Single Action Baking Powder can be either heat or moisture activated.
Heat:
- Allows you to mix a liquid, batter or dough below say 30 degrees and keep it to use all day or even the next day. The reaction will start in the oven or fryer or griddle only.
Moisture:
- Use in dry mixes. Will only start reacting when blended with liquid eg dry pancake mix, instant sponge mix.
- Use in liquid mixes when you will use immediately.
With both heat and moisture activation, each can be balanced to react at a low or high level of moisture or heat and a slow or fast reaction rate. Particle size and encapsulation can help but it is easier to use multiple types to suit what is required by the end product.
For you to try at home:
If you used double acting (our) baking powder and made a bowl of pancake/flapjack mix you should leave the mix for 60 mins in the fridge and then gently scoop the mix onto a hot plate to cook, then take another scoop of milk and stir it then put on the hot plate and cook. You should see the first one with moisture bubbles and heat bubbles is the nicest, biggest and fluffy. The other one you knocked out the moisture bubbles and only used heat bubbles will be dense, lower volume and more chewy. It will give you some idea of effect of baking powders.