1636. How To Clarify Isinglass

Take two ounces of the clearest isinglass for a mould of jelly, put it in a stewpan with water enough to cover it, set it by a stove with a spoon in it to stir it and skim it when any scum rises; let it boil very gently and well reduce, be careful not to reduce too much as it will burn and spoil your jelly, when you think it is reduced enough pass it through a sieve ready for use.

1637. How To Clarify Isinglass

Take an ounce and a half of the best isinglass, cut it into pieces and wash them in warm water several times, put the isinglass into a stewpan with five glasses of filtered water, set it on the fire, and as soon as it boils set it at the side of the stove so as to keep up the boiling; take off the scum as soon as it rises, and when the whole is reduced to three quarters strain it through a cloth into a basin for use.