As temperatures are getting cooler here in Europe, the leaves are changing colour and we all spend more time indoors. What better time to have look at warm sake!

Hot sake = bad sake?

Many people have the idea that all hot sake is bad sake and that only low-quality sake is heated, which masks the bad taste. Unfortunately, this myth is often confirmed by restaurants that serve generic, sharp-tasting hot “sake”; mostly cheaply mass-produced outside of Japan.

In fact, warm sake (kanzake 燗酒) can be a joy to drink, especially with food! Heating a sake brings out new flavours and aromas, which are perceived differently at varying temperatures. A sake that you already like to drink chilled might take on a different character when heated.

Your perception of the aroma and taste of a sake changes with the temperature. Sweetness and umami will seem stronger, while any bitterness is subdued. Generally, the heavier, richer aromas are emphasised by heat, while lighter aromas (anything floral, fresh and fruity) don’t fare as well. But be careful, as the alcohol will also become more noticeable as the temperature rises.

What sake can be warmed?

Umami-rich sakes made with less-polished rice such as junmai and honjozo and even regular sake (futsu-shu) are very well suited to be drunk warm. Especially Junmai brewed with the traditional yamahai or kimoto method (a time- and labour-intensive way of preparing the yeast starter that results in funky, earthy and more complex aromas) is often even better when warm. Aged sake (ko-shu) with its savoury aromas can also be an excellent choice if you want to try warm sake. Cloudy (nigori) sake can go both ways— the category is so diverse, you’ll need to experiment.

The more delicate styles like ginjo and daiginjo are usually best when lightly chilled, although a rich, sweet junmai ginjo made in a modern style, especially when unfiltered (muroka) and undiluted (genshu), can be even more complex at room temperature. The same goes for sparkling sake; the bubbles would disappear when it’s heated and then what’s the point?

Turn up the heat

As mentioned, warm sake can be enjoyed at a wide range of temperatures. The different temperature ranges all have their own names in Japanese, but if you want to shine at your next visit to a Japanese sake bar you only need to remember atsu-kan (hot, 50–55°C), nuru-kan (warm, 40–45°C), and jo-on (room temperature, anything between 15–30°C).

It’s impossible to set up any rules which sake is best at what temperature. Even just 5˚C can make a big difference. But half the fun is experimenting and finding the sweet spot for your favourite sake.

How to heat sake

The easiest way to heat sake is in a water bath. Heat some water in a pot on the stove or in an electric kettle. Turn off the heat and pour some sake in a heat-tolerant beaker or a tokkuri if you have one and place it in the hot water until the sake reaches the desired temperature. There should be enough water in the pot to reach at least half way up your sake vessel. Use a thermometer to check the temperature and remember to give the sake a gentle stir once in a while so it warms evenly. Depending on the temperature, it should take somewhere between 2–5 minutes.

Be careful not to let the sake go over 65˚C, or the alcohol will begin to evaporate. To preserve the aromas, it’s a good idea to wrap the top of your carafe with tinfoil.

In Japan, sake bars also use a water bath for heating their sake, but of course they have a more professional setup called kansuke that is temperature controlled and can hold multiple pitchers at the same time. Lidded pitchers made from tin or other metal are used because conduct the heat very well. Traditionally, any serious bar would have a person responsible only for heating sake, but as fruity ginjo-style sake, which is best drunk chilled, became more popular this profession faded away.