Double Acting Aluminum Free Gluten Free Kosher All NaturalBob"s Red Mill Double Action Baking Powder releases carbon dioxide when exposed to moisture and heat, causing doughs and batters to rise. It is all natural and contains no aluminum. Baking powder is perishable and should be kept cool and dry.Bob"s Red Mill products labeled Gluten Free are batch tested in our quality control laboratory. We use an ELISA Gluten Assay test to determine that a product is gluten free.