The chemistry of baking

As much as I was classically trained as a biochemist, I have this stupid tendency to tweak recipe just to " round  the numbers up". This makes my cooking unpredictable as I cannot guarantee the same taste everytime! While I am waiting for my baking genes to get switched on, I start reading up what to avoid and  actually makes baking work.

The secret of successful cooking all lies in chemistry.

Flour
- Proteins in flour give structure through the network of gluten.
- Lower protein flour creates a more tender texture for cakes and pastries.

Baking powder/yeast
- Blow air into bread
- Fermentation of yeast creates CO2 that balloons the bread up

Eggs
- They glue things together and add moisture.
- Need to be at RT for the chemistry to work!
- Prevent air bubbles from bursting

Fats
- They coat protein in flour to prevent the texture to become too bread-like.
- Thus butter needs to be creamy for the gas to get into the fat, and the fat coats air bubbles.

Sugar and Milk
- Gives moisture, soften proteins
- Sugar carries air into the mixture

Salt
- Gives a more elastic texture by strengthening the gluten network
- Helps enhancing flavours

Creaming (Mixing butter and sugar)
- This process blows air into the dough.

Gentle folding in the flour 
- Prevent from breaking the air bubbles

And finally...
there are rules to follow.

1. The sugar must be equal to or less than the flour (in weight, that is).
2. The eggs and liquids (milk) must equal the flour.
3. The fat must equal the eggs.

Isn't that neat?