Baking Soda vs Baking Powder: What's the Difference and When to Use Each

By , B.Sc. Chemistry, M.Sc. Environmental Science · FoSTaC certified (Advanced, Manufacturing)6 min read
SALINE food grade baking soda 1kg pack, front of pack

Baking soda is pure sodium bicarbonate, an alkali. On its own it does very little; it needs an acid, such as curd, buttermilk, lemon juice, vinegar or tamarind, and moisture to release the carbon dioxide that lifts a batter. Baking powder is baking soda already mixed with dry acids and a little starch, so it needs only moisture, and often heat. Soda is the stronger of the two: about ¼ teaspoon of baking soda does the lifting of 1 teaspoon of baking powder (NC State University).

Key Takeaways

  • Use baking soda when the recipe already contains an acid; use baking powder when it does not.
  • Baking soda is roughly four times as strong, so the two are not swapped spoon for spoon.
  • Too much soda tastes soapy and bitter, and turns haldi in a batter red.
  • Both lose their lift with age and damp: test them before an important bake.

What is baking soda?

Baking soda is sodium bicarbonate (sodium hydrogen carbonate, food additive number INS 500(ii)). When it meets an acid in a wet batter, it reacts and releases carbon dioxide. The bubbles expand in the heat of the oven or steamer and set into a light crumb. Because the reaction starts as soon as the acid and soda meet, a soda batter should be baked or steamed soon after mixing.

What is baking powder?

Baking powder is a ready-made mix of three things: baking soda, one or two dry acids, and starch to keep the mix dry in the tin. Most powders sold today are double-acting. One acid, such as monocalcium phosphate, reacts as soon as the powder gets wet. A second, such as sodium acid pyrophosphate or sodium aluminium sulphate, reacts only once the batter is both wet and hot (NC State University). That second rise is why a baking powder batter can wait a little before it goes into the oven. On Indian packs these acids appear as additive numbers, such as INS 450(i) and INS 341(i).

Baking soda vs baking powder at a glance

Baking soda Baking powder
What it is Sodium bicarbonate only Baking soda + dry acid(s) + starch
Needs an acid in the recipe? Yes No, it brings its own
Strength Strong: about ¼ tsp Milder: about 1 tsp for the same lift
When it reacts As soon as it meets acid and moisture Partly when wet, partly in the heat
Effect on colour and taste Helps browning; soapy if overused Neutral when measured correctly
Typical use Recipes with curd, buttermilk, lemon or cocoa Recipes made with milk or water

When should I use baking soda, and when baking powder?

  • The recipe has an acid (curd, buttermilk, lemon, vinegar, tamarind, natural cocoa): baking soda, which uses up that acid.
  • The recipe has no acid (milk, water, plain flour): baking powder.
  • Both are listed: the soda neutralises the acid in the recipe and the powder adds the rest of the lift. Many eggless cakes made with curd use both.

How is baking soda used in Indian cooking?

Dish How soda is used
Dhokla and khaman Stirred into the besan batter with lemon juice or citric acid just before steaming, for a spongy set
Bhatura and kulcha With curd in the dough, for soft, puffy bread
Pakora and bhajiya A small pinch in the batter for a lighter, crisper coating
Jalebi A pinch in some quick batters that are not fermented overnight
Chole and rajma A pinch in the soaking or cooking water to soften the skins

In each case, a little goes a long way. A pinch for a batter, or about ¼ teaspoon per cup of flour in baking, is the usual starting point; follow the recipe. For more, see our baking soda guide.

Can I use one instead of the other?

Baking powder instead of soda: use about three to four times as much, so 1 teaspoon of powder for ¼ teaspoon of soda. It is approximate. The powder brings its own acid, so the result can taste slightly tangier and brown less.

Soda instead of baking powder: you have to add the acid yourself. A common swap for 1 teaspoon of baking powder is ¼ teaspoon of baking soda with ½ teaspoon of cream of tartar (McCormick). Without cream of tartar, replace some of the liquid with curd or buttermilk, which are acidic.

What happens if I use too much baking soda?

  • A soapy, bitter or metallic taste. This is leftover soda that no acid has used up.
  • Red patches in dhokla or khaman. Haldi is a natural pH indicator and turns red in alkaline conditions, so red streaks mean too much soda or too little acid.
  • Darker, coarser bakes. Extra alkali speeds up browning and can make a cake rise fast and then sink.

Does cooking vegetables or pulses with soda affect nutrients?

Yes. A pinch of soda keeps green vegetables bright and softens chickpeas and rajma, but the alkaline water destroys some of the vitamins, especially vitamin C, and the effect is on top of ordinary losses from boiling (Chemistry LibreTexts). Use only a pinch, or skip it for vegetables and soak pulses overnight instead.

How do I know if my baking soda or baking powder still works?

  • Baking soda: stir ¼ teaspoon into two tablespoons of vinegar or lemon juice. It should fizz hard straight away.
  • Baking powder: stir ½ teaspoon into a few tablespoons of hot water. It should bubble vigorously.

A weak fizz means the pack has picked up moisture. Keep both tightly closed in a cool, dry place, away from the steam of the stove. Baking soda also absorbs odours, so keep it away from strong spices.

Does it matter if baking soda is food grade?

Yes. Sodium bicarbonate is also sold in technical and industrial grades for cleaning and manufacturing. Only food grade is meant to go into food. If you use baking soda for cleaning as well, keep a separate pack for the kitchen.

Our food grade baking soda is pure sodium bicarbonate in a 1 kg pack, for cakes, dhokla and khaman batters, and around the home. More answers are in our FAQ.

This article is about cooking and baking. Use food grade baking soda in food, and follow your recipe's quantities.

Sources

  1. Explainer on how baking soda and baking powder work. NC State University News, May 2014. news.ncsu.edu
  2. McCormick. If you're out of baking powder or baking soda, try these substitutes. mccormick.com
  3. Determining vitamin C in foods. Chemistry LibreTexts (with USDA figures). chem.libretexts.org

More from Journal

‹ All articles