For what dishes I should wash starch off red lentils?

Question

I usually wash grains and beans before using them. I wonder how/for what dishes I should wash red lentils?

When I washed them, the water looks "soapy" (lots of foam) until I change it cr. 8 times. According to this blog, this is a correct procedure, I should wash the lentils until the water runs clean (i.e. no foam). But obviously, it takes time, and starch (?) is sometimes beneficial for the dishes.

So my question is: for what dishes I should wash red lentils until the water becomes clean, and for what I should wash just once or twice, to wash off the dust? Dished I have used red lentils so far are red lentil burgers (cooking them in boiling water, mashing, forming patties, and then pan-cooking them), and Dal Adas (soup).

Answer 1

The main reason why you rinse lentils and beans is to remove debris or shriveled lentils. Also for hygiene reasons, depending on where and what lentils you bought, they might include little stones, sand, or dust.

In general, if you don't rinse your lentils/beans they will foam more while cooking. The foam is caused by starch and denatured protein from the beans.

Rising your beans or lentils does reduce the foaming.

As a result for dishes where you’re not planning on draining the lentils (for example, you want to add extra veggies to make a tasty lentil soup), you probably don’t want to have foam floating on top and I would recommend to rise and/or soak your beans and lentils.

For dishes where you're just cooking lentils on their own, you’ll probably end up draining the liquid away once they’re cooked, so the majority of the foam will be drained away anyway and you don't necessarily need to rinse your beans/lentils.

Some people say that rinsing or soaking the beans/lentils also helps against flatulence, etc. but there is no real evidence for that as it seems. I only have been able to found a roughly related study from Harvard here.

I hope this helps! I found a lot of forum/chats and blog articles that argue the pros and cons of rinsing but the reason above seems to be receptively the main reason and is also my own experience.