To make the pastry look lush and airy. Soda alone will not provide this. To do this, it must be combined with acid, that is, extinguished. Then bubbles of carbon dioxide are formed, thanks to which the baking will increase in volume.
In addition, soda in its pure form or undecomposed soda can give the dish an unpleasant bitter‑salty taste.
There are two options: first combine the soda with acid and then add this mixture to the dough, or mix the soda with other dry ingredients and pour all the necessary liquid into them. Many housewives believe that the second method does not allow carbon dioxide to evaporate, which means that the interaction occurs after kneading the dough and it turns out more lush.
Most often, soda is extinguished with table 9% vinegar. The approximate proportion is 2 : 1, that is, for 1 teaspoon of soda, you need to take 1 teaspoon of liquid.
Lemon juice or apple cider vinegar in the same amount will also be great.If there is a fermented milk product in the dough, then additional acid is not required. Kefir, sour cream or other similar ingredient is enough to cause a reaction.