From 1912:
Wash the grapes, Concord, thoroughly in cold water, weigh, allowing three-fourths of a quart of water to every five pounds of grapes, boil until pulp and skin are thoroughly separated and boiled down. Make a bag of doubled cheesecloth large enough to hold all the juice that would fill a small bread pan, tie the top tight with a stout cord, and hang up on a strong nail or hook so that it can drip into the pan. It will take about fourteen hours to drip through. When all is strained through, add one pound of sugar and boil again two minutes. Get any good sized bottles with tight fitting corks, heat them gradually from warm to hot water, and fill with juice. Then cork, melt sufficient paraffin wax, and dip the cork and neck of the bottle in this wax, which will keep them airtight for any length of time. If you buy grapes when cheap, one bottle full of pure juice will cost you about 6 cents.