Dear Rabbi,

I like to keep my sale of chametz to a non-Jew on Pesach to a minimum, so we're already timing carefully our purchase of foods that contain chametz that we buy in bulk. My question: We buy dog food in big sacks, and I've checked the ingredients for chametz. The only suspect ingredient is "brewer's yeast." Since I understand that not only can I not eat chametz, but neither can my dog, can you tell me if brewer's yeast is chametz?

Dear Eliyahu Shiffman,

A kashrut expert told me that nearly all brewer's yeast is made from beer production and is chametz.

The reason you can't give your dog chametz on Pesach is that you are not allowed to own chametz, or to derive benefit from it.