Yeast and H2S

[Paisano]

Given the popularity of EdWort's Apfelwein, you are likely familiar with the typical H2S production that occurs around day three (or so) of fermentation. I've never encountered H2S production in the fermentation of a beer so this started me thinking about what was going on with wine yeast and apple juice.

I know that some bacteria produce H2S during anaerobic digestion. Does anyone know if something similar is occurring with yeast during apfelwein fermentation? Are yeasties capable of reducing sulfates for energy such as some bacteria do during anaerobic digestion?

Everyone reports excellent results with aging the apfelwein so there is apparently no deleterious effects from EdWort's method of fermentation. However, if the H2S production is about anaerobic digestion, I am wondering if a secondary oxygenation around day 2 of fermentation would offer improvements to the fermentation.

Any thoughts are appreciated!

 

[remilard]

It's because the must is nitrogen poor. Adding DAP will greatly reduce hydrogen sulfide production.

Also the Montrachet yeast is a notorious hydrogen sulfide producer.

 

[ajdelange]

Also the Montrachet yeast is a notorious hydrogen sulfide producer.

I think that's the key to it. Some strains produce lots of H2S. It is certainly a major component of "jungbuket". Whether it is from reduction of sulfate (and I think part of it is) or stems from sulfur containing amino acids or both I don't know. Any road, H2S is quite volatile and can be scrubbed by CO2.

Don't know anything about apfelwein in particular except that it is tasty.

 

[Paisano]

It's because the must is nitrogen poor. Adding DAP will greatly reduce hydrogen sulfide production.

Also the Montrachet yeast is a notorious hydrogen sulfide producer.

Is DAP diammonium phosphate? If so, I applied yeast nutrient at the recommended rate & the H2S off-gassing was still intense.

 

[Paisano]

I think that's the key to it. Some strains produce lots of H2S. It is certainly a major component of "jungbuket". Whether it is from reduction of sulfate (and I think part of it is) or stems from sulfur containing amino acids or both I don't know. Any road, H2S is quite volatile and can be scrubbed by CO2.

Don't know anything about apfelwein in particular except that it is tasty.

Hmmm... I use Cote des Blancs because it is what I had on hand but still experienced the H2S, even with yeast nutrient added.