Make your own yeast

[grower]

Prepper Baking 101: Making Your Own Yeast

Mar 28th, 2011 | By Samara |
Knowing how to replace the staples in the kitchen in some other way than a trip to the store is an important prepper skill. One of those things is bread. The first step is taking the time to learn to bake, which unfortunately is becoming a lost art in and of itself. The second step is to learn how to obtain the components of bread, such as flour, water, and yeast.
If you are ready to go beyond the basic sourdough starter, try these yeast procurement methods for all new flavors and textures in your baking.

Read more here: http://www.offthegridnews.com/2011/0...our-own-yeast/

[MinnesotaSmith]

And, technically it's about fermenting yeast, not propagating it.

The difference is that yeast can only divide (reproduce) a certain # of times by fermentation metabolism, where it's growing without adequate access to oxygen. As few as eight divisions, or doublings, in a fermentation environment can make yeast be starting to get into trouble with its cell membrane health. The reason is that without enough oxygen (in combination with access to usable nitrogen), yeast cannot synthesize the unsaturated fatty acids it needs for cell membrane health and growth. This is more true for yeast in beverage ethanolic production, but is still somewhat a concern in yeast used for leavening.

True propogation of yeast involves something like one volume of air per volume of liquid (in the propagation vessel) per minute, a HUGE amount of air. Oxygen will still be the limiting factor, especially if fats are present. They interfere with oxygen transfer, and are both present in most foods. Most commercial defoamers are fats or oils of some kind, and yeast propagation is very vulnerable to enormous foaming problems.

I hope this gives some additional insight on the subject.

[grower]

Well, I don't understand all that you said, but I've been making sourdough bread from a starter that I keep in the refrigerator, and I know I've used it more than 8 times, and it's still working just fine. I do not seal it up, I either put it in a big clamp-seal jar with the clamp loose or in a mason jar with a napkin in place of the lid. So the air does circulate somewhat.

To be precise, you really can't "make" yeast -- it's a naturally occurring bacterium that's on just about any exposed surface. You can capture yeast, you can feed yeast, you can nourish and develop yeast. And from what I understand, this is what breadbakers and winemakers have been doing for centuries.

[DreadPirate]

Back before Y2K we tried tearing a fist size chunk of bread dough off and putting it in the flour bin. Then when we went to make bread again we would add that chunk to the mix instead of adding yeast. I forgot how many times we did this before we forgot to.
I can not remember where we read it but it worked great.
Just grab the chunk after the first rise.

[grower]

I guess that's how the old "sourdoughs" in California did it, during the Gold Rush. Didn't know if it would work that well, though. Thanks for the tip, DP!

[PyratePrincess]

anyone have any experiments with what i'd call "Lazarus dough"? (very old sourdough starter that has neither been fed or refrigerated)??

Guess what I found, lol It's just sitting on the counter. Laughing at me.