Stabilizing a sour beer, like wine?

[wickerman]

I want to add some fruit juice & maybe lactose to a sour beer that I will be kegging. It is from a solera type barrel that is at least a year old (since last addition). I probably won't drink it fast enough to rely solely on refrigeration to keep fermentation at bay. I've read that people sometimes use wine additives like sulfites and sorbates to help stabilize in this type of application, but can't really find any info on what exactly to use, or how much. I have never made much wine, and didn't ever put any of that stuff in wine I've made. I do believe I have potassium metabisulfite (or something like that) that I used in a holding solution for a barrel. Also have campden tablet if they'll do anything.
Any recommendations in what to use & how much? Any suggestions are greatly appreciated.

 

[RPh_Guy]

To stabilize you need potassium sorbate, which prevents yeast growth, and potassium metabisulfite, which inhibits bacteria. Minimize the amount of yeast transferred into the keg.

Potassium sorbate: 1.53 grams per US gallon (300ppm sorbic acid)

Potassium metabisulfite: 0.14 grams per US gallon (targetting 0.8 ppm molecular SO2 [21ppm free SO2], assuming 3.2 pH)

These recommendations are for wine. I don't see any reason why they wouldn't apply directly to sour beer as well.

cheers

 

[ten80]

These recommendations are for wine. I don't see any reason why they wouldn't apply directly to sour beer as well.
cheers

wine dosing will probably be low for beer because sulfites can be bound (and inactivated) by organic matter, and there is a lot more organic matter in beer (proteins, polysaccharides, etc) than in a finished wine. As a result, the concentration of free SO2 will probably be lower than expected. That said, I have not yet tested this in my beers.

If this were my beer, I would rack it off the yeast and add sulfites and sorbates at the doses RPh Guy shared above. Then rack again to a keg after all yeast has settled and add a second dose, plus your fruit juice and lactose. I generally rack my ciders three times, dosing each time, and they have been very stable. Of course, the risk of oxidation is very low with cider, but not with beers, so transferring with CO2 pressure should be used if possible.

Whatever you do, you MUST add potassium or sodium metabisulfite if you add potassium sorbate, otherwise the sorbate may be metabolized by certain bacteria into geraniol, which tastes like geraniums. This happens fairly often in wines.

 

[RPh_Guy]

Based on the experiences of LODO Brewers using sulfite, even small amounts are enough to affect the yeast. Therefore I think sulfite binding in beer is relatively low.

I definitely wouldn't add more than 300ppm sorbic acid. It's already well above tasting threshold at that level, and it's the legal limit in the US.

 

[ten80]

It's more a factor S.cerevisiae used for beer brewing having a very low tolerance for SO2, whereas wine yeast (S.cerevisiae var. and S.bayanus) and Brettanomyces have a documented high tolerance that was developed as a competitive mechanism. Since the OP asked about sour beer, I'm assuming that he needs wine-like levels of free SO2.