2cupsfrozen or fresh chokeberriespicked over for stems and washed to remove grit if using fresh
3/4cupshighest quality red wine vinegarI like Beaufort
1/4of a fresh vanilla beanscraped, or a dash of extract (optional)
Bring all the ingredients to a simmer in a non-reactive sauce pot, about 2 qt size.
Mash the berries around with a potato masher or pulse very gently with a handblender to activate the deep color, but don't puree it completely.
Save the scrap for making berry scrap vinegar if you like. Simmer gently until the liquid is reduced by about 25%, being careful not to over-reduce the liquid or caramelize the berries in any way, which will destroy the flavor. When the syrup lightly coats the back of a spoon, turn the heat off.
Strain the liquid through a fine strainer, then reserve until needed. Remember the syrup will tighten up a bit as it cools too, so resist the urge to over reduce it--you can always cook it a bit more.
Transfer the syrup to jar or similar container. The syrup will keep near indefinitely in a tightly sealed container in the fridge and could also be water bath canned.