Yes, dhokla batter can be stored in the refrigerator after fermenting. This will slow down the fermentation process and prevent it from becoming overly sour.
Once your dhokla batter has fermented to your liking, you can store it in the refrigerator to halt further fermentation. The cold temperature significantly slows down the activity of the microorganisms responsible for fermentation. To store it properly, transfer the batter to an airtight container. This prevents it from absorbing odors from other foods in the fridge and also helps maintain its consistency. When you're ready to use the batter, take it out of the refrigerator and let it sit at room temperature for about 30 minutes to an hour. This will allow it to warm up slightly and regain some of its original texture. You might need to add a little water to adjust the consistency if it has thickened during refrigeration. Give it a gentle stir before steaming. Storing fermented dhokla batter in the fridge is a great way to prepare it in advance and enjoy fresh dhoklas whenever you want.
Don't store the fermented dhokla batter for more than 2-3 days in the refrigerator, as the fermentation process, although slowed, will continue and can eventually make the batter too sour.