What is Japanese sake kimono (fire-dried sake)? This article explains the meaning of kimono and the advanced kimono-drying process in sake brewing.

When buying sake, have you ever been confused by the terms "nama-shu" (raw sake) or "hi-iri" (fire-dried sake) on the label? Understanding the meaning of "hi-iri" is actually the first step in choosing good sake. Japanese sake "hi-iri" is not simply a sterilization process; it involves a sophisticated technique called "bottle-heated hi-iri," which preserves the fresh taste of sake, similar to nama-shu. Miri Store will guide you through the secrets of sake "hi-iri" from the very beginning, making your selection process easier and helping you find the perfect sake for you!

What does "hiiri" mean in Japanese sake?

To understand the secrets of Japanese sake, one must first understand the meaning of "Hiire," which is actually "pasteurization."

After sake is pressed, yeast and a type of lactic acid bacteria called "Hiochi Bacteria" remain in the liquid. If left untreated, the yeast will continue to ferment and alter the quality of the sake, while the Hiochi Bacteria will cause it to spoil, become cloudy, and develop off-flavors. Therefore, the main purposes of sake pressing are twofold:

1. Kill bacteria: prevent the wine from spoiling and deteriorating.
2. Stop enzyme activity: Stop yeast fermentation, stabilize the quality of the wine, and ensure consistent flavor after leaving the factory.

The temperature for pyruring sake in Japan is usually between 60°C and 65°C, which is a temperature range that can kill bacteria without excessively damaging the delicate aroma of sake.

The difference between raw sake and sake that has been cooked is determined by the number of times it has been cooked.

Japanese sake can be divided into four main categories based on the timing and number of times it is heated, which determines whether it is considered "nama" (raw sake) or "hira-na" (heated sake):

Namazake: Fire 0 times

This sake is completely unprocessed by fire, preserving the activity of the yeast and enzymes. Its flavor is fresh and vibrant, like freshly squeezed, often with a slight carbonation. However, its quality is highly susceptible to temperature changes and must be strictly refrigerated throughout the entire process.

Namachozo (raw wine): simmered once

"Raw-aged wine," as the name suggests, is "aged" in a "raw" state. It is not heated during the low-temperature aging process, and is only heated once, just before bottling and shipping. This method can lock in the fresh and crisp taste that is close to that of raw wine, and also ensure the stability of its circulation in the market after it is shipped.

Namazume (raw sake): simmered once.

In contrast to raw storage, the sake undergoes a first sterilization process immediately after pressing, followed by aging in barrels, and is bottled without further heating (bottled/bottled in a "raw" state). The famous autumn-limited "hiyaoroshi" is an example of this type, and after aging in the summer, its taste is usually more rounded and smooth.

Twice Pasteurized: Toasted twice.

The most standard fire-infused sake production process. It undergoes sterilization twice, once before storage and once before bottling. This is the most common type of sake on the market, with the most stable quality; its aroma and taste are not easily altered by the environment, and some varieties can be stored in a cool, dark place.

The pursuit of ultimate flavor: What is bottle-cooked fire-infused?

In the Japanese technique of kirigami (sake simmering), in addition to the traditional method of using plate heat exchangers or coils for rapid heating, there is also a more expensive and complex advanced technique called "binkan hiire" (bottle kirigami).

Regular fire infusion vs. bottle-fire infusion

• General heat pump (coil/heat exchanger) : The wine is pumped through heated pipelines for sterilization. Although it is highly efficient, the aroma of the wine is easily lost due to the heat during the flow of the wine through the pipelines, and the flavor may be affected by drastic temperature differences.
• Bottle Pasteurization : This is a technique where the wine is first bottled and then heated in a low-temperature water bath. The craftsman places the bottle filled with wine into water and heats it to about 65°C to reach the sterilization temperature. Then, the bottle is immediately placed in ice water or a cold storage room for rapid cooling.
  
  

Advantages of using a bottle to heat the fire

The process of simmering the sake in a hot bottle is considered a high-level technique, mainly because it preserves the "original flavor" of the sake to the greatest extent possible.

1. Locking in aroma: Because it is heated in a sealed or semi-sealed bottle, the fruit aromas of Ginjo-grade wines will not evaporate or be lost.
   
2. Retains microcarbonation: It can retain the trace bubbles produced during fermentation, resulting in a more refreshing taste.
   
3. Prevent oxidation: Reduce the wine's contact with air to keep it fresh.

Many high-quality Junmai Daiginjo or limited-edition kirinjo sakes use the bottle-fired kirinjo method to present a fresh taste like raw sake, while retaining the delicate and mellow flavor of the kirinjo process.

Preservation methods and shelf life of wine cooked over a fire

Although the purpose of flaming is to stabilize the quality of the wine and make it easier to preserve than unflamed wine, it still needs to be stored carefully:

• Generally, wines stored over a fire can be kept in a cool, dark place, avoiding direct sunlight and high temperatures. However, to maintain their best condition, refrigeration is still the best option.
• Bottle-fired wine : Since this type of wine usually retains more of its fresh flavor and delicate aroma, it is recommended to treat it as unpalatable wine and store it in the refrigerator as much as possible.

Once opened, the wine should be consumed within 1 to 2 weeks to enjoy its best flavor.

Miri Store offers a curated selection of Japanese-made fire-roasted sake and raw sake.

Understanding the meaning of "hi-iri" (fire-arrival) in Japanese sake can help you choose the right flavor for you. Whether it's the fresh and vibrant "nama" (unpasteurized) sake, the smooth and stable "hi-iri" sake, or even a premium sake made using the ultimate bottle-heating and "hi-iri" process, the method of "hi-iri" for each sake embodies the wisdom and dedication of the brewer. Next time you taste it, pay more attention to the information on the label and experience the differences in flavor brought about by the process.

Miri Shop is dedicated to sourcing premium sake from all over Japan for Hong Kong's sake lovers, offering everything from seasonal unpasteurized sake to high-grade daiginjo sake that has undergone rigorous firing processes. Browse our website now to purchase our carefully selected Japanese products and experience the ultimate taste of Japan directly from the country.