What’s that smell?
That terrible rotten egg smell that can occur in wine is the result of hydrogen sulfide forming at the end of
the fermentation. If caught early enough it can be treated. Better yet, you can avoid it.
Causes and Preventions:
• Cause: Too many sulfites present.
• Prevention: Carefully add the correct amount of sulfites to the wine.
• Cause: Lack of proper nutrients such as nitrogen.
• Prevention: Add nutrients during fermentation.
• Cause:The combination of some yeasts with sulfites.
• Prevention: Use yeast properly and carefully. Make sure it has not expired and rehydrate prior to
• adding it to the must. This ensures the yeast is still active.
• Cause: Bacterial contamination.
• Prevention: Sterilize all equipment and materials that come into contact with the wine.
Treating the Problem
If hydrogen sulfide has formed in your wine, it is not necessarily too late. But if left too long it will react with
other carbon compounds in the wine and become too difficult to remedy. So act fast.
Here are some procedures to treat and condition:
• Measure the sulfites in your wine. Treat to 50 ppm (parts per million).
• Rack your wine. Be sure to splash it around quite a bit in order to get oxygen into the wine.
• Aeration, the introduction of oxygen, helps to counteract hydrogen sulfide.
• Put the airlock on and leave the wine over night.
• If the problem is still not fixed pour the wine over a piece of copper into another receiving vessel.
• The chemical reaction should neutralize the odour.
• If the wine is not completely cured, add an egg white or gelatin as per the suppliers instructions.
• As a last resort add copper sulfate. But be very careful because in large quantities it can be
• poisonous! DO NOT EXCEED 0.5 PPM OF COPPER SULFATE (0.1% solution added at 0.5 mL per
• gallon will give you 0.3 ppm of copper sulfate).
• Add Bentonite or Sparkolloid fining agent to remove the copper sulfate.
• If the condition has been treated successfully, filter the wine to bring it to a polished finish.
It is important to take care at all stages of wine making. The care that you take at the beginning will save
you a lot grief at the end.