What even is yeast? I am thinking mainly of the kind we use to make bread rise. Which I buy from the grocery store…
But, back in the day, where did people find yeast? I assume people cultivate it and grow it, much like sour dough, but someone had to find it originally, right?
And what does ir do in the wild? Especially since it is so easy to kill? (Can’t be too hot, can’t touch salt, can’t be too old…)
Note: this is purely to do with my curiosity. I have no interest in actually hunting wild yeast
In: Biology
It’s kind of just everywhere. On surfaces of things, and in the air.
A natural sourdough starter can start with just flour and water. Different varieties exist and even vary by region which is part of why there are varietals like San Francisco sourdough using the natural strains from the area to produce a different flavor profile.
It’s more sensitive for our uses like beer and bread because we want certain amounts to do what we need it to in specific situations. In the wild it doesn’t need to exist in a high concentration with specific temps because it’s just everywhere at a lower level.
Yeast is a fungus. Specifically a very simple, eukaryote, single-celled fungus that doesn’t grow hyphae (the hair that you see molds make).
Because it’s so simple it’s common absolutely everywhere, but if you wanted to isolate some of your own, you’d have most luck starting with some fruit that’s been left out too long and has started to ferment.
Edit: Important to point out that there’s no single “yeast”, there’s thousands upon thousands of different species. They would all “work” to ferment beer or rise dough, but some do this better than others and some are even pathogenic.
Yeasts are single-celled fungi. They are found absolutely everywhere in the environment. They particularly grow on plants. Some yeasts live on your body, and some inside your gut.
If you take a mix of flour and water and just let it sit, wild yeasts will start growing in it (this is how sourdough starters are made). They were on the wheat grains when they were milled into flour, and floating around in the air wherever you happen to live.
>And what does ir do in the wild?
It lives its life. It metabolizes food into energy, excretes waste products (like ethanol and carbon dioxide, which we humans find useful), and reproduces into more yeasts, usually by budding.
‘Yeast’ refers to a bunch of different species of single-celled fungus. It exists all around the place, and if you use different things as “starters” (for instance, fruit skins) you can cultivate some interesting sour dough flavours.
The yeast you buy from the store is one particular species – *Saccharomyces cerevisiae*, aka brewer’s yeast or baker’s yeast.
During earlier times before commercial yeast was available, people used sourdough starters. There is naturally occurring yeast in flour and if you mix flour and water and let it sit, it will ferment and “rise.”
Otherwise, breweries sold yeast as a by-product of making beer.
Yeast is a type of fungi which is very small. It does not create fruits like mushroom but spread spores directly from its main body. Yeast is found everywhere. There are spores floating around in the air you breathe. The yeast grow on surfaces of any organic matter as well as in water.
The most common place to find bread yeast is growing on the grains we use to make bread from. The yeast even survive most milling processes, only the bleaching kills the yeast. So the flour you buy does have some wild bread yeast already in it. But it is not enough to rise your bread like you want. This is why you add more yeast. But you can add water to the flour and give it some time, and feed it more flour and water regularly. The yeast will multiply a lot and become enough to make bread from. This is called a sourdough starter. Wild yeasts often produce acids as well, and often have lots of bacteria (the good kind of bacteria though) that also make acids. This is why the bread tends to taste sour if it is made this way.
[https://simple.wikipedia.org/wiki/Yeast](https://simple.wikipedia.org/wiki/Yeast) has simple answers. [https://en.wikipedia.org/wiki/Yeast](https://en.wikipedia.org/wiki/Yeast) has more detailed answers.
The easiest place (that I know of) to find yeast is on grapes. That hazy coating you see on grape skin is the yeast.
And I can attest, you can make bread with any kind of live yeast. Try making bread with brewer’s yeast used for making beer (the live yeast brewers use, not the “brewer’s yeast” dietary supplement you find in health food stores), and you’ll be so pleased with the outcome that you’ll never go back to baker’s yeast.
Back in the day you had your yeast starter. Basically you kept a small batch of bread dough to use as a starter when you wanted to make more bread. As others say there are lots of yeasts available so when you come across one that you particularly like, you keep a starter of that yeast. The packets in the store are your chance to get a good strain in a measured amount to use.
IIRC from my anthropology readings, the current theory for how we developed yeast cultures is that stored grain flours were inoculated by spores carried on the wind. Whether it was first used in leavening bread or in fermenting beer is still in debate.
I used to work with brewer’s yeast, Saccharomyces cerivisiae, and it’s a fun guy. I knew a guy who was getting a PhD in brewing science who replicated ancient Egyptian beer recipes. He discovered that his beer contained the antiobiotic tetracycline, and went on to hypothesize that that the presence of such antibiotics from the initial yeast colonies have made the beer safe to drink since the brewing process did not create sufficient alcohol to prevent bacterial growth.
To make bread you just need a shallow bowl full of water with a little flour, left somewhere dark and warm. After a day or two it will start bubbling. Now add the rest of the flour, knead, and let it rest for a few hours. Ready to go.
Only problem is, you have no idea what kind of yeast your using, or what other microbes are growing in the mix.
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