You'll stare at a slimy beige disc floating in sweet tea and genuinely wonder if you've ruined it, and the first few batches will be either flat or aggressively vinegary.

Once you dial in the timing and start a second fermentation, though, you get a fizzy, tangy drink you tuned to your own taste.

The catch is the rhythm: it ties you to a roughly weekly cycle, and a neglected jar will overshoot into sour fast.