Creating more yeast is similar to making a sponge for potato bread.
1 large potato peeled and sliced
1/2 cup flour
1/2 cup sugar
1 teaspoon ginger
3 packets yeast (not rapid-rise)
2 cups cornmeal
Boil the potatoes until soft. Strain, reserving the liquid. Mash the potatoes with a little of the reserved liquid.
Mix 1 cup of mashed potatoes with the flour, sugar ginger and yeast. Add 1/2 cup of the reserved cooking liquid. Make sure the the liquid has cooled a bit, too hot and it will kill the yeast. If you are not use to testing the heat with your finger use a thermometer. The temp should be 110F - 115F.
You should have a pancake batter. Set aside to rise and bubble.
Place the cornmeal on a cookie sheet and set into a low temp oven for about an hour. Do not brown it merely dry it out.
Once the pancake looking batter has risen and is bubbly, you want to mix the cornmeal in with it. Slowly. You don't want the batter to dry out too much. turn out your dough, and use some of the cornmeal to help roll out the dough. You want to get it as thin as possible.
At this point you can cut out cakes with a cookie cutter or leave whole for a crumble. For the crumble you want to occasionally take a fork to it and "fluff" it. Separating it. Depending on the humidity in your home this can take up to several days or only a few hours.
Once dried put into a quart container and place into your freezer. If making cakes, they have to be individually wrapped. 6 months is the recommended time but can stay fresh for up to 1 yr. Once you are running low, repeat the process using your homemade yeast.
Stock photo. mine still isn't dry
To use, bring desired amount to room temp.