The Leavening Lab: Mantou Yeast Balloon Inflatables

The Leavening Lab: Mantou Yeast Balloon Inflatables

Those soft, fluffy mantou (steamed buns) owe their delightful texture to a tiny, industrious organism: yeast! Making mantou can be a fun, hands-on experiment to measure carbon dioxide (CO2) production and observe the power of fermentation in action, almost like inflating a balloon!

Yeast are single-celled fungi that, when given warmth, moisture, and sugar, perform a process called fermentation. During fermentation, yeast consumes sugars and produces two main byproducts: alcohol (which mostly evaporates during cooking) and carbon dioxide gas.

In mantou dough, this CO2 gas gets trapped by the elastic network of gluten. As the yeast produce more and more gas, tiny bubbles form throughout the dough, causing it to "rise" and become airy and light. You can see this in action by putting some warm water, sugar, and yeast in a bottle and stretching a balloon over the opening. As the yeast ferment, the balloon will inflate from the CO2 gas they produce, showing you the invisible force at work in your dough. This controlled CO2 production is what transforms a dense lump of dough into a beautifully light and fluffy mantou, making it a delicious example of microbiology in action!