Miso is a staple of Japanese cooking. Nowadays you buy it ready-made in supermarkets or miso-shops, but up until fairly recently it was not uncommon for people to make their own. It's really quite simple: cooked soy beans, rice or barley is mixed and fermented with "koji" until it turns into a brown, intensely flavourful paste.
I stumbled on a miso-making kit recently, so we're having a go at it. You could easily get the ingredients for yourself of course, but it's very convenient to get the right amount of everything and a set of instructions.
Now we wait. The main risk is getting mold on the surface (that's what the kitchen wrap and the weight is all about). Check every month or so, and if green or black mold appears just scoop it up, then sprinkle salt over that bit to stop it from reappearing. Some recipes call for a layer of salt on top, but that makes the miso rather salty.
In May, when temperatures rise, the process will start to speed up, and by October or November the color should begin to change. Once it's done, put it in airtight containers and keep it in the fridge. That's cold enough to stop the process, and the miso should keep for many months. We'll see if we succeed.