Science Pub raises the issue
For the first time I went along to the 'Science Pub' held at the Venetian Theatre in Hillsboro, OR. The science pub is a public talk that the Oregon Museum of Science and Industry (OMSI) hold to discuss various science type things and topics - that's my technical term, and a couple of weeks ago I went along as they were talking baking. Yep, baking is a science, and these guys had Sue Queisser, Food Scientist and owner of Melarova Baking, in to discuss Lift: The Science and Sometimes Surprising History of Leavening Agents... How could I not go!? I bet you're thinking, what a nerd!!
It was very interesting, sciencey but interesting. I thought I would share some of the info I picked up - for those who haven't fallen asleep at the words science, history and leavening :)
Leavening agents or raising agents are the things we add to our baking to make them rise, they basically react with acidity and H2o (water) to create C02 (Carbon Dioxide) - C02 is the name of the game people, an eruption of bubbles creating the loftiness we desire to our baked goodies. Too much raising agent and your batter will over expand and then collapse, it can also taste a bit soapy from the left over baking soda but too little means you can end up with a flat and dense baking result. Are you still reading? Told you it was sciencey.
Baking Soda/Bicarbonate of Soda/Sodium Bicarbonate all mean the same thing but Baking Powder is something different, although they are both leaveners they are chemically different... still with me?
When you are baking and you have a base such as baking soda in your recipe, the recipe usually calls for an acid for it to react to, such as brown sugar; yogurt; lemon juice; molasses and cream of tarter, to name a few. Baking powder on the other hand has baking soda in it as well as the correct amount of acid it needs, cream of tarter (a dry acid) usually there is corn starch as well to keep the two chemicals from reacting prior to baking. They react with the wet ingredients and baking soda has a second reaction with the heat of the oven. If your recipe calls for both baking soda and baking powder it simply means the recipe needs more rise for the amount of batter - not enough acid in the recipe for the amount of batter and you need more leavening.
But what about self raising flour and plain/all purpose flour?
I know this is the next burning question you'd like to raise ;) Self raising flour has baking powder already added so if you don't have any but your recipe asks for it, never fear a solution is here! You can make your own self raising flour by adding half a teaspoon of baking powder to every 4oz/115g/1C of plain/all purpose flour.
When you start whipping egg whites it denatures or tears open the proteins and incorporates air creating foam and lovely light fluffy whites, you can whip egg whites to 8 - 10 times their volume! It may seem simple, just whip but there is a little science here. Different variables can affect the volume and texture, fist off use a clean and dry metal, glass or ceramic bowl and metal beaters as any trace of oil or moisture can inhibit your eggs from whipping. Egg whites are better whipped from room temperature - although this is not essential just desirable.
Begin by slow whipping the whites to create fine bubbles - aka foam, the foam isn't so stable at this point but the proteins proteins improve their elasticity with the friction which enable them to take on more air, thus more volume when you start to crank the speed of your whipping up. Acid added to the whites at the foam stage helps prevent any over beating - over beating results in egg white collapse catastrophe. As the foam is unstable the acid helps stabilize them so they can reach their full cloudlike potential by keeping the foam subtle and elastic. Cream of tarter is usually used.
If you're making meringues, when you add sugar you should do it bit by bit, spoon by spoon so it has time to dissolve, the whites will collapse if you just dump it in. The sugar helps stabilize the foam structure.
Last but Yeast
Yeast is the raising agent used in baking breads. It is totally different than the other raising agents in that it is a fiving fungus. There are three kinds to use: Fresh - which is alive and very active, it usually only lasts for 1 - 2 weeks in the fridge. Active Dry - which is dormant, dried and coated and needs rehydrating. Rapid Rise - dried faster and is uncoated and is very active needing no hydration.
Yeast needs sugar and oxygen to produce alcoholic fermentation and C02. When making bread when the yeast ferments the sugars available in the flour and or the added sugars the carbon dioxide produced gets trapped in the elastic and stretchy (gluten) dough, as a result you get expanding bread dough - yay!
Are you guys still awake and alive after that 'lecture' in the science of raising ya' baking? I hope so and that you found this interesting, even useful in understanding what's going on in your baking creations.
Any questions, please ask (I am NOT a scientist, repeat, NOT a scientist)