Homebrew Soda Extract in Kegs

[7seas]

I picked up a Homebrew soda extract today for my kid. I figured I could dump it in a keg, add some sugar, force carbonate and then she'd have something on tap next to daddy's brew. The instructions that came with it are all for natural carbonation (add 0.5-1 tsp dried yeast with 8 cups table sugar and store at 70F). The extract contains sodium benzoate, so I assume that it eventually kills off the yeast before all the sugar is fermented out, but I am not sure how much residual sugar would remain. Any ideas?

[bub]

almost all of the sugar will remain, don't change the recipe just force carb as described.
BUB

[Bugeater]

Left to finish out on its own, the yeast will pretty much eat all the sugar in spite of the preservatives. The tiny amount of benzoate is in there is to keep the extract itself from spoiling while on the shelf. It won't be enough to bother the yeast.

The recipe depends on you refrigerating the soda as soon as it is carbonated so that the fermentation nearly stops. It also assumes you will drink it all before it progresses too far. The amount of sugar consumed for carbonation is only a small portion of what you added.

Since you want to keg this anyway, lose the yeast and just force carbonate like you would beer. That way if you have to stick it somewhere at room temperature for a while, you won't end up with extremely carbonated soda that isn't at all sweet. You may want to cut back the sugar by the amount you would normally use for naturally carbonating the same volume of beer.

Wayne
Bugeater Brewing Company

[7seas]

Bub and Bugeater, thanks for the advise. I think I'll try Bugeater's suggestion first (ie. reducing sugar by what I would normally add to bottle condition a beer). If it isn't sweet enough I can always add more.

Since the benzoate won't act as a preservative, should I also add some potassium sulfite?