2,479. Beer Vinegar; Brine

Maachalos Assuros 17:25

The reason non-Jewish beer vinegar is prohibited is because they put the wine dregs in it; vinegar from a storeroom (before the dregs are put in) is permitted.

Maachalos Assuros 17:26

Non-Jewish fish brine is prohibited in places where the practice is to add wine; if the wine costs more than the brine, then it’s permitted. This is the case whenever we’re concerned that non-Jews might mix something prohibited into something permitted. Someone won’t mix something expensive into something cheap because he’ll lose money, but he will mix something cheap into something expensive and make a profit.