First Experiment

First Experiment - What are the effects of different types of flour on the height and texture of bread?

Hypothesis

The higher the gluten content of the flour, the larger the increment of height of the bread and the more springy the bread is.

Before Cooking

Who? Wong Tsz Ki Adelaide from group 1

What?

·      Ingredients:

o   Bought in supermarket

o   Flour (strong, plain, cake)

o   Instant yeast

·      Home kitchen

o   Salt

o   Olive oil

o   Water

·      Equipment:

o   Home kitchen

§  Balance, teaspoon and tablespoon for measurement

§  3 bowls

§  Cling film

§  Oven

Where? Home kitchen

When? 17th March 2020 16:00; take measurement before (height) and after baking (height and texture)

Why? To find the best flour to make loaf bread

How?

·      Experiment

o   Follow the recipe and separate the fermented dough into 3 proportion and bake in 3 times

o   3 trails for each kind of flours (9 in total)

·      Result

o   Measure the height of the bread using ruler and take the average height for the result

o   Cut into half and observe the texture of the bread

Variables?

Independent Variable	Dependent Variables	Controlled Variables
Types of flour ·      Strong flour ·      Plain flour ·      Cake flour	Height ·      The increment of the height of the bread (height after baking – height before baking) Texture ·      Air bubbles ·      Soft/ Hard?	·      Amount of other ingredients ·      Brand of other ingredients ·      Baking time and temperature ·      Fermentation time ·      Cooking environment and temperature

While Cooking

The video below recorded the whole cooking process.

Ingredients:

Strong white flour                   500g (plus extra for dusting)

Salt                                          2 teaspoon

Sachet fast-action yeast          7g

Olive oil                                  3 tablespoon

Water                                      300mL

Instructions:

1.     Mix 500g strong white flour, 2 teaspoon salt and 7g sachet of fast-action yeast in a large bowl.

2.     Make a well in the centre of the dough, then add 3 tablespoon olive oil and 300mL water, and mix well. If the dough seems a little stiff, add another 1-2 tablespoon water and mix well.

3.     Tip onto a lightly floured work surface and knead for around 10 mins.

4.     Once the dough is smooth, place it in a lightly oiled bowl and cover with cling film. Leave to rise for 1 hour until doubled in size.

5.     Line a baking tray with baking parchment. Knock back the dough (punch the air out and pull the dough in on itself) then gently mould the dough into a ball.

6.     Place it on the baking parchment to prove for a further hour until doubled in size.

7.     Heat oven to 200.

8.     Dust the loaf with some extra flour.

9.     Bake for 25-30 mins until golden brown and the loaf sounds hollow when tapped underneath. Cool on a wire rack.

After Cooking

Increment in Height

	Strong Flour	Plain Flour	Cake Flour
1	6.5 - 4 = 2.5 cm	5.5 - 3 = 2.5 cm	4 - 2.5 = 1.5 cm
2	7 - 4 = 3 cm	5.5 - 3 = 2.5 cm	4 - 3 = 1 cm
3	7.5 - 4.5 = 2.5 cm	6 - 3.5 = 2.5 cm	4.5 - 2.5 = 2 cm
Average	2.67 cm	2.5 cm	1.5 cm

Texture

Strong Flour

Plain Flour

Cake Flour

	Strong Flour	Plain Flour	Cake Flour
Springiness	Most springy	Moderate springy	Least springy
Size of Holes	Large	Moderate	Small
Softness	Soft	Soft	Hard

Analysis

Increment of height: strong flour > plain flour > cake flour

Springiness: strong flour > plain flour > cake flour

Size of holes: strong flour > plain flour > cake flour

Softness: strong flour = plain flour > cake flour

Reason behind:

Gluten traps air that form holes in the bread, a higher gluten content implying trap more air, thus larger holes are formed. Air expands and rises when heated, giving a larger increment of height of the bread and the springiness.

Correlation:

• Increment of height (DV) is correlated to the types of flour (IV), gluten content of flour in particular
• Springiness, size of holes (DV) are correlated to the types of flour (IV)

Possible Sources of Errors and Suggestions for Improvement:

1. Inconsistent ingredients amount and cooking process -> extra trials starting from raw materials

The ingredients may have slight errors due to measurements. When mixing all the ingredients and make into the dough, the dough was wet and more flour was added to make the dough dry. Due to making bread manually, there are slight errors in controlling the time and ingredients. Extra trails starting from raw materials to have another dough to give a more reliable test.

2.             Measurement of the increment of height -> mold

As there is no fixed room for the dough to expand during baking, the dough can expand in length, width and height. The only measurement of height cannot be the accurate one. The expansion of gases, or the change of volume, to have both height and width fixed in a mold.