How to Invent Everything: A Survival Guide for the Stranded Time Traveler

by Ryan North

By adding some yeast to your flour/water mixture and letting it sit for a few hours before cooking, you will produce leavened bread. This works because the yeast you’ve selected for are bred to feed on the sugars in your flour and water, and if there’s oxygen around, they’ll produce carbon dioxide as waste. This carbon dioxide is trapped by the gluten in your flour, where it causes your bread to rise. When you cook your dough, the yeast will happily keep gorging themselves in the food utopia you’ve given them, right up to the point where things become so hot that they all die as their entire colony is cooked to death. Congratulations! You have used the labor of microscopic animals to produce a more pleasant bread, then killed them the instant they were no longer useful. Millions of these microscopic animal corpses are baked into every slice of bread you eat.