Is Yellow Dal Safe?
The yellow dal we can purchase in Indian groceries is green gram (mung dal) that is split with the outer green hull stripped off. It is considered a very healthy food in Ayurveda. The combination of rice plus yellow dal is considered almost ideal.
However, I have been questioning that opinion for a while. My first reason for quesitoning it was simply from the whole food perspective. We know that whole grains have more nutrients than refined grains. Is that same thing true for "refined" beans? Split yellow mung dal is certainly refined compared to whole green mung dal (green gram). Ayurveda says that the yellow dal is easier to digest (and a great variety of health problems can be traced back to subtly incomplete digestion).
However, prior to resolving that question, I have found a new reason to doubt the split yellow dal I have been buying at my local Indian grocery store. When I wash it, it creates endless soap-like bubbles. My logic is that they must use a strong chemical or soap to remove the outer green hull. They probably soak the beans in this chemical when they strip off the hull. Whatever it is, it will not go away by simply washing the yellow dal.
Try it yourself and let me know if you see the same thing. Put some dal in a strainer. Sit the strainer on a container or pot so that the mesh holding the dal is inside the pot. Fill the pot with water, and then use your sink sprayer to wash the dal vigorously. When I do this, I see a lot of bubbles and a foam substance that resembles dirty sea foam. No matter how many times I rinse the dal, the foaming continues.
When I cook the dal, boiling it produces more foam and bubbles. At first I wondered if this were due to a property of the bean. However, when I wash and cook whole green dal, none of this foaming happens. There are no soapy bubbles either.
I have tried several brands of yellow dal (my Indian grocery sells a few different brands) and I have tried several brands of green dal. The comparison was the same as I described above in each case.
Furthermore, it is impossible as far as I can tell to get organic yellow dal at this time. However, I have a couple sources for organic green dal. My favorite source is Purcell Mountain Farms at this link.
Even though I do not yet know if whole green dal has more nutrients or more fiber (I am guessing it does), I have decided to stop eating split yellow dal because of the soapy/foamy stuff I see when I rinse, it together with the fact that I can only get organic dal in the whole green type.
I cook the green dal well and I feel that I am able to digest it just fine. However, I do realize that the topic of complete digestion in Ayurveda is very, very subtle. It has little to do with issues like indigestion, and everything to do with extracting the subtle qualities from the foods. So this issue remains open to further research. If I find out something new about complete digestion in Ayurvedic terms that convinces me removing the hull has value that offsets the loss of nutrients - and if I can get yellow dal that is free of chemicals or soaps, I'll revisit my decision. But for now - it is only whole green dal for me.