How to know if dosa batter is spoiled?

In this article, we will answer the question “How to know if dosa batter is spoiled?”, how to make idli dosa batter, and how to ferment the idli dosa batter in a cold climate. 

How to know if dosa batter is spoiled?

The dosa batter is spoiled if it turns sour, smells bad, or develops a thick yellow layer on top. If everything else is good, the sourness can be countered to some extent by mixing rice flour, hot water, or cooked rice into the batter. But the smell won’t be entirely gone. 

Extra sourness is a sign the batter is over-fermented. You can avoid this by reducing the amount of urad dal, and fenugreek seeds, or by placing the batter in a cold spot such as the fridge.

How to make Idli Dosa batter?


  • 1 cup Urad Dal
  • 3 Cups Idli Rice / Ukda Chawal /Rice
  • 1/4 tablespoon salt 
  • 1 tablespoon of Methi Dana (Fenugreek Seeds)

The addition of salt is compulsory if you live in a cold climate as it promotes fermentation. Otherwise, you can skip the salt or better yet, add it towards the end of fermentation to make the batter last longer. 


  1. Rinse the urad dal and methi under cold running water for about 2-3 minutes or until the water runs clear.
  1. Wash the rice in a separate bowl for 2-3 minutes or until the water runs clear.
  1. Soak the idli and methi in one bowl. Use a separate bowl to soak the rice.
  1. Blend the soaked urad dal with water until nice and smooth. Do not overdo the water because we are not looking for a runny consistency. 
  1. Then stir in ¼ tsp of salt and leave to ferment. Fermentation takes about 16-24 hours if you live in a cold climate. 
  1. Make idlis or dosas out of the fermenetd batter.

How to ferment the idli and dosa batter in a cold climate?

There are a few tips you can follow if you want to ferment your idli and dosa batter in a cold climate. These tips will allow you to make a fluffy idli batter. 

Grind the grains separately 

The first tip is to always grind the urad dal and rice separately using as little water as possible. Start with a tablespoon and then work your way up in teaspoons. This helps the grains ferment easily. However, for making dosa, you may grind both grains together. 

Use the golden ratio 

Mix rice and dal in the golden ratio of 3:1 ratio, respectively. 

Type of dal and rice 

The type of dal you use is very important. Usually, all types of urad dal, namely split, whole, or black, would work perfectly fine. For the rice, prefer using the idli rice for the best results.

Add leftover rice to the batter 

Adding ¼ cup of soaked poha or leftover rice while grinding the batter for idlis promotes fermentation, which will result in crispy dosa.

Create a warm environment 

There are three ways to go about it. 

1- Place the batter, wrapped in a blanket, in a warm area, or any spot where the container is in indirect contact with the sunlight. The problem with this method is that you might end up with a messy blanket when the batter inflates.

2- Put the container in the oven with the oven light on for about 2-3 hours. The heat from the light will provide sufficient heat to kickstart the fermentation. 

Alternatively, you can heat the oven and then turn it off. When the oven reaches a warm temperature, place the batter inside the oven. If you have just taken out a baked product from the oven, you are in luck. Use the residual heat of the oven to ferment your dosa batter. Make sure the oven is warm and not hot. 

3- Place the container near a heat radiator if you have one.

Considerations about the container 

Leave the batter container undisturbed. Do not lift its lid now and then and do not open the oven door. Choose a glass or steel container for the best results. Last but not the least, place the container on a plate or dish to catch the batter in case it overflows. 

How to store and use the batter after fermentation?

Let the dosa or uttapam batter rest in the fridge for about 2 days before making dosas out of it. This will make sure your dosas turn out crispy. Discard the idli and dosa batter after 4-5 days of refrigeration. 


In this article, we answered the question “How to know if dosa batter is spoiled?”, how to make idli dosa batter, and how to ferment the idli dosa batter in a cold climate.


What was missing from this post which could have made it better?

Leave a Comment