Apple cores and banana peels are more than just compost!
I used to buy yeast in bulk from an Amish store for super cheap – I got a whole container for $1! I have since moved, and now I am stuck with expensive grocery store yeast. That is when I realized I could collect my own yeast from the natural pores floating around the air. Here’s how:
Save a jar (preferably glass) after it is emptied of its contents. I have tons from pasta sauces and nut butters. Fill it with 1-2 cups of water and add various dried fruits, apple cores, banana peels, carrot peels, or whatever type of sweet fruit/vegetables you have on hand.
Lightly screw on a lid, but do not make it airtight. Let sit for several days until the water turns cloudy and there is white stuff floating around. In the cold winter this could take a week or more, in the summer this may take just a few days.
If the yeast water is ready before YOU are, stick it in the fridge until you want to use it. Warm up to room temperature before using. I zap mine in the microwave for 30 seconds, but I have to be careful because if it gets too hot the yeast dies. So far I have used mine to make pita, but feel free to leave the yeast out of any recipe and replace all or some of the liquid with yeast water. Experiment, see what happens, and share your findings!