In winter, when room temperature is ver low, it is better to have yeast, even if it is instant, fermented beforehand.
For 300g flour
Dry (instant yeast): 6g (2t)
Lukewarm water (40c): 100cc (1/2 cup)
Sugar: 3g (1t)
Leave the mixture for 10 to 15 minutes.
Note:
- Too much sugar may destroy the yeast.
- Hot water (water with more than 50 degree centigrade) will kill yeast.