- Suppose I did not adequately rinse the sodium percarbonate solution from my fermenter/bottles. Could this a) make somebody ill or b) affect the flavour of the beer?
- When I left sodium percarbonate solution in my demijohn to soak for 20 minutes, a residue was left at the bottom (sodium carbonate?) which did not rinse out with water. In the end I resorted to white vinegar to get rid of it. a) Does his sediment pose any threat to health/flavour and b) how can I avoid this nuisance in future?
- For bonus points, what if I'd used sodium/potassium metabisulfite?
Sodium percarbonate forms hydrogen peroxide which eventually breaks down into oxygen and water.
1a. I think you'd have to leave a lot in. Apparently hydrogen peroxide is used as an antiseptic mouthwash so it must be acceptable to ingest a small amount.
1b. I've read that not rinsing "oxy" type cleaners means oxygen can be created in beer, which can result in oxidisation and associated off flavours.
Try to make sure the powder is dissolved as much as possible before putting it in the demijohn. Otherwise I just rinse a bit more vigorously, and live with it if I can't remove completely. I don't think it's contributed any off flavours.
Presumably since this is used in preparation of wine and cider it is not considered to be harmful to health. However in these contexts it's used to kill wild yeast, I think it's not generally considered to be an effective antibacterial agent for the purposes of sterilisation.
1 - It will leave extra salt in your beer and raise the pH, which won't make anyone sick at reasonable levels.
2 - Lower the pH of the solution, like you did with vinegar, so that carbonate doesn't precipitate.
3 - Metabisulfate would leave sulfur in solution too, which would impact the flavor more than carbonate.