Fast forward to now, and the beer had spent its required time in the plastic keg, and it was time to move it to bottles for carbonation. That went well enough, but after filling the bottles, I was left with some liquid in the bottom of the keg.
First, I drained off the mostly-clear liquid. It was a bit cloudy from the sediment at the bottom of the container, but I figured it would be fine for cooking. After all, it's just flat beer, right?
At the bottom of the container was a tan-colored substance. I added some water to the keg and swirled and sloshed it around to loosen it up to dump it out. And then the light bulb lit. This stuff is all filled with yeast, and that stuff on the bottom - well, there might be some dead yeast there, but it was probably mostly dormant.
Now, what can I possibly do with that?
Yeah, right. I decided to try to make some bread with it. After all, the first yeasts used for bread-making were beer yeasts. We've moved on, but what the heck. It seemed like a good challenge.
I took a cup of the cloudy stuff and added some sugar - unmeasured, but probably about a teaspoon or so. And I let it sit. And sit. And sit. After a while I saw a little froth.
At that point, I was thinking that maybe the yeast wasn't all that active. But the little bubbles gave me encouragement, so I added a cup of flour, and as soon as it hit the liquid, it frothed up like mad. Well, that's interesting. I mixed the flour in and let it sit for a while, and it wasn't just weird frothiness, it was rising.
Well, okay, then. I added another 1 1/2 cups of flour, 1 teaspoon salt, and 1 tablespoon olive oil. I kneaded it for a while, but then figured that it would have to spend the night in the refrigerator - it was getting too late to be baking bread. So I kneaded for a short while, then made a ball of the dough, drizzled it with olive oil, and popped it into a zip-top bag. I put the bag in the refrigerator.
The next day, I pulled it out of the fridge and left it sit on the counter for a couple hours to warm up. I preheated the oven to 350 degrees, sprinkled some cornmeal on a baking sheet, and formed the dough into a log and plopped it on the baking sheet to rise.
After about 90 minutes, it was barely doubled in size, but I wasn't sure how it would behave in the oven, so I slashed it and baked it.
The oven spring wasn't huge, but that's okay. The bread was nice, and this was just a first experiment. I've got some more of the mixture in the refrigerator. I added some flour to it, like I would for a sourdough starter. I'll be keeping that for future fun. This should be interesting.
I know what I've presented isn't much of a recipe, but if you make your own beer and you bake bread, use it as inspiration - there's live yeast left in the stuff you don't bottle. You might as well use it.
And here's a little holiday bonus for you. If you order from Mr. Beer through the end of December, you can get free shipping with the coupon code "cookistry"!
This has been submitted to Yeastspotting.