Don't be alarmed if you combine orange juice and baking soda and find it fizzes. This reaction means that the baking soda is fresh and is actively working. Combine this mixture quickly with flour, sugar, eggs and other ingredients to make light, fluffy cookies, muffins or cakes.
Baking soda is a highly alkaline substance derived from trona ore, most of which is mined in the Green River Basin in Wyoming. When baking soda interacts with an acidic substance, it creates sodium carbonate and carbon dioxide. Carbon dioxide bubbles give lift to cookies, cakes and other baked goods. If a baked good doesn't contain an acidic ingredient, the baking soda may not dissolve completely. Baked goods may be flat and have a bitter taste. You may even notice bits of undissolved baking soda in the baked good.
Vinegar combined with baking soda makes for spectacular science experiments in elementary school, but it's not the only acid capable of making baking soda fizz. In baked goods, buttermilk, molasses, brown sugar and even most fruit juices and purees interact with baking soda. Orange juice is more acidic than most fruit juices and can certainly cause a reaction.
Mixing orange juice with baking soda probably won't have the explosive power of vinegar and baking soda, but it can still make a mess. Bypass this problem by changing your method of mixing. If you're making orange cookies or an orange cake, blend the orange juice with the other wet ingredients, such as the butter, eggs or oil. Sift the baking soda into the flour. The baking soda and orange juice will meet only after they've been mixed into a batter. The batter contains the bubbles and eliminates any mess.
Baking soda needs both an acidic ingredient and heat to work properly, which is why it's important to get baked goods into the oven fairly quickly. If you put baking soda in a glass of orange juice and left it on the counter, the bubbles would dissipate quickly and the orange juice would return to normal. Another reason baking soda sometimes doesn't work is because it's old. Keep baking soda in a dry, cool location and replace it at least once each year.
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