ITS PASTEURIZATION 火入れ
It is not by adding sulphites that the Japanese ensure the preservation of their sakés.
Saké is traditionally brewed during the cold winter months. Especially with the craft brewers I do business with. Starting the brewing season at the end of October, after the rice harvest, allows them to keep the community active; the artisans of Kura are often the farmers who work in the culture of rice. ⠀
In cold weather, there are fewer contaminants in the air and wild microorganisms are kept dormant.
Also, saké breweries apply strict hygiene. When I visit them during the winter, they always worry that I have eaten food prepared with microorganisms in the 24 hours before the visit—especially natto (fermented soy beans), but also yogurt and Calpis.
At the end of the brewing process, the fermentation is terminated by pasteurization. The saké is heated briefly to around 65 ° C (to be immediately cooled), either by passing it through pipes submerged in hot water or by immersing the bottles in scalding water. This is hot enough to kill microorganisms, denature enzymes and stop any additional activity that would alter the character of the saké over time.
For its preservation, saké is therefore pasteurized.
Oh yes! Like milk. And twice rather than once.
The first time after filtering (before maturation in the tank) and a second time, during bottling.
After fermentation, the sake circulates for a brief moment through a coil bathed in a vat of hot water. Enzymes and microorganisms undergo a thermal shock which destroys them.
Pasteurization is part of the standard saké making process - in fact, the standard is double pasteurization. A first pasteurization after filtering, when it is placed in the tank for maturation (two to six months), and a second, at the bottling.
In Japanese, this process is called 火入れ (hiire), literally, it is firing.
In the 19th century, Louis Pasteur, who after studies on fermentation, developed a method of preserving fermentable solutions which consisted of heating them to 65 ° C for a short time. In Japan, one proceeds to the hiire since the Heian era (period which extends between the years 794 and 1185 of the Christian calendar).
Pasteurization deactivates enzymes and kills bacteria (especially those that produce lactic acid) and yeast. Stopping microbial and enzymatic activity stabilizes saké. It is fixed; its maturation is slowed down and it will keep it as it is longer, even without refrigeration.
Of course, heating saké to a temperature high enough to denature the protein can alter its flavour.
This is why some brewers sell unpasteurized saké.
NAMASHU or NAMAZAKE 生酒 are sakés that have not undergone any pasteurization. They can also be called simply NAMA (生 or なま), NAMANAMA (生生) or HONNAMA (本生).
NAMA 生 can be translated as alive or raw.
Unpasteurized saké is therefore alive and, like yogurt, it should be kept cool at all times.
The characters 要冷蔵 (YOREIZO) usually appear on the label and indicate the need for refrigerated storage.
Namazake develops a complexity of taste over time.
It has a particular flavour profile; herbaceous and spicy, and can also be slightly sparkling due to the continuous production of gas by the still active yeast in the bottle.
Some people don't like it, but those who like, it love it! It's a matter of taste.
Often, it has a cloudy appearance and requires a careful cool storage without light, otherwise it can quickly develop earthy flavours and unpleasant mushroom or mouldy odours.
The obligation to keep them in the refrigerator at all times means that there are few namazakes available outside Japan. During export, the multiplication of intermediaries and the lengthened period between their release from Kura and their tasting increase the risk of degradation.
The namazakes found here have very often gone wrong. It is because the warehouses and shelves of the SAQ are not refrigerated, and neither are the wine cellars of restaurants.
Fortunately for us, between the standard of two pasteurizations and the complete absence of Hiire, there are compromises which allow to obtain a satisfactory conservation.
Two compromises consist in using only one of the two pasteurizations.
The NAMACHOZO 生貯蔵
NAMACHOZO 生 貯 蔵 are pasteurized only when they are bottled. It is the first of two styles of semi-nama. Since they are still alive during the 2 to 6 months maturation in tanks, they develop a rich umami with a grassy profile. Because the fermentation is not stopped and continues during the months of mellowing, NAMACHOZO 生貯蔵 become very dry, fermenting all the sugar.
NAMACHOZOSHU 生貯蔵酒 generally has aromas and flavours reminiscent of NAMAZAKE.
For our greatest pleasure, because it was pasteurized during bottling, it tolerates travel and storage at room temperature better than NAMAZAKE.
The NAMAZUMESHU 生詰酒
The second semi-nama style is NAMAZUMESHU 生詰酒. These sakés are pasteurized just before their maturation in the vat, but not when they are bottled.
A brewer can skip this second pasteurization and bottle the once pasteurized saké directly, and avoid spoiling the brew by cooking it a second time.
Names of sake according to their pasteurization
First hiire 火入れ
2nd hiire 火入れ
Morita Shobé's Komaizumi Magokoro Daiginjo NamaChozo 駒泉 真心 大吟醸 生 貯蔵, pasteurized only before bottling, matured raw, which gives it a complexity of taste.
It is dry, but very silky. It offers the fruity aromas of Daiginjo and the umami of lactic acid.
It is recommended to serve it chilled.
Other processes make it easier to store namazakes 生酒 without refrigeration, such as microfiltration or ultrafiltration. Microfiltration through plates with fractional micron holes will remove microorganisms and stop the brewing process, without cooking, as it is done with Purefiltre milk which is not pasteurized. It is also a method used by some winemakers to reduce the use of sulfites.
Another option is to package the sake under a protective atmosphere (by replacing the oxygen in the container with nitrogen) in an opaque container that will also shade it from damaging light.
The alcohol added at the end of brewing in the case of Honjozo helps with preservation. It has the effect, among other things, of stopping fermentation. Namas that are not Junmai would be more stable.
Akita no Osagekko Nama Junmai Genshu Muchosei
秋田 の おさげっこ生純米原酒 無調整 from Asamai Shuzo is a delicious Junmai (therefore without adding alcohol) without pouring in water and without pasteurization!
Its dark glass bottle containing no oxygen allows you to preserve and taste the best of its Nama character.
PLEASE SERVE CHILLED
Regardless of the type of nama, their peppery and herbal flavours are best appreciated when served chilled or even cold. They can even be poured over ice.