1) Crush or muddle the blueberries, then pour over the sugar and stir until the berries are coated and the sugar is evenly dispersed. I cover my fruit and let it sit out in a cool dark room overnight to ferment.
2) 24 hours later, pour the mixture through a sieve, straining the syrup from the fruit solids, and squeezing out as much liquid as possible.
3) You can use the leftover solids in pies or crumbles, or eat them with yogurt and granola.
4) All fruit is diﬀerent, and you'll get diﬀerent amounts of syrup from each batch, so I use a general rule of 1 part vinegar to 2 parts syrup.
5) Add your vinegar to the syrup, stir and let the shrub sit for a few hours before pouring into a sterilized Mason jar or bottle.
6) Refrigerate or store in a cellar for an additional week.
7) This concoction should keep nearly indeﬁnitely, if refrigerated, but discard if it changes color.
Yield 1½–2 cups syrup