I was hit by that craving again. This time for the kind of buttermilk I used to have in Bangalore. I guess it was all that talking I did yesterday about the Silicon Valley of India.
Buttermilk or Chaas in North India is different from its fiery-flavored South Indian counterpart. During hot summer days, women would manthan (churn) this brilliant piece of technology to get the best buttermilk for their families. 
In a less traditional set up, a handheld wood churner is used to make buttermilk. But if you have neither, use an electric blender like I did!
Ingredients for South Indian Buttermilk are:
1 cup plain yogurt
Two and half cups cold water
1 teaspoon grated ginger
1 teaspoon very finely chopped green chilies
2 teaspoons very finely chopped coriander leaves
1-2 teaspoons cumin seeds, dry roasted and crushed coarsely
Pinch of asafetida
Salt
In a blender, add the yogurt, water, salt and asafetida. Give it a whisk for about 30 seconds. Check on the seasoning.
To this mixture, add the chopped ingredients and the crushed cumin. Mix well with a stirrer. Pour in glasses. Serve immediately.
A lot of people in South India add a tempering of mustard seeds and curry leaves to their buttermilk too.
You can drink a glass of buttermilk to accompany a spicy Indian meal. But that’s not all, a buttermilk has huge possibilities in an Indian home. It can be served both as an apéritif and as an after meal digestif.
