Slurry!

I'm intrigued by this magical gurry that's left over from my brew. So intrigued that I collected it from the primary and secondary and put it in a bowl in my fridge, where it awaits its uncertain future. So here goes;

How long is it good for?
Can I use it to bake bread? Have any of you done this?
Is this what brewers in pre-yeast discovery days used to get their next batch bubbling?

Matthew_Eldon_Verge said:

How long is it good for?

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You can keep a jar of slurry in your fridge for about a month if you followed good sanitation procedures. If you sterilize and freeze, you can get much longer. It's a pretty involved process so you should look for the sticky that tells you how.

Matthew_Eldon_Verge said:

Can I use it to bake bread? Have any of you done this?

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Bread? I guess you could but I haven't done it. Bread yeast is cheap and not near clean enough for brewing.

Matthew_Eldon_Verge said:

Is this what brewers in pre-yeast discovery days used to get their next batch bubbling?

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<insert age related insult aimed towards your favorite homebrewer/gnome.>

The slurry is a mixture of live yeast cells, dead yeast cells, proteins from the boil ("hot-break" and "cold-break"), and probably chunks of hops (definitely if you used pellet hops), maybe some hop seeds.

Matthew_Eldon_Verge said:

How long is it good for?

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If you keep it from getting contaminated it can be good for anywhere from a day or two up to about 6 months, depending on the method by which you preserve it. Yours is probably contaminated from sitting in an open bowl in your germy fridge. Check out the yeast washing sticky (under general techniques on this forum) for good instructions on what to do to save it for a long period of time. Another simpler method is presented by Charlie Papazian in his book, "The Complete Joy of Home Brewing," this method is probably not good to keep it for as long. The final easiest method is to brew a new batch of beer the same day you bottle or keg a previous batch that used the same type of yeast, and just pitch the new beer directly into the fermenter on the old yeast cake without cleaning or anything. Works awesome but you gotta brew that day.

Matthew_Eldon_Verge said:

Can I use it to bake bread? Have any of you done this?

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I haven't tried baking bread with it. Maybe someone else has. You should try it and tell us what happens!

Matthew_Eldon_Verge said:

Is this what brewers in pre-yeast discovery days used to get their next batch bubbling?

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It is yeast. If you treat it carefully, it can be used to ferment another batch.

Thanks, guys. I should have viewed the sticky first! I am going to try baking bread with it tomorrow.

What I meant by my last question is that, to my understanding, brewers before the 19th century didn't know what yeast was. Did they use the slurry, then, knowing it would cause fermentation but not understanding why, or did they rely on air-born or localized yeast strains entirely?

They often used the 'magic brewing paddle'. This was a wooden paddle that was unknowingly infused with yeast cells. They knew that when they used the magic paddle the beer was better. I can't say whether or not they used the slurry but I would imagine so.