Video transcript: bread making
Inside us is a framework of bones which gives shape and support to our body which we call our skeleton…
…and in all these goods there is a type of skeleton which we called ‘denatured proteins’ which gives structural support too.
This structural support mainly comes from the protein gluten, which is found in wheat flour.
What is wheat flour?
(Shot at Otterton Mill)
Flour is made by grinding and crushing grains of wheat.
Flour can be made from many different cereals, but in the U.K. wheatflour is the most common.
Some old flour mills like this one, use water power to crush grains of wheat to make the flour.
The process you can see is making wholewheat flour, which is also called wholemeal flour.
Wholemeal flour is made into white flour by rolling and sieving out the bran and wheatgerm which leaves the inside of the wheatgrain called the endosperm.
Wheatflour grown in the UK is not very high in gluten, so it is sometimes blended with ‘harder’ wheats from other countries,
Science activity: great globs of gluten
Ok we’re going to make great globs of gluten here, we’re going to make a soft elastic dough out of 3 different types of flour, we’re going to use a plain flour, a strong bread flour and a wholewheat flour and we’re going to use 50 grams of each.
Make the globules
Ball 1: plain flour
Ball 2: strong bread flour
Ball 3: wholewheat flour
Add enough water to form a soft dough ball and knead for 5 minutes until the dough becomes smooth and elastic.
So this can be done on a work surface or if you prefer in a bowl.
Knead all of the flours for the same amount of time ………some flours will form better balls than others.
The wholewheat flour may require a little bit extra water in it as the bran inside it will soak up a little more of that water.
What happens when we knead dough?
Inside all these wheat flours there are 2 proteins in the wheat kernel called gliadin and glutenin.
When we carry on kneading those 2 proteins combine together to form gluten.
So by the end of the kneading you should end up with a nice clean board and nice clean hands.
So we’ve finished all 3 of the balls – and we’re now going to let them rest and relax for 5–10 minutes.
10 minutes later
Now to find out which of our great globules of gluten has got the most gluten in it.
Washing away the starch
To do this we’re going to wash away the starchy carbohydrate and leave behind the gluten that we formed earlier in kneading.
To wash away the starch wrap each ball in a muslin cloth and rinse under the tap for about 20 minutes.
Time to weigh the gluten globules
From the plain flour we have 15g of gluten from 50g of flour.
From the strong bread flour we have 29g of gluten from the 50g of flour.
From the wholewheat flour we have 15g of gluten from 50g of flour.
Here you can see that the bran and wheatgerm, these are part of the wholemeal flour, but do not form part of the gluten structure.
You can see from these samples that strong plain flour has the most gluten, so this flour will make the best bread.
Properties of dough
So with our concentrated balls of gluten we can also have a quick look at the properties.
We can see that they are plastic which means that they can change their shape, like this wonderful ball of putty & they’re elastic which means that when we stretch them like this balloon they can stretch and return to their original shape.
These plastic & elastic qualities of wheat dough allow it to trap gas (such as carbon dioxide made by yeast) and expand, which helps breads and other baked goods rise to become light and fluffy!
So having seen the properties of all 3 gluten globules we’re now going to see what happens if we actually bake them in the oven.
Bake for about 10 minutes at 200°C
After baking the gluten globules you can see how the different types of flour & levels of gluten result in different loaves of bread.
The plain flour does not contain enough gluten for successful bread making. You can see that the gluten ball extracted from the flour is small compared to the strong plain flour. The loaf made from this flour does not have as much volume and the loaf’s structure is softer and weaker.
The strong plain flour has more gluten, it produces a loaf that has a firmer structure and is more crusty. The bread holds together better when it is sliced and has a firmer, chewier texture which is what we want in successful bread.
The wholemeal flour has less gluten than the strong plain flour. The gluten present also has the bran and wheat germ mixed in with it which also weakens its structure. The loaf it makes will have less volume than the strong plain flour. (But remember for healthy eating, we all try to eat more whole grains and wholemeal bread provides this).
So the best flour for bread making was the strong plain flour.
- Most bread sold in the UK is made from wheat flour
- Gluten is the protein in flour which makes the dough stretchy and gives the bread its texture
- Wheat flour grown in the UK is not very high in gluten, so is sometimes blended with “harder wheats” from other countries
- Bread dough must be kneaded for at least 5 minutes to develop the gluten to make the dough stretchy
- The gluten in flour can be extracted by washing away the starch
- Gluten balls are stretchy like bubble gum – they are balls of protein!
- The higher gluten flours which are also known as bread flours give the bread a good crust and a stronger lest crumbly texture. The best flours for bread making are strong flours high in gluten.