SO2 additions to bind acetaldehyde?

[biertourist]

Yes, I realize that acetaldehyde in beer just means that you rushed fermentation or really didn't use enough healthy yeast, and I realize that making a "krausen bier" is probably the easiest/ best way to clean it up, BUT...

I started winemaking this fall and I ran across a tidbit of information that in winemaking the addition of SO2 binds with acetaldehyde and pulls it out of solution so it got me thinking: couldn't beer makers use the same technique with low levels of metabisulphite additions and then bubble CO2 through the beer with a stone to evolve the SO2 (which will slowly dissapate under aging?).

Obviously not a technique for a commercial brewery as it would take a long time, but as a theoretical science experiment / technique for a patient home brewer would this work?

Adam

 

[ajdelange]

The problem is that the SO2 forms an adduct with the acetaldehyde which, to my way of thinking, tastes worse than the acetaldehyde.

 

[biertourist]

The problem is that the SO2 forms an adduct with the acetaldehyde which, to my way of thinking, tastes worse than the acetaldehyde.

Oh... That's depressing...

Now I can't for the life of me understand why wine makers do it, then.


Adam

 

[botigol]

I don't know about it binding with acetaldehyde, but potassium/sodium metabisulfite is commonly used as a preservative in wine making.

 

[ajdelange]

Some brewers use metabite in beer to keep it in a reduced state (i.e. prevent oxidation in the package) rather than to reduce acetaldehyde. Wine and mead makers (and here I am going out on a limb as I don't really know much about wine) also dose their products with sulfites and I think it is for the same reason in part but also because it supreses the growth of wild yeast strains.

I should also point out that my experiences with acetaldehyde in beer were not with beers that were naturally loaded with the stuff but with beers that I had dosed with acetaldehyde to see if metabite would sucesfully reduce the flavor of it. The dosed beers didn't taste like acetaldehyde after metabite treatment but they certainly didn't taste very good either. Maybe at a lower level than the levels I used in my experiments would produce a more acceptable result.

 

[Yooper]

Some brewers use metabite in beer to keep it in a reduced state (i.e. prevent oxidation in the package) rather than to reduce acetaldehyde. Wine and mead makers (and here I am going out on a limb as I don't really know much about wine) also dose their products with sulfites and I think it is for the same reason in part but also because it supreses the growth of wild yeast strains.

Yes. As a winemaker, a general goal of sulfite levels is 50 ppm. It's used as an antioxidant during racking and storage, as well as a preservative. I've never used it in a wine where I perceived acetaldehyde so I can't say the effect it would have had. Acetaldehyde seems to be uncommon as an off flavor in wine.