They make gas and aerate the dough. Soda works the instant it meets acid; yeast takes hours. They are not interchangeable.
Soda does nothing without acid, and the excess tastes of soap. Yeast dies at 55 °C — test the water on your wrist.
This profile is for double-acting phosphate baking powder; use the label for brands with different acids or starch carriers.
How to keep it, and who it suits.
Keep the unopened container in a cool, dry place for 18 months; after opening, seal tightly and use within 6 months.
The starch carrier and shared-line information vary by baking-powder brand; verify the label.
Allergen: GLUTEN
This ingredient carries no meaningful carbohydrate, so it has no glycaemic index. On its own it will not move blood sugar; what you eat alongside it decides that.