We used to have a bunch of partially finished bottles of wine on hand. Life has changed. Cider is the drink of choice. Cider, when forgotten, quickly ferments. And when the fermented cider is exposed to the air, acetobactors take hold. We have allowed the last 1/3 of our cider jugs to take part in this fermentation two-step. The result is an intensely apple cider vinegar with a strong mother. It is an essential building block and canvas in our kitchen.