I used to make ginger beer, which is traditionally is cultured from a thing called a ginger beer plant; this is a jamjar full of nasty brown goop consisting of

I used to make ginger beer, which is traditionally is cultured from a thing called a ginger beer plant; this is a jamjar full of nasty brown goop consisting of a symbiotic mix of yeast and bacteria (and a lot of slowly decomposing ginger). What you're supposed to do is to leave a jamjar of sugary water out in the open for a few days so that it gets infected with whatever strain of wild yeast happen to be floating around your house. You keep feeding it for a month or so and the desired types of bacteria and yeast are supposed to outcompete the others and you end up with the right stuff to make ginger beer out of. Good ginger beer plants make good beer, and afficionados have been using the same plant for years, occasionally swapping cultures with other people to breed just the right culture to make really good beer. Me, I was squeamish about wild yeast in my 1900 British terrace mostly made out of damp rotting bricks, so I added a tiny amount of beer yeast to mine to get it started. Worked really well. I eventually lost the plant when I had to go on holiday, and so was unable to feed it. Instead I tried freezing it. The results when I thawed it were very weird --- I think the freezing process killed of all the yeast, but not the bacteria, or vice versa. It was certainly quite useless. Edit: Aha, instructions on how to make your own! https://delishably.com/beverages/How-to-Grow-Your-Own-Ginger-Beer-Plant https://delishably.com/beverages/How-to-Grow-Your-Own-Ginger...