Onsen Tamago DOE - SBR1

Our Recent Egg-Mania

Yesterday, I suddenly craved for onsen tamago, while in the office!! I searched the internet for recipe, and I decided that it's something extremely simple that we can make in the office. So, I forced my lunch mates to go to restaurants near to "chai diam ma" so that I can get myself some eggs.

Though you can easily get the recipe from the internet, please bare in mind that the containers are different, and hence the heat transfer rate will be different. Besides, most of the recipe online said you have to control the temperature. There's no way I can control the water temperature in the office. Hence, to make the "perfect" onsen tamago, you need to do real Design of Experiement (DOE).





Here's my experiment log for Onsen Tamago DOE, Special Build Request #1:

Purpose: To find the combination for "perfect" onsen tamagao using tools available in the office
Material & Apparatus: kettle, bowl, spoon, eggs, cold water
Factors: amount of water, temperature, number of eggs in the water
Method:
1. Fill the kettle with x level of water (following the indicator shown on the kettle) 
2. Boil the water
3. Slowly and carefully place y eggs into the boiled water using spoon.
4. Wait for z minutes.
5. Take the eggs out from the hot water and place into the bowl filled with cold water.
6. Peel and ready to serve. (Anyone wish to share the secret to peel the onsen tamago nicely? This is my biggest headache at this moment)

Experiment 1
x = min level indicated on the kettle ( about 1.5 cm over the top of the eggs)
y = 4
z = 20 minutes
Results: the white is soft and springy but the yolk already too hard for my liking

Experiment 2
x = between min and medium level indicated on the kettle (about 1 inch over the top of the eggs)
y = 2
z = 12 minutes
Results: the white is soft and springy but the yolk still too hard for my liking


Experiment 3
x = between min and medium level indicated on the kettle (about 1 inch over the top of the eggs)
y = 2
z = 8 minutes
Results: runny white

Experiment 4
x = between min and medium level indicated on the kettle (about 1 inch over the top of the eggs)
y = 2
z = 10 minutes
Results: the white is soft and springy but the yolk is slightly cooked

I ran out of eggs after these 4 experiments. Tomorrow, I'm going to run SBR #2 by slightly modifying the method. Instead of directly add the eggs into the boiled water, I'm going to wait for w minutes before putting in the eggs. I need the water temperature to drop to certain level (not measurable) so that I can get runny yolk.

Wish us luck :)