Proportion of Honey to Water.
In the first place, we have to determine the proper proportion of honey to water.
Commercial Vinegar is required by law to contain a minimum of 3 per cent. acetic acid.[2]
Proof Vinegar contains 5·4 per cent., with a specific gravity of 1·006 to 1·019. For all ordinary purposes this is a convenient strength and first-class vinegars contain about this percentage.
Of course, the percentage of acetic acid is dependent on a satisfactory alcoholic fermentation and suitable conditions for the development of the acetic germ; but, supposing the conditions favourable, it is possible to obtain from an aqueous solution of 1 part honey to 8 of water, about 5 per cent. acetic acid. A suitable proportion will thus be 1 part honey to from 7 to 8 parts of water by weight.
Suitable Receptacles.
When made in small quantities almost any open vessel will serve as a receptacle for the liquor, always excepting glazed or metal ones, in which vinegar must never be allowed to stand. Owing to the solvent effects of the acid, the liquor is, in these cases, liable to be injuriously contaminated.
The vessel used should be covered with muslin or cream cloth, to protect from insects, etc.
A small cask is also a convenient receptacle, but this should not be filled more than three parts full and the bung hole must be left open, protected with gauze or other coarse material.[3]