This summer I read Entangled Life which is a lovely book about all the cool things fungi can do. I very much recommend it in general, but the part that’s relevant here is the bit talking about yeasts and fermentation. Turns out that for all the snobbery that’s out there about brewing alcoholic drinks like wines and ales, the basics are actually very simple and not hard to do at home at all.
Here’s the tl;dr: If there is yeast in a liquid containing sugar, it will consume the sugar and make alcohol and CO2 out of it. That’s it, now you have a beer/wine/cider/hooch.
An experiment
After reading that I just wanted to see the magic for myself, as I could not quite imagine that leaving a bunch of fruit floating around at room temperature would result in anything other than a disgusting mess. So I ransacked my pantry and came up with some premium ingredients:
- a dusty packet of bread yeast
- half a pound of cherries
- A half empty jar of mostly crystalized honey
I googled a mead recipe to find out that a 2:1 water:honey ratio is pretty normal, so I dumped the honey out into a pot and rinsed what was left out with some water that then became part of the brew too. I pitted and smashed up the cherries. I simmered the whole thing for a little while to make sure everything currently living in it was dead, threw it into a small vase (figured it would be hell to get the cherries in and out of a bottle neck), and after it cooled added the bread yeast. Covered it with some plastic wrap and waited.
Sure enough the next morning the plastic was bulging up from the CO2, and the cherries looked absolutely disgusting with the color leached out of them and the yeasty foam sitting on top. Not exactly appetizing but at least it seemed to be working, so trust the process and wait. After a week or so it had stopped bubbling so I fished the cherries out with a small sieve and poured the remaining liquid minus the sediment at the bottom into an old screw-cap wine bottle.
At this point I’d done a bit of online research on brewing and heard that if you just let it sit it will clear up on its own so I put it in the fridge for a week. End result: a pretty clear red-pink liquid that tastes a little but not overly sweet, more of honey than cherries. Perfectly drinkable stuff.
Down the Rabbit hole
Seeing what some random ingredients in a vase covered in plastic wrap could do, I got pretty hooked on finding out what brewing ‘for real’ is like.
Now there’s lots of tutorials out there and I won’t bore you with every single thing I learned but the short version is that I’m now the owner of several 5 liter carboys and a small crate of brewing doodads, subscribed to several new youtube channels, and proudly drinking my own mango-mint, orange-chocolate, and peach-tea hooch.
For anyone with a large bowl and some bread yeast, here are some pointers if you want to give it a go:
Quick-start guide
Types of yeast
Pretty much all yeast that you can buy is the same species (Saccharomyces cerevisiae). Bread yeast, ale yeast, and wine yeast and their subtypes are all just different strains bred for different flavor profiles and environmental tolerances, like their favorite temperature and maximum amount of alcohol. There are also yeasts living in nature (wild yeast), often on fruit, which you can try to employ to make alcohol for you. But with those you never know what you’re going to get.
Carbonation
As mentioned, yeast produces CO2 which at room temperature is a gas. This means that if you put your still-fermenting brew into a closed container (bottle with a cap, bucket with a lid etc) pressure will build and potentially explode your vessel. You can buy a cheap airlock but for first time experiments solutions like putting a lid/cap on but leaving it loose so the gas can escape is fine too.
Cleanliness
While you want the yeast to have a good time in your brew, other microorganisms are not so welcome. There are commercial disinfectants for brewing equipment on the market, but rinsing stuff out with really hot water is most likely good enough. Humanity was brewing well before clean tap water and soap were invented. Just be sane about it: if you see hairy lumps growing on the surface or it smells of rotten eggs, don’t drink it. You’ll see some yeast foam that looks kinda gross but that’s supposed to be there 🙂
Alcohol content
Yeast eat sugar and produce alcohol until either they run out of sugar or they are swimming in so much alcohol that they can’t deal with it any longer. So the amount of alcohol in your brew depends on how much you feed them vs. how much they can handle. There are handy conversion tools that take sugar/liter and tell you the potential amount of alcohol that will make. Commercial brewing yeasts will list the alcohol tolerance in their specifications. From a pack of bread yeast you can expect maybe ~8%.
Methanol
You’ll make some as a natural byproduct, but it will be very small amounts that won’t hurt anyone. Don’t worry about methanol unless you want to get into distillation.
That’s it! Go forth and ferment!