This forum seems to focus on brewing beers and similar, but there are oh-so-many other ways that fermentation can make delicious, yummy foods and drinks.
I normally have three tanks of beer fermenting, and often a tank of sugar wash for a still. This tends to get made into large amounts of limoncello, or used in making other fruit liqueurs.
I regularly make yogurt - mixing up powdered milk, heating then cooling it, and adding a teaspoon or so of Easiyo makes vast quantities of nice tart yogurt when left on a heating pad for a couple of days. Way cheaper than buying it.
Water kefir - I've just started experimenting with this, but it is very refreshing, and popular with my wife. Again, a great way to use whatever fruit is lying around.
Sauerkraut - letting this go for a few weeks makes it oh-so tart and yummy. I'm going to try lacto pickling of other veges shortly as well.
Kvass - I originally got intrigued by this from Boris, a Russian YouTuber recommended by my kids. Keeping 20 litres of this warm with a temperature controller is very easy in the still.
Kombucha - again, a favourite of my wife.
My wife, being Japanese, also makes amazing miso, as well as natto (utterly gross).
Anybody else got any micro-organism-related projects using going on?