Get yourself a wide-mouthed ceramic or wooden container like this one.
Add wine. You can use any wine, but you probably don't want to use anything that's still good to drink. The real value of this recipe is putting an old stale bottle, or the 1/2 bottle you forgot in the fridge for a week to good use.
Add some good vinegar, the kind that's still alive. Most store bought vinegar will have been pasteurized, which makes it pretty useless in this situation. I recommend using Bragg's Apple Cider Vinegar, as it's generally the most commonly available unpasteurized vinegar. 25% vinegar to 75% wine is plenty to get you started, and you can get away with less vinegar.
Put a lid on your container. It should not be airtight. My container has a loose fitting lid that works great. It keeps the bugs out, but the vinegar can still breathe. You can use some thick cloth if your container doesn't have a proper lid.
Now put it somewhere for a month or so. You can give it a taste every now and then. When it tastes like vinegar, start cooking with it.
