Remove the grapes from the stems, wash them in a colander, then press
the pulp from the skins. Boil the pulp for a few minutes, until it will
easily separate from the seeds. Rub it through a sieve, add the skins,
and weigh or measure the mixture. Add an equal quantity of sugar, heat
it over a moderate fire until it is simmering, stirring it frequently.
Do not let it boil hard or the skins will be toughened. Set it in a
cooker for three hours or more. Put it into sterilized glasses or jars,
cover it with a towel until it is cold, and seal it as directed for
apple jelly on page 169.