After cooking the Black Glutinous Rice Sweet Soup, why are there brownish red stains at the bottom?

After cooking the Black Glutinous Rice Sweet Soup, why are there brownish red stains at the bottom?

Using the magic cooker for desserts is convenient that you don’t need to keep an eye on the cooking. Safe and time saving! However, why are there brownish red stains at the bottom after cooking certain ingredients, for example, red beans, black glutinous rice and black beans?

Don’t panic! The brownish red stains come from the natural dye of the food. You may clean them with regular detergent and sponge.

*Using sponge can avoid serious scratches