Mixing bowls come in different sizes and materials, including glass, ceramic, plastic, and stainless steel. We prefer wide heavy-duty stainless steel bowls that make mixing easy. Stainless steel bowls are nonreactive and very durable; a set of six nested bowls from small to large will cover most baking needs. Use glass mixing bowls for melting chocolate and for anything else you want to pop in the microwave to warm.