Batters to be ground may be done either in mixers, or by stone grinders, the electrical versions are now a household name. In India however, there are still many areas where there are grinding shops who will grind you batter for you in their wet grinders, for a very nominal, charge, and save you a great deal of hassle. They are a godsend! However the best results are still got from the traditional stone grinder, operated by hand. Cheers for the stone age, and for those who have the time, this procedure tones your biceps, arms and upper back like no other exercise!
Make sure to add water a little at a time, to batters. This allows the incorporation of air so important in making the end product light and fluffy. To much water added right at the beginning will only make the batter liquid fast, but heavy since air will not get incorporated into it.
Make sure to add salt to wet batters just before you use the it. This is if you plan to refrigerate the batter and use it much later than its regular usage period. Cover the batter with a banana leaf while refrigerating. This will keep the batter from getting sour sooner.
With all dosa batters one may make the thin papery crisp dosas or the fluffy thick soft one, depending on how you spread it on the skillet. Allow the thick ones to cook covered on a low flame.