After coming back home, I miss the fresh yogurt. I then searched for the recipe on the net, surprisingly it's so easy! The only thing I needed to buy was a food thermometer.
I reused a spaghetti sauce glass bottle for measuring the amount of milk I need and to store my yogurt. I do not have a heating pad, I wrapped the bottle of warm milk + yogurt starter with towels, then put inside a food warmer bag and left it at a corner in my kitchen.
I didn't want it to be too sour, so I left it for about 9 hours (overnight). I woke up in the morning, sliced some strawberries, mixed it in the yogurt, and placed it in the fridge.
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Homemade yogurt is not as thick as the commercial ones. It tastes great with the appropriate sourness yet feels so fresh especially to eat it with (lots of) fresh fruits.