What is Hot Sake? 6 Things You Need to Know

by Phoebe Amoroso | LIFESTYLE

© Kikusui Sake Co, Ltd, Hot Sake and *Tsukemono* (Pickles)

Japan’s national drink, sake, also known as nihonshu, is found almost universally in restaurants and izakaya (gastropubs) across the country.

Made only from rice, water and koji mold, fermented for around a month, this seemingly simple concoction transforms into a complex beverage, with flavors ranging from melon, pear and blossom to toasted grain and cereal.

Sake can be served at a range of temperatures. While hot sake was beloved for hundreds of years, in more modern times, it has suffered from a bad reputation. Sake experts argue it’s one of the most misunderstood and maligned drinks. However, thanks to concerted efforts in the industry, consumers are once again starting to warm up to hot sake.

1. What is Hot Sake?

Hot sake, or warmed sake, is known as kanzake (燗酒) in Japanese, or sometimes just okan (お燗). This is simply a term for sake that has been heated above room temperature.

© Kikusui Sake Co, Ltd, Hot Sake Water Bath

There are various theories as to its origins, but hot sake is generally believed to have originated in the Heian period (794-1185), when people started heating the drink in a small kettle over a fire. Over time, hot sake grew in popularity, so much so that by the Edo period (1603-1867), many restaurants had a hot sake specialist called an okanban (お燗番).

The okanban would warm sake using a bain-marie (heated bath) method, cleverly changing the heating style and pace to adjust the flavor of the sake to match customers’ tastes. This was a necessary skill, given there weren’t so many varieties available; it was totally dependent on the okanban to produce a different range of expressions from the sake, and to remember what each customer liked. They were also able to tell the precise temperature of the sake without a thermometer, simply by dipping a finger in the warm water bath.

The practice of employing an okanban has largely died out. This decline followed waning popularity in sake overall. Consumption had been falling since the early 1970s, as young people turned to more modern and exciting alcohol imports. This was because sake had generated a bad reputation as a rough, mass-produced beverage drunk by old men.

A concerted effort in the 1980s to change its image followed, resulting in the development of new styles. Breweries began to produce ginjo (吟醸), sake with fruity and sometimes floral notes made with rice grains polished to at least 60 percent of their original size. Namazake (生酒), unpasteurised sake, known for its fresh and lively character, also began to grow in popularity. Yet many of these new types of sake were ill-suited to heating, while other styles were considered low quality. Interest in hot sake cooled considerably.

Eager to change this perception, kanzake evangelists established the National Kan Sake Award in 2009 to promote the beverage and monitor its quality. Their efforts have also been aided by a growing recognition of the value of non-ginjo types of Japanese sake and younger brewers experimenting with less-polished polished rice, sometimes to just 90 percent of its original size. These trends mean that consumers are no longer giving hot sake the cold shoulder, and more and more establishments offer the option to heat different kinds of sake on their menus.

2. When to Choose Hot Sake Rather than Cold Sake?

Crane Kyoto Ware Sake Set, available at Japan Objects Store

Hot sake was traditionally drunk from September 9 until March 3, in fall and winter. However, during the Edo Period, many people would drink it throughout the year, including during the sticky and humid summer, in the belief that it was good for their internal organs.

Seasonality aside, the type of sake on offer is the most important factor. Sake with more umami and higher acidity tends to open up and mellow when warmed, making it gentler on the palate. If that’s a flavor profile you prefer, hot sake might be for you.

Of course, don’t discount personal preferences; if you’re in the mood for hot sake rather than cold, then go for it.

3. What Types of Sake are Best for Heating?

© Kikusui Sake Co, Ltd, Sake Bottle and Oden

Evangelists argue that most kinds of sake can be heated, albeit that some require more care than others. However, there are some general rules.

Honjozoshu (本醸造酒) is sake made from rice polished to 70 percent or less of its original size, with a limited amount of added brewer’s alcohol. This can give it a lighter texture and smoother flavor, and it can often be heated to 55-60°C without any detrimental impact.

