Sake is served at three kinds of temperature.
1. room temperature
The sake is kept at room temperature.
Popular to serve: regular sake (hutsu-shu), gen-shu and nigori-zake.
The sake is kept in the refrigerator.
Popular to serve: premium sake (junmai-shu, giunjo-shu & daiginjo-shu)
I think cold is good for enjoying fragrance.
Premium sake has good fragrance.
The sake is warmed up to around 50 degree-C (120 degree-F).
The way to warm it up
1. microwave (if sake ware has some gold pattern, I do not recommend)
2. use a kettle.
3. put sake ware into hot boiled water.
Popular to serve: regular sake (hutsu-shu)
It is a good way to warm up in the winter season.
I like cold daiginjo-shu.
How about you?