Soaking brown rice, oats seeds grains

There are raw oats in muesli so I don't think there would be a problem with sprinkling them on your soup.

The articles also said to soak muesli.

My Scottish nephews eat raw porridge stirred into cold milk for breakfast so I'm sure raw would be fine..

Have raw oats, milk and banana most days for breakfast. Like muesli really but without added calories from dried fruit and nuts. Not sure if that would work stirred into soup, perhaps it would just sink, although oat bran may be a better solution as it is finer.

When porridge was always made with oatmeal, you did have to soak the grains overnight. These days it is all rolled flaked oats, which has already been steamed to expand it, rather like popcorn, before it is flaked and rolled. (At least I think so! We had a friend who worked for Scotts Porage Oats and that is what I remember. I could be completely wrong)

Rolled oats cook in a few minutes.

It's also to do with making them more digestible, getting rid of phytates and releasing more enzymes.

Oats: A grain, which in England is generally given to horses, but in Scotland appears to support the people. (Doctor Johnson's Dictionary, 1755)

Damn good stuff. It lowers your cholesterol level and it keeps you reg'lar.

You never see a horse taking statins.

I have eaten porridge oats raw, but not lately.
I never soak rice before cooking, or lentils, but always soak other dried pulses such as barley, beans.