H2S during MLF?

[RonObvious]

Thanks, we haven't tried AMH yet, but we have tried BM4x4. RC212 seemed to do a better job of softening hybrid grapes' acidity while maintaining the bold fruit aromas I like so much. Maybe you're right - just go generous on the nutrients and check frequently. I think I may bite the bullet and try Avante too - the promise of no H2S AND also munching down some of the malic acid sounds pretty appealing.

 

[RPh_guy]

For those looking to learn more about H2S, I've covered this off flavor extensively on my wiki:
Hydrogen sulfide - Modern Brewhouse wiki

While bacteria can certainly produce H2S, I didn't come across any research specifically about MLF.

Cheers

 

[JohnT]

You need to address H2S as soon as you can. H2S can (over time) bond into other nasty compounds (eg mercaptans) that are harder to address.

I recommend that you look into a product called redueless. It is not toxic like copper sulfsate and gives more control over copper dosage then simply exposing you wine to copper metal.

I use RC212 fr most of my red wines. I do 3 nutrient feedings during AF and H2S is a very rare occurrence.

 

[RPh_guy]

You need to address H2S as soon as you can. H2S can (over time) bond into other nasty compounds (eg mercaptans) that are harder to address.

This has only been theorized, never proven.

I recommend that you look into a product called redueless. It is not toxic like copper sulfsate and gives more control over copper dosage then simply exposing you wine to copper metal.

Check out the article I linked in the previous post.

Arguably copper sulfate gives greater control over VSC removal than Reduless because you can more easily do a bench trial. It's not toxic when used appropriately. Reduless allegedly has fringe benefits though, if you want to solely rely on their marketing (which is dubious).

 

[JohnT]

This has only been theorized, never proven.


Check out the article I linked in the previous post.

Arguably copper sulfate gives greater control over VSC removal than Reduless because you can more easily do a bench trial. It's not toxic when used appropriately. Reduless allegedly has fringe benefits though, if you want to solely rely on their marketing (which is dubious).

It is a darn good theory. To get rid of mercaptans I use ascorbic acid / copper treatment. From my understanding, the ascorbic acid breaks the bonds, so that the copper can then address the sulfur issues. I am no chemist, and I am sure that you can argue the science, but this system works like a charm.

When dealing with H2S issues, you need to realize just how little of the stuff there is in wine. Just 1 ppm of H2S could knock you backwards. We are dealing with a very small scale. This is why I like redueless. It is more gentle and less toxic (I believe) delivery system then copper sulfate.

 

[RPh_guy]

Your understanding is correct with regard to mercaptans and disulfides. However it's still unclear whether H2S contributes to forming these compounds.

Copper sulfate is not any more toxic than Reduless if the product is used appropriately. However, if the powder form is more convenient, then great (and Kupzit is also a good option for a powder). The liquid form does have a significant advantage though: being able to more accurately dose it via a bench trial.