Shrub dates back to colonial times. It was one of many ways that people could preserve fresh fruit in the days before refrigeration. To make a shrub, combine equal amounts of fruit and sugar. (It's a lot of sugar, but trust me.) We used blueberries, but you can use other fruit. Let this sit at room temperature for 2 days. Stir once or twice. The sugar won't entirely dissolve, but most of it will.
At this point, you can proceed with making your shrub. I'm only in the classroom once a week, so I popped it into the refrigerator until my next teaching session.
Strain the liquid from the fruit, pressing down to get as much syrup extracted as you can. (You don't need the fruit for this recipe, but don't throw it away. It is amazing on Greek yogurt.) Add an equal amount of apple cider vinegar to the syrup. You can sip it at this point. It is quite tart, but very tasty. If you have time, let it mellow in the fridge for a few days, weeks, or even months. It will become much less harsh. If it is still a bit too harsh for your taste, or if you want to guzzle rather than sip, add water. (Sparkling water is fun.)
Here's the 'recipe' in picture form. It really is ridiculously easy.
Enjoy! I'm going to be trying this with other fruits, starting with rhubarb. It's been awhile since I've fed my obsession.