Cold night, Drink Japanese Sake to keep you warm.

Japanese sake is primarily made from rice, it's a fermented beverage brewed using a microorganism called koji and yeast. Sake has an alcohol content from 13% to 16% which is much higher than beer and slightly higher than wine.
Interestingly enough, the quality of sake depends on the quality of water used during the brewing process. In Japan, brewers take advantage of the various kinds of natural water to brew their best sake. There are many different varieties of sake, and it can be enjoyed either warm or chilled, depending on the season.

As mentioned, sake is very dependent on the quality of water, different regions produce different flavors, and the flavors can be degraded quickly in the presence of light, air and heat. Therefore, sake is generally not aged for these reasons. In Japan, consumers prefer to drink fresh sake, once opened, it tends to get finished as soon as possible before the taste starts to change.
Having said that, you can store opened sake in the fridge for a short period of time. (2-3 days) The longer you leave it out, the less tasty it is.

Red and Black Sake Set #X41470R

In Japan, sake is served cold, warm or hot, depending on the preference of the drinker, the quality of the sake and the season. From my point of view, it is best served as warm to hot in winter. It's smells nice and you can feel the warmth from the inside out. Sake is one of the few alcoholic beverages that can be consumed hot. I normally pack away the white wine during winter and have sake.

People do serve chilled sake in summer, but for me, a glass of white wine is more preferable in summer.

Anyhow... you can see the picture on the right. Sake is first poured into the ceramic flask and warmed up when you are ready to serve. Serve it in shallow cups. The box is just for packaging and it looks great as a gift.

Just in case you want to know, the flask is called 'tokkuri' and the cups are called 'choko' in Japanese.

The Sake Handbook

Sake A Modern Guide

The Book of Sake:
A Connoisseurs Guide