Baking
Baking Soda Conversion
Baking Soda weighs 221g per US cup.
Conventionally measured by the teaspoon.
| Amount | Grams | Ounces |
|---|---|---|
| 1 cup | 221.0 g | 7.80 oz |
| 1/2 cup | 110.5 g | 3.90 oz |
| 1/4 cup | 55.3 g | 1.95 oz |
| 1 tbsp | 13.8 g | 0.49 oz |
| 1 tsp | 4.6 g | 0.16 oz |
| 100 g | 100.0 g | 3.53 oz |
Need a different amount? Use the full Ingredient Converter tool.
At 221 grams per cup, baking soda is heavier than most of the leaveners it sits alongside on this site, but the number is really just arithmetic — pure sodium bicarbonate is so alkaline in concentration that even a slight overmeasure by teaspoon can push a batter toward a soapy, metallic aftertaste, so a cup-scale quantity is never what a recipe intends.
Unlike baking powder, baking soda has no acid built in — it's a single, pure compound that needs an acidic ingredient already present in the recipe (buttermilk, brown sugar's molasses, yogurt, lemon juice, or natural cocoa powder) to react and produce the carbon dioxide gas that provides lift, which is exactly why a recipe using baking soda as its only leavener always contains something acidic alongside it.
Because that reaction happens quickly on contact with both moisture and acid, a batter leavened with baking soda generally needs to go into the oven soon after mixing — unlike a double-acting baking powder recipe, which gets a second lift once heated, baking soda's gas release front-loads into the mixing stage, so unnecessary delay before baking can mean losing some of that lift before it counts.
Baking soda is measured in teaspoon quantities in virtually every recipe that calls for it, so its 220g-per-cup figure functions purely as a scaling reference — unlike baking powder, baking soda needs an acidic ingredient present in the recipe (buttermilk, brown sugar, cocoa, vinegar) to activate its leavening reaction at all.
Baking soda used without enough acid present in a recipe can leave a distinctly metallic, soapy aftertaste — a common sign of an imbalanced recipe rather than a flaw in the baking soda itself, since the compound needs an acid to fully neutralize into carbon dioxide gas.
Frequently asked questions
Why does baking soda need an acidic ingredient to work?
It's a pure alkaline compound (sodium bicarbonate) with no acid of its own — it needs to react with an acid already in the recipe (buttermilk, molasses, yogurt, lemon juice) to release the carbon dioxide gas responsible for lift; without that acid, it won't leaven properly and can leave a soapy aftertaste.
What happens if I use too much baking soda in a recipe?
Excess unreacted baking soda leaves a distinctly bitter, soapy, metallic taste, and can also cause a baked good to rise too fast and then collapse — precision matters more with baking soda than with many other pantry ingredients precisely because the margin for error is narrow.
Can I substitute baking powder for baking soda in a recipe?
Not reliably 1:1 — baking powder is weaker per teaspoon and already contains its own acid, so a straight swap changes both the leavening power and the recipe's acid balance; a recipe built around baking soda's reaction with a specific acidic ingredient doesn't translate cleanly.
Does baking soda expire?
Not in the sense of becoming unsafe to eat, but its reactive punch fades over time, especially once opened and exposed to kitchen humidity — mix a spoonful with vinegar and watch for a vigorous fizz; a weak, sluggish reaction means it's time for a fresh box.
Is baking soda the same thing used to deodorize a refrigerator?
It's the same compound, sodium bicarbonate, but once a box has been sitting open in the fridge absorbing odors, it's no longer appropriate for baking — always use a fresh, dedicated box for cooking rather than repurposing the fridge deodorizer box.