Properly fermented dhokla batter will have doubled in volume, appear light and airy with visible bubbles, and have a slightly sour aroma.
Fermentation is crucial for achieving the characteristic spongy texture of dhokla. Here's how to determine if your batter is ready:
Volume Increase: The most obvious sign is the batter's volume. It should have roughly doubled from its original size. This indicates that the microorganisms have been actively producing gas, which is essential for the airy texture.
Appearance: Look for a light and airy consistency. The batter should be bubbly and frothy. You should be able to see small bubbles throughout the mixture.
Aroma: A properly fermented batter will have a slightly sour, tangy smell. This is a result of the lactic acid produced during fermentation. If it smells overly pungent or off, it might be over-fermented or contaminated.
Texture Test: Gently stir the batter. It should feel light and fluffy. If it feels dense or heavy, it likely needs more time to ferment.
Fermentation time varies depending on the temperature. In warmer climates, it might take only 6-8 hours, while in colder climates, it could take up to 12-14 hours. Keep the batter in a warm place to encourage fermentation.