Junmaishu (純米酒) is sake made without any added alcohol, literally “pure rice sake,” but the term is often used to refer to sake made with rice polished to 70 percent or less of its original size. It too can open up with some warming, but it’s recommended to cap the temperature at 45°C.

Yamahai (山廃) and kimoto (生酛) are traditional brewing methods that produce sake with a powerful taste and higher acidity, often with earthy and umami notes. These flavors can mellow and soften with heating, allowing new characteristics to emerge.

Futsushu (普通酒), meaning “regular sake,” is often the cheapest available and partly responsible for sake’s bad prior reputation. This kind of sake benefits from heating, as it helps to mask some of its unpleasant aspects and make it more palatable.

4. What about Ginjo and Daiginjo?

© Xtra Inc, Unsplash, Sake Bottles and Dinner Table

Ginjo and daiginjo sake are normally served chilled to preserve their delicate flavors and aromas. However, it’s not true that they should never be heated, although it’s worth getting a true kanzake pro to handle the heating process and bring out the best of each beverage. Generally, 40°C is recommended to bring out new characteristics without losing the original tone.

5. How to Serve Hot Sake

Bamboo Kyoto Ware Sake Set, available at Japan Objects Store

The best way to heat sake is using a hot water bath or bain-marie method.

The Japan Sake and Shochu Makers Association recommends filling a tokkuri (ceramic flask) or any type of heating vessel until 90 percent full and submerging it two-thirds of the way in warm water. Then you just need to monitor the temperature. If you don’t have a thermometer, cover the top of the vessel with plastic wrap. The sake will expand as it warms, touching the wrap when it reaches around 40°C.

The key point to note is that the material of the vessel affects the speed and distribution of heat. Ceramic vessels absorb heat less quickly compared to metal vessels. Kanzake experts will cleverly adjust the vessel to match the sake to produce different flavor profiles.

If you don’t have the equipment to employ the bain-marie method, then you can microwave sake, as long as you proceed with care. Begin by filling a microwave-safe vessel up to 90 percent with sake. Cover the container with plastic wrap to retain the aroma. Heat around 90ml of sake for 20 seconds if using a 600W microwave, or 15 seconds in a 1000W microwave. Then stir once, cover again and heat for another 15 or 20 seconds to get it to around 40°C. This method isn’t ideal as it lacks control and the heat isn’t evenly distributed, but it’s definitely fast and convenient.

Goma Bizen Ware Sake Set, available at Japan Objects Store

The Goma Bizen Ware Japanese sake set, pictured above, is available at the Japan Objects Store. The rustic ceramic material, reminiscent of goma (sesame seeds), is perfect for heating sake on cold winter evenings. To find out more about serving sake, check out Ochoko: 6 Things to Know About Japanese Sake Cups!

6. What are the Different Temperatures of Hot Sake?

The temperature of a given sake will bring out different flavor profiles. Here are the main kinds:

30°C, hinata-kan (日向燗): hinata means “sunny spot,” so this sake conjures the image of lying in the sun on a summer’s day.
35°C, hitohada-kan (人肌燗): this is body temperature sake, so it feels slightly warm.
40°C, nuru-kan (ぬる燗): derived from the adjective nurui (lukewarm), its aromas are a little richer and flavors a little fuller.

45°C, jo-kan (上燗): jo means “upper,” and this sake takes the heat up a notch. Vapor rises when it’s poured and the aromas become more pronounced.
50°C, atsu-kan (熱燗): this sake has reached the level of atsui, meaning “hot.” The tokkuri and choko (sake cup) are hot to the touch. Atsu-kan sake often tastes dry with a clean finish.

55°C, tobikiri-kan (飛び切り燗):tobikiri means “extremely” or “exceptionally”, as in “very, very hot.” Every sake heated to above 55°C is classed as tobikiri-kan.