It is not usual for me to start an article with a bit of a rant, but this morning I stumbled upon a blog post (from a published author, I might add) trying to explain the difference between these two staple raising agents in baking. After spouting all sorts of nonsense about how each of them work, and suggesting that it might be down to the flavour, I decided that I would get down to writing an explanation of my own. It is something that sometimes comes up in cookery demonstrations, and it is not nearly as complicated as it may seem…
Bicarbonate of Soda
Sodium Bicarbonate (Bicarb) will act as a raising agent by working in two ways. Firstly, in the presence of an acid. Sometimes I will demonstrate how dramatic this reaction can be by placing some Bicarb in a glass and then pouring in a little Vinegar. You can perform this science experiment at home – the result is quite spectacular as the combination sizzles and bubbles away (think of opening a shaken bottle of fizzy drink). The second is in the presence of heat. The two of these factors together is what will help to make any baked good rise once it is placed in the oven. But, here is the important thing to remember – Bicarb always requires the addition of an acid in order to start that chemical reaction. This is why you will find that recipes that call for Bicarb usually have more acidic ingredients. Even cocoa powder (provided it hasn’t been ‘dutched,’ but that is a topic for another day) is slightly acidic and the inclusion of ingredients like buttermilk or yoghurt will also set off this reaction. Sometimes lemon juice or vinegar may be added to the recipe to create the same effect.
TIP: try not to add the bicarb to very hot ingredients as this will make the mixture fizzle before the party has even started. Wait for the oven to gradually work its magic!
The main ingredient in Baking Powder is in fact good ol’ Bicarbonate of Soda. However, it takes care of the need for a slightly acidic environment to begin working by adding it to the mix so you don’t have to. This is achieved by the addition of certain mineral salts. Baking Powder will be used in most batters and mixes that are naturally more alkaline. If you read a tin of Baking Powder it will usually state that it is ‘Double Acting.’ This simply means that the both the acidic salts and the heat of the oven will work together to create a fluffy dish without having to add any additional ingredients. You can even add Baking Powder to dishes like mashed potatoes (a favourite culinary tip from the 70’s) and it will fluff up too.
Why do some recipes call for both?
Sometimes, to get the mix just right both Bicarb and Baking Powder will be added to a recipe. This will usually be an adjustment made according to how acidic the mixture is, where just using one or the other might have not quite worked. It’s about fine-tuning! You can add Bicarb to any dish that calls for Baking Powder, but remember you will have to up the ante by adding something acidic too. It may be far too much of a schlep to even think about becoming so scientific in the kitchen, so my suggestion is just keep both stocked up in the pantry and use as necessary. Easy does it.
Is it still fresh?
If you are concerned that the Bicarb on your shelf may be on its way to becoming the culprit in a baking flop, you can always perform the Bicarb and Vinegar experiment above. If it fails to fizz, it may be time to get a new batch. Baking Powder can be tested by adding a little to plain hot (not boiling) water, again the fizz lets you know you are good to go.
Does Baking Powder need to be ‘Organic’?
There is some suggestion that Baking Powder may be contaminated with aluminium. One theory is that aluminium in the powder will give the end product a metallic taste. The bottom line is that adding too much of either agent to a dish will impart this flavour, but it has nothing to do with ‘heavy metals.’ At the same time, aluminium is toxic for the body, so becoming mindful of contamination may be a step towards better health. Personally, I feel that the quantities are in fact negligible and I feel there are much bigger fish to fry when tackling the subject of metal poisoning (for example, using aluminium pots). But, it may be something to consider if you whip up baked goods on a regular basis. The other factor to consider is that some Baking Powders contain traces of gluten, and sourcing a gluten-free product may be important for those needing to be particularly careful to avoid all potentially harmful products. Thankfully, both aluminium- and gluten-free Baking Powders are easily sourced, or you can simply consider making your own. Here’s how…
Baking Powder Recipe
2 parts Cream of Tartar (available at any supermarket)
1 part Bicarbonate of Soda
Combine and use as normal.
TIP: if you are planning to make this in larger batches and storing, consider adding 1 part Cornstarch (Maizena), or Rice Flour, to the the mix which will prevent your mixture from clumping.
The reason that recipes instruct you to pre-heat the oven is that you want to encourage the mixture to rise and set before any of those bubbles have a chance to dissipate. Leaving your cake out on the counter (and I can’t resist adding…or ‘In the Rain‘) can cause a flop. In addition, you can easily burn the outside by placing your mixture in the oven whilst it is heating up as you will in effect grill your batter as the oven reaches temperature.