What is the thin, colorless film that remains after making oatmeal?

Question

When I cook ground oatmeal with boiling water, a thin colorless film is formed around the interior surface of the pot. The film comes off the pot easily, but it is attached and rooted into the cooked oatmeal. It is colorless and very similar to a thin plastic wrap. It easily breaks off into smaller pieces and it could also melt into the oatmeal.

I don't know if this is coming from the pot's material (unsafe), or is it just the water and oat fibers combining to create it (safe). The pot looks completely undamaged and fine. Is this normal? I am just worried about safety. Thank you for any feedback!

Answer 1

Finely ground oatmeal forms a colloid in water. When that dries at the surface, you get a skin. Colloidal oatmeal feels a little odd in the mouth, but is perfectly edible. It's been used medically to treat skin irritation at least back to the 1800's.