Science 09 : Let's make some yogurt!

I've tried this before in school. So my class have a yogurt party! But... the real yogurt is very sour and I guarantee you'll have a nice sour face after you eat it. So, to make this you need a :

1. Plain milk
2. A pan
3. Plain yogurt
4. Sterilized Tupperware
5. Sterilized spoon
6. Thermometer
7. Stove

How to make it :

1. Put the plain milk in the pan, boil it until the temperature reaches 50 Celsius.
2. After it reaches 50 Celsius, add 3 spoons of yogurt then turn off the stove then cool down the milk until it reaches 30 Celsius. When waiting, stir the mixed yogurt and milk.
3. After it cools until 30 Celsius, turn of the stove. Then, pour the mixtured yogurt milk into the sterilized Tupperware. (Why sterilized? Because if not too sterilized, other organism that not supposed on the yogurt will grow and the good bacteria that supposed making good yogurts death)
4. Put it in a cool place for 2 or more days.
5. After it's done, you can directly eat it or mix it with fruits, jams, and of course ice cream. If you think to eat it directly, you will taste a deathly sour taste (nah, just kidding. But it is really sour!)

Here's a challenge from me : Try to eat a direct fresh yogurt from the Tupperware. If you can handle it, you are a person with a strong tongue! He...he... nevermind. It's just a joke. By the way, making your own yogurt is't that easy. Last time, my teacher see fungus floating in 2 from 3 yogurt in our Tupperware. So if you still insist, I'm not going to stop you. Wish you luck if you want to make it.

Source : Natasha Setianto