First Experiment (Cathy)

Name: Tsang Tung Yee, Cathy                             UID: 3035690517

Research question: How does the temperature of egg white affect the fluffiness of souffle?

Before cooking:

1. What?
1.1 What ingredients and equipment need?

Ingredients: Butter, sugar, milk, eggs, cake flour (from left to right)

Equipment:
- electronic balance, oven, ramekins, electric mixer (from left to right):

- frying pan, bowls, cups (from left to right in the back)
  sieve, plastic spatula, knife, ruler (from left to right in the front)

- Cooking pot, kitchen thermometer, double lock bag (from left to right) (these are the equipment used for making the water bath for egg white)

-brush (for greasing and coating the ramekins)

1.2 What is the hypothesis?

My hypothesis is that ‘the height of souffle increases as temperature increase, however, after optimal temperature is reached, the height of souffle decrease when the temperature further increase’. This hypothesis is based on the websites, which suggest that egg whites reach greater volume (and hence fluffier) when they are beaten at room temperature than refrigerated temperature. Another website further suggest that high temperature is unfavorable for making fluffy souffle. Since websites are commonly regarded as a less trustable source, this experiment aims at investigating whether there is a valid link between temperature of egg white and the fluffiness of souffle.

The independent variable is the temperature of the egg white before whisking. As temperature increase, surface tension decrease, this low air-to-liquid interfacial tension facilitates the attachment of hydrophilic part of protein to water and the hydrophobic part to air, result in the formation of air bubbles (foam), which expands upon baking and make the souffle rise, thus causing the increase in height of the souffle. In addition, it is suggested that under high temperature, too many bonds will be formed between egg white protein molecules, which reduces the formation of air bubble and hence causing a decrease in souffles’ height. Therefore, it is shown that temperature of the egg white affects the height of the souffles, which is the dependent variable of this experiment. The height of the souffle is used as a quantifiable indicator of the fluffiness of souffle. This is because the more the air bubble inside the souffles, the greater the increase in souffles’ height during thermal expansion under baking, which contributes to souffles fluffiness.

For the controlled variables, the amount and brand of all the ingredients, the time and strength for same heating and mixing process in different sets, the way in greasing and coating the ramekins, the amount of souffle mixture added in each ramekin, the positions in which ramekins are put in the oven and the immediate measurement of the souffles’ height  have to remain identical.

Independent variable, dependent variable and controlled variables summarized in a table:

Independent variable	Dependent variable	Controlled variables
- temperature in which the egg white is stored before whisking. (0 °C, 10 °C, 20 °C, 30 °C, 40 °C, 50 °C, 60 °C, 70 °C and 80 °C)	- the height of the souffle, which implies the fluffiness of the souffle.	- brand of all ingredients (butter, sugar, milk, egg and cake flour). - volume and the amount of all ingredients (butter, sugar, milk, egg and cake flour). - speed of whisking the egg white by electric mixer. - time of whisking the egg white by electric mixer. - the length of baking time. - the temperature of the oven used. - the fire temperature of the stove used. - time for mixing the cake flour in the stove. - time for mixing the egg yolk mixture. - time for mixing the egg yolk and egg white mixture. - the volume of souffle mixture in each ramekin. - the amount of butter used for greasing each ramekin. - the amount of sugar used for coating each ramekin. - the length of time in which the egg white is stored under different temperature. - the position in which the ramekins are put in the oven. - the time to measure the height of souffle after baking is completed.

2. Who?

2.1 Who do the shopping, cooking?

I (Cathy from group 17) will do the shopping, pay for the ingredients needed and cook all those nine sets of souffle.

2.2 Who do the measurement?

I will take part in the measurement to reduce measurement error that due to inconsistent measurement methods that may arise if I ask my mum for help. I will do the measurement quickly as the souffle will quickly deflate once it is removed from the hot oven. 

3. Where?
3.1 Where to obtain ingredients, equipment and tools?

Ingredients are bought in local supermarket while equipment and tools are bought in both bakery store and JHC.

 3.2 Where to cook?

I cook in the kitchen at my home.

4. When? _ When to start cooking?

Cooking starts at the 20^th March, 2020.

5. Why? _ Why is this investigation important?

This investigation is important as it aims at finding the best temperature of the egg white for making the fluffiest (highest) souffle. This best temperature obtained is craved by people as this increases their opportunities for baking fluffy souffles successfully.

6. How?

In each set, 4 souffles are baked. In total, there are nine sets of souffle, in which the temperature of the egg white (before whisking) range from 0°C to 80°C at every 10°C interval, that is, (0°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C and 80°C). Once baking is completed, measure the height of souffle quickly by a ruler and record them. If the height of souffles are not within the range of plus or minus 0.5 cm, it will be eliminated and viewed as error. Then, calculate the average height of each set of souffle. Eventually, a graph that shows ‘How does the temperature of egg white (x-axis) affect the height of souffle (y-axis)?’ will be shown to show under which temperature of the egg white will the highest souffle be produced.

 

While cooking:

Step 1: Separate the egg yolks from egg white.

