Yeast Is Yeast, and Homemade Is Best!

Our ongoing study of the monochromatic kingdom of non-flowering plants allows us to chalk up baking as science. I'm talking yeast here, peeps. (I love homeschooling!)

To get us primed we read through the lower book, Molds and Fungi, in one sitting (a very UN-Charlotte Mason thing to do. whoops.) Lots of facts in an easy-to-read format. I learned plenty myself.
The other book, Molds, Mushrooms, and Other Fungi, is more Dorling-Kindersley style with lots of pics and stuff. Darling daughter Mei freaked at both of them at times. Therefore, boys will love them.

Our science curriculum, Considering God's Creation, is neatly lining up with the monthly Outdoor Hour Challenges at Handbook of Nature Study where they're currently focusing on Lichens, Mushrooms, and Moss. (You can see our other entries on lichens here and fungus here.)Yeast, being a type of fungus like mushrooms, I figure it fits right in.

Fungi, we learned, grow by sending out hyphae, which are like little tentacles looking for food, usually in the form of something dead. Get enough hyphae, and you've got yourself a registered, incorporated mycelium. When these hyphae want to start a new colony, they shoot some spores into the atmosphere (e.g. your breathing space) and hope to colonize in the great beyond. But the work is done in the dark, mostly underground. It's happening everywhere and we should be glad of it cuz' if it weren't, well, in a nutshell, we wouldn't be here to tell about it.

Want to see a mycelium at work? You won't have to go far. Got a rotting woodpile? Matted dead leaves you forgot to rake? How about well-seasoned shredded mulch? That's where we found this:

My-oh-mycelium

The white stuff is not some sort of messed-up spider web. It's the mycelium full of hyphae. And it's eating away at that mulch. Which is why we have to keep replacing it every year.

Another place we were able to observe fungi was on the bread that we purposely let go for the sake of science. After over a week in a Baggie with a piece of old brie, we got this:

Calling Alexander Fleming

 Not like you've never seen that before (deliberately). But it makes for cool microscope study. We're also comparing the french bread with a piece of cinnamon bread (not shown) to see if cinnamon indeed retards spoilage. It seems it does!

Notebook page from Considering God's Creation

So back to that yeast. It does not do the hyphae thing. But is IS a fungus. I'm so glad we know how to use it. It makes some of my favorite things possible. Like bread. I recently got my second bread machine and have gotten back into this fun, healthy, delicious hobby. And the timing was PERFECT because we were going into this yeast study.

Yeast makes the bread rise simply by---well---burping. You feed it, it eats, it digests, and it burps. And the burps make the bubbles that make the bread rise. Doesn't sound so appetizing when I put it that way, but...

Now to coalesce science with baking even more, we had to grow some starter. A starter is a happy little town of live yeast that live in a jar, and that you feed and take care of.  (You can name yours. Ours is Fi-dough.) If you do a good job, the yeast will reward you by rising your next batch of dough. But this will be a different flavor because THIS yeast is SOURDOUGH! And it happens when those spores that a yeast fungus releases are caught and given a nice home of flour and water.

Baker's yeast. britannica.com

Want to try it? There are many, MANY places on the web that will teach you how to grow a starter. We ordered a fresh one for our purposes to ensure success. You can get some here. Did you know that they will taste different depending on where they are from? Because each region has a different yeast floating around in it! That's why a San Francisco Sourdough Bread can only call itself  S.F if the starter was actually grown IN San Fran!

Here, Mei is doing another experiment with some yeast to show how much it "burps." 
Mix a 1/2 cup lukewarm water with 2 teaspoons of sugar and 1 tablespoon of dry yeast (doesn't matter what kind.) Set it aside for 15-30 minutes.
If you do it in the ziploc bag, like we did, keep a close eye on it or you will get to experiment with cleaning starter off the walls.

Left: Mixing up the ingredients to grow yeast. Right, the proof! Ka-BOOM!

Before: cold from the frig

Here's another example of just how fast yeast can grow. We took some of our sourdough starter out of the frig and warmed it for just 30 seconds in the microwave. It increased in volume by at least 2 tablespoons just from being warmed up!

After 30 seconds in MW: frothy yeast.

 But here's the best experiment of all: a piping hot loaf of homemade sourdough bread. If only we had some taste-testers! Any volunteers?

Got yeast? Got comments? Tell Mother All About It!