Every Cook is a Chemist!

I used to have a poster in my teaching room with the slogan ‘Every Cook is a Chemist’ written in large letters.

I was delighted that the winner of this year’s GBBO – very well done to him – made a comment about food and baking being based on science. I really wish that more people realised this.

I am not talking Bunsen burners and test tubes. I am talking basic chemical elements and how the wonder of nature has put various chemicals elements together to create food and how the changes that cooking and mixing foods into mixtures and baking them creates amazing things using science. I once read in a food article, that a group of university students were investigating the complex chemical changes that happen when making and baking a cake. Their conclusion was that there are a number of very complex chemical changes that occur when making and baking a cake, some too complex to explain easily!!

If you think about pastry – who doesn’t! – the amount of water used is crucial. You need enough water to work with the protein, gluten, so that it can form long enough chains to go with your rolling pin when you roll out. Otherwise it will crack and break because the gluten strands aren’t long enough. This water is then converted to steam in the oven leaving the traditional crumbly short texture as the water isn’t needed any more. If you add too much water, it might make it easier to roll out as it is very stretchy, but too much is left in the pastry after cooking and the pastry is chewy – too many long gluten strands left. 15ml cold water to 50g flour is about right.

Knowing that Gluten is a protein and how it behaves helps in making pastry using gluten free flour for those with an intolerance. I use eggs and a bit of milk, both protein sources, with a similar structure to that in wheat, that will let the pastry behave in the way that it should. Eggs and milk also contain water which will hydrate the pastry and allow it to roll out.

Eggs are brilliant things in cooking. They contain protein – good quality protein that the body can use from a nutritional point of view – and this is used in so many ways in cakes. Proteins coagulate – set – think of the difference between uncooked and cooked scrambled eggs – so any mixture that contains eggs will become firm on heating. The cakes rise because of air beaten in or baking powder in the mixture and the egg protein sets it in the risen shape. Knowing this, you can correct the ‘doming’ that happens in cake. This happens because the proteins in egg sets first around the edges of the cake so that the only place for any more rising is in the middle. Maybe lower the oven temperature or put the cakes on a lower shelf to distribute the heat more evenly. Eggs contain liquid – egg white is basically protein and water – which helps to hydrate the flour, add moisture to the cake and converts to steam in heat to help the rise.

If you don’t eat eggs or have a vegan diet, what can you do? I have used coconut milk as a successful substitute as it has both protein and liquid as does aquafaba (water from the can of chick peas).

I have often said that if you know why ingredients are in mixtures it makes you a better cook and you can put things right if they don’t go according to plan. Cooking and baking are examples of what I call Real Science. Happy Baking.

Till next time

Food Lady

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