient can help. If it's already in secondary or farther, the copper seems like the best choice.

I've only encountered this once, on the 3rd or 4th day of fermentation. SG was still decently high, so I added nutrient and it went away.

 

[ckassotis]

Yeah absolutely. You aren't supposed to add any nutrients after the first part of primary fermentation though. Someone reminded me the other day of about 1/3 of the S.G. as the marker. So when it has dropped below 2/3 S.G., you need to use other methods besides the nutrients.

 

[deboard]

Never heard of that rule, do you know why you're not supposed to add nutrient after 2/3 is done? Not disagreeing, just curious.

 

[saramc]

Never heard of that rule, do you know why you're not supposed to add nutrient after 2/3 is done? Not disagreeing, just curious.

Scott Lab says "Yeast metabolize nutrients at different times throughout fermentation. Dosing nutrients at the most optimal moments can enhance yeast performance. As fermentation progresses and the ethanol level rises, yeast becomes less and less able to assimilate nutrients. For this reason, each nutrient has been created for specific addition times. For example, GoFerm has been designed to add during rehydration. Other nutrients like Fermaid K are added at one-third sugar depletion and never into the rehydration water."
Addition of the right nutrient at the right time frame also has a lot to do with nitrogen, you may have read people talking about YAN, YANC, etc. Use of nutrients also relate to the yeast you choose as some tend to require that extra UUMPH! or they start kicking out the dreaded rotten egg smell.
Scott Labs also advises to avoid using products containing ammonia salts, such as DAP, during yeast rehydration - they are toxic to the yeast at high levels (so GoFerm is a great rehydration yeast nutrient http://www.scottlab.com/product-102.aspx )
Here is a good overview of FermaidK--a complete yeast nutrient http://www.scottlab.com/product-104.aspx which is added either at 1/3 sugar depletion in two doses or at the end of lag phase + at 1/3 sugar depletion.

Hope that helps...

 

[deboard]

Yes, that helps a lot. Never knew nutrient could be that complex.