Step 2: Pour the egg white into a double lock bag and then put it into a water bath. Photo graph below shows the water bath of 20°C.

       

Step 3: Use the electronic balance to precisely measure the weight of different ingredients.

    

Step 4: Brush butter and sugar for greasing and coating the ramekins respectively.

Step 5: Bring milk, sugar and butter to simmer for 2 minutes.

                                         

Step 6: Sift in cake flour to the mixture. Blend while sifting in the flour. Stop blending when no cake flour granule remains.

Step 7: Add egg yolk to the mixture and mix it for 1 minute.

 

Step 8: When the egg white reach thermal equilibrium with its surrounding water, pour the egg white into another bowl and add sugar into it.

The photo below shows the egg white in different temperature:

[first column:      0°C, 10°C, 20°C from left to right]

[second column: 30°C, 40°C, 50°C from left to right]

[third column:     60°C, 70°C, 80°C from left to right]

Step 9: Whisk the egg white for 3 minutes.

 

Step 10: Mix 1/3 of the egg white mixture to the egg yolk mixture.

Step 11: Pour the above egg yolk and egg white mixture and mix them for 1.5 minutes.

Step 12: By using an electronic balance, add 20g of mixture into each ramekin.

Step 13: Bake the souffle in the oven at 180°C for 16 minutes.

 Step 14: Repeat the whole experiment and change only the temperature of the water bath in step 2. 

Video clips showing the making of one set of experiment:

 

(I am sorry for the instability of the videoes)

After cooking:

The height of the souffles are measured by using a ruler once the oven dings. The measured height is then typed on the computer. 

 

Temperature of the egg white  (before whisking)	The appearance of the souffle  (after baking for 16 minutes)	Measurement method
0°C		Ruler outside the ramekins
10°C		Ruler outside the ramekins
20°C		Ruler outside the ramekins
30°C		Ruler outside the ramekins
40°C		Ruler outside the ramekins
50°C		Ruler outside the ramekins
60°C		Ruler inside the ramekins
70°C		Ruler inside the ramekins
80°C		Ruler inside the ramekins

Preliminary trial result

The temperature of egg white before whisking (°C) [INDEPENDENT variable]	Height of the souffles (cm) [DEPENDENT variable]	Average height of the souffles (cm)
0°C	5.8, 5.8, 6.0, 6.2	5.950
10°C	5.8, 5.8, 6.1, 6.2	5.975
20°C	3.5, 3.5, 3.5, 3.8 (original trial) 6.1, 6.2, 6.5, 6.5 (repeated one)	6.325 (repeated one)
30°C	5.0, 5.1, 5.6, 5.8 (original trial) 6.3, 6.5, 6.5, 6.7 (repeated one)	6.500 (repeated one)
40°C	7.3, 7.3, 7.4, 7.6	7.400
50°C	4.9, 5.0, 5.1, 5.3	5.075
60°C	1.4, 1.8, 1.8, 1.8	1.700
70°C	0.8, 0.9, 0.9, 1.0	0.900
80°C	0.7, 0.8, 0.9, 0.9	0.825

Visualization of trial result (graph titled "Effect of temperature of egg white on the average height of souffles")

Correlation between independent variable (x-axis) and dependent variable (y-axis):

The experimental results fulfill my hypothesis of ‘the height of souffle increases as temperature increase, however, after optimal temperature is reached, the height of souffle decrease when the temperature further increase’. As shown in the graph above, when temperature of egg white increase from 0°C to 40°C, the average height of souffles increases from around 6cm to over 7cm, a positive correlation between temperature of egg white and average height of souffles is shown. However, as temperature of egg white increases from 40°C to 80°C, the average height of souffles decrease drastically from over 7cm to below 1cm, a negative correlation is shown.From the graph, 40°C seems to be the temperature in which the higher souffle is produced. However, a further experiment that are conducted with smaller temperature interval (for example,1°C between the temperature rang of 20°C and 40°C) should be used to determine the best temperature more accurately.

Problems identified and its corresponding improvements:

1. The temperature of water bath is inconsistent as there is constant heat loss to the surrounding. As a result, I have to heat it again and again to maintain the experimental temperature. Although I have use thermometer to measure the temperature of egg white before whisking, these interruption may still affect the accuracy of the result. For further improvement, a larger volume of water can be used for the water bath and insulators like plastic box can be used for holding the water bath.

2. The measurement of souffles' height using a ruler is fine if the souffle rises above the ramekin. However, for temperature like 80°C, the souffle stay inside the souffle and I can only 'dip' the ruler to measure the height, measurement error may arise. Therefore, to improve it, I may use a bamboo stick to measure the height of souffle and record it by a marker, such that I can maintain a consistent measurement method throughout the entire experiment.

3. During the recording of videos (by my friend) and short clips (by myself), errors occur as I am nervous and distracted. As a result, errors occur, for example, in the video, I accidentally forget to add sugar into the egg white and pour some souffle mixture out of the ramekins. As a result, the experiments set of 20°C and 30°C has been repeated to find the 'normal' average height.

Reference:

https://www.preparedfoods.com/articles/112210-creating-egg-white-foams