Fine table salt is not necessary. What is known as common fine salt, or
even coarser grades, may be used. Caked or lumpy salt can not be equally
distributed. Salt to which anything has been added to prevent caking is
not recommended for pickling and brining. Alkaline impurities in the salt
are especially objectionable. Any noncaking salt which contains less
than 1 per cent of the carbonates or bicarbonates of sodium, calcium, or
magnesium may be used for this purpose.