Ammonium bicarbonate is a leavening agent used in baking, most commonly in thin, dry products like crackers and cookies. It works similarly to baking soda or baking powder, producing gas that makes dough rise, but it breaks down completely during baking and leaves no residual salt or flavor in the finished product. That clean decomposition is what makes it uniquely useful for certain foods, and it’s been a staple in commercial and traditional baking for well over a century.
How It Works During Baking
When ammonium bicarbonate is heated to around 60°C (140°F), it starts to break down into three gases: carbon dioxide, ammonia, and water vapor. At oven temperatures, this decomposition happens very quickly. All three gases expand within the dough, creating lift and an airy internal structure. At room temperature, the release of carbon dioxide is minimal, so the ingredient stays stable in raw dough or batter until it hits the heat of the oven.
This is different from baking soda, which needs an acid (like buttermilk or lemon juice) to react, or baking powder, which contains its own built-in acid. Ammonium bicarbonate doesn’t need any acid at all. Heat alone triggers the reaction, and because it produces three gases instead of just one, it generates more lift per gram than other chemical leaveners.
Why It’s Used in Crackers and Cookies
The catch with ammonium bicarbonate is the ammonia. In thin, dry products baked at high temperatures, the ammonia gas escapes entirely through the surface, leaving no trace behind. But if the final product retains more than about 5% moisture, the ammonia dissolves into that water and creates a sharp, pungent taste that makes the food inedible. This is why ammonium bicarbonate is restricted to low-moisture baked goods: crackers, thin cookies, biscotti, and similar items with a large surface area relative to their mass.
You would never use it in a cake, muffin, or bread. Those products are too thick and too moist for the ammonia to fully escape.
The Texture It Creates
Beyond simple lift, ammonium bicarbonate produces a distinctive texture that other leaveners can’t quite replicate. Biscuits made with it tend to have a more homogeneous internal structure with predominantly smaller, more evenly distributed pores. Research published in the Journal of Food Science and Technology found that compared to biscuits made with other baking powders, those made with ammonium bicarbonate had the least hard structure, the highest spread, and the most uniform surface appearance.
That combination of lightness and even porosity is why these biscuits absorb liquid particularly well. The researchers described them as ideal “dunking biscuits,” absorbing more milk during soaking than biscuits made with other leaveners. Biscuits made with tartaric acid-based baking powders, by contrast, were crisper but scored lower in overall sensory acceptability. If you’ve ever eaten a European-style cookie that practically dissolves when dipped in coffee, ammonium bicarbonate is likely the reason.
Regulatory Status
The U.S. Food and Drug Administration classifies ammonium bicarbonate as Generally Recognized as Safe (GRAS) under 21 CFR 184.1135. It’s approved for use as a leavening agent, dough strengthener, pH control agent, and texturizer. There is no specific concentration limit set by regulation. Instead, it falls under the standard of “current good manufacturing practice,” meaning manufacturers can use as much as needed for the intended effect, but no more.
This broad approval reflects the fact that the compound breaks down entirely into gases during baking. Unlike sodium bicarbonate, which leaves behind sodium salts in the finished product, ammonium bicarbonate leaves nothing behind when used correctly in appropriate products.
The Acrylamide Concern
One area where ammonium bicarbonate has drawn scrutiny is acrylamide formation. Acrylamide is a potentially harmful compound that forms naturally when starchy foods are baked or fried at high temperatures. Ammonium bicarbonate contributes to this process by acting as an additional source of nitrogen and by indirectly promoting the chemical reactions between sugars and amino acids that generate acrylamide.
Because of this, food scientists have explored replacing ammonium bicarbonate with alternatives in products where acrylamide levels are a concern. Substitutes include sodium bicarbonate paired with acidulants like tartaric acid or citric acid, or potassium bicarbonate combined with other acid salts. These alternatives reduce acrylamide levels but don’t always produce the same texture. For manufacturers, it’s a tradeoff between minimizing a contaminant and preserving the light, even crumb that ammonium bicarbonate delivers.
Where You’ll Find It on Labels
Ammonium bicarbonate appears on ingredient lists under its own name or sometimes as “ammonium hydrogen carbonate” or the E number E503(ii) in European products. It’s common in commercially produced crackers, flat cookies, and traditional European baked goods like German Lebkuchen and Scandinavian holiday cookies. Some recipes still call for it by its old-fashioned name, “hartshorn salt,” a reference to its historical production from deer antler shavings.
If you’re buying it for home baking, it’s typically sold as a fine white powder in specialty baking shops or online. Store it in an airtight container, because it slowly releases ammonia even at room temperature and will lose potency over time if exposed to air. You’ll know it’s still active if it has a faint ammonia smell when you open the container.