Yes, dosa batter can be stored in the refrigerator after fermenting. Refrigeration slows down the fermentation process, preserving the batter for later use.
Once your dosa batter has fermented to your liking (typically indicated by a slight sour smell and increased volume), you can transfer it to an airtight container and store it in the refrigerator. The cold temperature significantly slows down the activity of the microorganisms responsible for fermentation. This prevents the batter from becoming overly sour or developing an undesirable taste. Properly refrigerated dosa batter can typically last for 3-5 days. Before using the refrigerated batter, allow it to sit at room temperature for about 30 minutes to an hour. This will help it regain some of its consistency and improve the texture of your dosas. Give it a gentle stir before using, as some separation may occur during storage.
To prevent the batter from becoming too sour during refrigeration, consider adding a small pinch of baking soda just before making the dosas. This will help neutralize some of the acidity and result in a lighter, crispier dosa. However, use baking soda sparingly, as too much can affect the taste and texture.