Home baking recipes often call for leavening agents such as pure Baking Soda, Bicarbonate of Soda, Sodium Bicarbonate, Baking Powder, Cream of Tartar and yeast (a whole long list of various types yeast) and each has it’s own characteristics. And if you’re not confused enough already, they all look alike!
If applied incorrectly, your cakes and cookies may taste like soap and even worse, they may become flat, dense and crumbly (actually I’m not sure if that’s the worse thing, I would prefer a flat cake than a soap-tasting one). I did some homework on leavening agents used in non-bread type baked goods (hence I will not cover Yeast in this post) and I will try to simplify what I understand.
First of all, let us understand the mechanism that takes place during leavening process in baking. When leavening agent is added into batter, a chemical reaction takes place which releases gas/ bubbles into the batter to help make the batter (and the end result) rise and become lighter. The gas or bubble released is Carbon Dioxide (CO2) which creates bubble-like structures in the cake making it light and fluffy. The process to produce CO2 in baking can be done several ways using various leavening agents.
By the way, this entry has taken me a few days to write because as I discover more on Sodium Bicarbonate I’m beginning to learn more on how it is being used to naturally clean vegetables, food, your home and there have even been articles about how it is used in cancer treatment. There is a wealth of articles written on Sodium Bicarb so I will not be covering them here and allow me to dive straight into the topic on how it is used as a leavening agent.
Pure Baking Soda = Bicarbonate of Soda = 100% Sodium Bicarbonate
- When mixed with acidic ingredient will produce CO2 bubbles and will function as a leavening agent. Acidic ingredient in baking are items such as buttermilk, lemon juice, chocolate, and honey.
- The CO2 bubbles will expand further in hot conditions (oven).
- Batter mixed with Sodium Bicarb must be baked immediately or the CO2 bubbles will ‘fizz out’ causing the batter to not rise and become flat.
- Sodium Bicarb cannot be used to substitute Baking Powder because when used on its own and without an acid partner, it will not release CO2 bubbles and will not cause the batter to rise.
Baking powder = Sodium Bicarbonate + Acidifying Agent (Cream of Tartar) + Drying Agent (starch)
- Unlike Baking Soda, you do not need to add any acidic ingredient to release CO2 bubbles.
- It is often used in recipes using neutral tasting ingredients such milk.
- Can be found as:
- Single acting – Activated by moisture and batter must be baked immediately.
- Double acting – React in 2 stages and can stand a while before baking. Some CO2 bubble will be released when Baking Powder is added to dough. The majority of CO2 gas will be released when the temperature of the dough is increased in the oven.
- Gluten Free – Rice flour is used in substitute of the Starch( drying agent)
- The drying agent in Baking Powder absorbs moisture in the powder mixture to prevent the Cream of Tartar from reacting with the Sodium Bicarb before usage.
Cream of Tartar
- Acidic in nature (acid salt)
- It is the by-product (sediment) from wine making process. It is the powder which forms inside the wine barrel during fermentation process.
- It is known as a stabilising agent often used in whipping egg whites to ensure stability and volume. It is also used in sugary desserts to obtain the creamy texture of the sugar by inhibiting formation of sugar crystals.
- When mixed with Sodium Bicarbonate in a batter, the combination will act as a leavening agent by releasing CO2 bubbles into the batter.
- However, the biggest concern about using Cream of Tartar in baking is the fact that it is not a Halal product since it is the by-product of wine fermentation process.
- Vinegar can be used in place of Cream of Tartar for whipping egg whites but it is not recommended as a substitute in baking.
There are several companies in Malaysia which produce Halal cream of tartar as indicated by this website. I can’t find any of these items here (in London) so I will be opting for Sodium Bicarb instead of Baking Powder.
Now you may ask how do you determine which leavening agent to use in a recipe. The key is to look at the ingredients called for by the recipe. If the recipe calls of acidic ingredients (i.e. buttermilk, lemon juice, chocolate, and honey), you may use Sodium Bicarbonate and if the recipe calls for neutral tasting ingredients (i.e. Milk), you can use Baking Powder. You can use several website to determine whether an item is acidic or basic (alkaline). I have been referring to this website as my guidance.
Wow, I didn’t realise this is quite a long entry and this is merely scratching the surface on the topic. I hope this post has helped to clarify the different leavening agents often used in baking. Next time you bake, you will definitely be more aware on the chemistry of leavening and how to control the process. Hmmm, come to think of it, Zu’s birthday is coming up and maybe I should whip up something special although…he’s not exactly a big fan of cakes (unless it’s covered in batter and deep fried, twice!).
Till my next post (hopefully a less dry one).