Concord Grape Vinegar
By Lou Bank
I never would have thought of this, let alone figured it out, without the support of Sandor Ellix Katz's remarkable book, Wild Fermentation. If this is your thing, go here.
Remove two bunches of Leaning Shed concord grapes from the stems. Put them into a glass container that is at least as wide at the top as it is at the bottom (a cylinder—many vases are great for this).
Mix 4 cups (1 quart) room-temperature Leaning Shed spring water (or, you know, any spring water) with ¼ cup granulated sugar. (I like Billington's demerara sugar. Try different sugars, and you'll find they create different flavor profiles. But be aware that different types of sugar—like honey or agave nectar—ferment at different rates than cane sugar.) Stir until sugar is dissolved. Once dissolved, pour sugar water over the grapes. Cover the glass container with cheesecloth, using a rubber band to hold the cloth down. Put the glass container in a warm, dry location.
Once or twice a day, use a metal spoon to push the fruit below the water level. It will immediately bob back up, but you'll have moistened it, thus preventing mold from growing. After a day or two, you'll see bubbles forming. This is fermentation! Your vinegar is alive! Continue this process each day for seven days.
Remove the grapes by pouring the mixture through a fine sieve, retaining the liquid. Put the liquid into the same kind of wide-mouth container (if using the same container, give it a quick cleaning). Cover with cheesecloth, again using rubber band to hold down. Put it into that warm, dry place, and leave for two weeks. Strain once more (I usually put it through a coffee filter) and it's ready to serve.
Be aware: the pH levels of homemade vinegar are nowhere near that of mafuactured vinegar. So when a recipe calls for "vinegar," it assumes it'll be strong; you'lll need to add more of your homemade vinegar. And if you're bottling chili peppers or the like, this vinegar won't bring enough acid to the party to prevent bacterial growth.