Harri Deacon and Keely Dunn of Balclutha Primary School asks :-
When making bread, why do we need to knead the dough and why is bread baked in such a hot oven?
Nigel Larsen, a food chemist, and Ian Waters, a baking technologist, of Crop and Food Research, responded.
This question asks about two of the special ‘secrets’ of making bread. First - mixing bread dough makes stuff called gluten. Gluten is kind of rubbery, or elastic. Kneading dough works the gluten so it makes bigger loaves of bread with a nice crumb texture- good for buttering!
The second bit is about yeast. We add yeast so it can grow and produce bubbles of carbon dioxide gas in the dough. It is the gas bubbles in the dough expanding that make dough rise. Kneading dough breaks the gas bubbles into smaller ones so our bread won’t have large holes. You don’t want all the butter going through holes in your toast!
We can mix and knead a small dough by hand but it is hard work, so bakers use special mixing machines.
There are several reasons why a bread oven needs to be so hot. Firstly, it makes the dough rise fast to the size of loaf we want. Then the heat kills off the yeast to stop it from producing more gas.
Secondly, the heat melts some of the starch and set the dough. First it sets the outside dough and makes the crust. Then it sets the crumb structure inside the bread. The crunchy crust and the soft crumb inside is part of what makes bread so nice to eat.
Finally, the heat browns the crust, making it tasty and producing the delicious smell of fresh bread. It is possible to make bread without a brown crust, but it doesn’t taste or smell very nice.
If you want to read more about baking bread and the baking industry in New Zealand, check out the website at www.bakeinfo.co.nz.