by blond.chap » Tue Oct 08, 2013 3:34 pm
Ah, yes if it's already fermented out there's no need to adjust pH, only really important for getting a good fermentation going.
Soda ash is sodium carbonate, it's the main thing used for adjusting pH in winemaking, also used for adjusting pH in swimming pools.
Soda ash and citric aren't then only things used to adjust pH, you can use any alkaline or acidic substance. However you're probably best off sticking with something food safe and not too corrosive (probably wouldn't use sulfuric acid, hydrochloric acid, caustic soda etc.).
The common additives to reduce pH (make more acidic) are tartaric acid, citric acid and malic acid. Common additives to increase pH are soda ash and caustic soda, as I said though, I'd steer clear of caustic, easy to burn yourself.
There's subtle differences to changing pH when making beer or wine, but for distilling 3-4 should keep your yeast happy, just as long as around that range.