My rice cooker usually boils over. Why are there bubbles forming when I cook instead of just steaming?!

My rice cooker usually boils over. Why are there bubbles forming when I cook instead of just steaming?

I am using a black and decker rc450. I have tried brown rice, white rice, long and short, distilled water, tap water, with butter and without, in just about all the combinations. I have washed it out and made sure that the soap is fully rinsed but no success. I have to clean up quite a bit of a mess when the rice is done each time.

Try adding a small amount of olive oil (no need to spring for extra virgin) to the water. This will help prevent boilovers. You could also try one of those clay things that prevent boilover.