What is the ideal fermentation time and temperature for idli/dosa batter to achieve a perfect sour tang without it becoming overly acidic?

Question

What is the ideal fermentation time for idli/dosa batter? Learn how to achieve a perfect sour tang without the batter becoming overly acidic.

Answer 1

The ideal fermentation time for idli/dosa batter is typically 8-12 hours at a temperature of 24-30°C (75-86°F). This allows for optimal lactic acid production, resulting in a balanced sour taste.

Detailed Explanation:

Fermentation is a crucial step in making idli and dosa, as it develops the characteristic sour flavor and light, fluffy texture. The process relies on beneficial bacteria, primarily *Leuconostoc mesenteroides* and *Streptococcus thermophilus*, which convert carbohydrates in the rice and lentils into lactic acid. This acid lowers the pH of the batter, creating the desired sourness.

The ideal fermentation time depends on the ambient temperature. At warmer temperatures (28-30°C), the fermentation process accelerates, and the batter may be ready in 8-10 hours. In cooler environments (24-26°C), it may take 10-12 hours or even longer. Over-fermentation leads to excessive lactic acid production, resulting in an overly sour and sometimes bitter taste. Under-fermentation, on the other hand, will result in a dense and less flavorful idli or dosa.

To determine if the batter is properly fermented, look for these signs:

1. The batter should have increased in volume, typically doubling in size.
2. It should have a slightly sour aroma.
3. The batter should be light and airy, with small bubbles visible throughout.

If the batter ferments too quickly, you can refrigerate it to slow down the process.

Pro Tip:

Adding a small amount of fenugreek seeds (methi) while grinding the batter can aid fermentation and impart a subtle, pleasant flavor. However, use it sparingly, as too much can make the idlis bitter.