Bob's Red Mill Double Acting Baking Powder is a leavener used for baking. It releases carbon dioxide when exposed to moisture and heat, causing dough and batter to rise. It is gluten free and contains no added aluminum. Unlike many other baking powder brands that utilize sodium aluminum phosphate or sodium aluminum sulfate as the acid ingredient, our baking powder substitutes monocalcium phosphate and sodium acid pyrophosphate to create a superior double-acting baking powder without the metallic aftertaste. And like all our gluten free products, our natural baking powder is produced in our gluten free facility and batch tested to ensure its purity. Our baking powder is perishable and should be kept cool and dry. Product Features : Brand: Bob's Red Mill Seasoning Form: Milled Type: Mixed Spices Seasonings Size: 397 gm Packaging: Pouch Expirable: Yes