What is a Junmai?
As explained on that page, Junmai 純米 (pure rice) is one of the categories of classified Nihonshu (TOKUTEI MEISHOSHU 特定名称酒) to which no pure distilled alcohol was added.
Some sommeliers and sake gurus contrast Junmai with Aruten (contraction of arukorutenkazake アルコール添加酒), that is, sake with added alcohol. As if the sakes were either one or the other. I prefer to contrast Junmai with Honjozo 本醸造, graded sakes to which less than 10% of the weight of the rice in alcohol has been added at the end of brewing.
Just because a sake has no added alcohol doesn’t mean it’s a Junmai.
I will explain more about these so-called Junmai hereafter.
What alcohol is added to Honjozo?
By law, it is pure distilled alcohol of agricultural origin, most often made from cane sugar.
It is inserted at the end of fermentation, before the mandatory pressing. Honjozo is not fortified sake; later water will be poured in to restore the alcohol level of before its addition.
For what purpose?
Adding pure distilled alcohol to the brew creates a shock, killing the yeasts. The fermentation stops.
The alcohol then binds to the hydrophobic fatty acids in the Moromi to better dissolve them; as if to recover the aromatic molecules that we would have otherwise lost in the dregs.
Obviously, the fermentation must be finished before this addition otherwise some sugar will remain unprocessed into alcohol.
Furthermore, the level of certain acids (pyruvic and acetolactic) being still high when the fermentation is still going on, they will be transformed respectively into acetaldehyde (menthol flavour) and diacetyl (butter flavour) by the enzymes still active in the tank.
In short, adding alcohol stops fermentation and dissolves acids in the brew to form esters; which increases the concentration of aromas and flavours in the beverage. Once the yeasts are filtered, the enzymes continue to break down proteins and amino acids to form even more ethyls during the maturing period.
Hence these differences between JUNMAI and HONJOZO:
With regard to JUNMAI,
Usually, umami and rice flavours are more assertive since the amino acids are not esterified by pure distilled alcohol.
They are drier because the yeasts can complete their work during the maturation period.
with regard to HONJOZO,
The esterification of fatty acids enriches the sake with ethylic flavours and fragrances, making it more aromatic.
Honjozo, are normally less expensive; the process allows the brewer to lengthen his sake by adding alcohol and water.
Also, thanks to alcoholic shock, Honjozo generally remain more stable, they preserve longer.
Personally, as I am one of those who take their coffee, black and their yogurt, plain, I prefer the Junmai, which are generally better structured; I love the taste of rice, while the aromas of fruits and herbs sometimes seem incongruous to me.
However, adding alcohol often improves Ginjos by giving them more flavour. This compensates for the lost umami which would have been there if the rice proteins would not have been removed during polishing.
THE FALSE JUNMAI
Let’s return to the subject of the “so-called Junmai” which are neither Junmai nor Aruten.
To be considered Junmai, the Nihonshu must first be a TOKUTEI MEISHOSHU (特定名称酒), that is, a classified Nihonshu.
To do this, it must meet all of the following conditions:
Its rice must be a Shuzokotekimai 酒造好適米 (sake rice recognized by the Japanese tax agency) of first quality (Ittô 一等), of special quality (Tokutô 特等) or of superior special quality (Tokujo 特上);
The weight of Komekoji (米麹 inoculated Koji rice) represents at least 15% of the total weight of the rice used to make the sake;
And that it does not contain any additives.
If the sake does not meet all of these criteria, even if it has no added alcohol, it is still regular sake (Futsushu 普通 酒).
This is the case with several Komedake no sake 米だけの酒 which can be translated as sake made only of rice. Although no distilled alcohol was added to them, they are often only Futsushu (unranked sake). This is because they are either made with rice of inferior quality, or with too little Kojimai, or they contain an additive.
The most commonly used additive is dextrose, a simple fermentable sugar. So, rather than lengthening the sake with alcohol, the brewer lengthen it with water and dextrose which will become alcohol. This shortcut is not dangerous, but induces a tart aftertaste.
Please, note that the classification of Nihonshu by the Japanese tax agency is not that useful to guess the taste of sake or to designate a terroir. It has nothing to do with SAQ pastilles or classifications of wines by AOC.
It is useful for estimating the value of sake. A consumer expects to pay more for a Junmai Daiginjo than for a Futsushu for which a brewer has used cheaper products or easier processes.
The name Komedake no sake 米だけの酒 was first used in 1998 by the Sawanotsuru 沢の鶴 brewery (one of the largest in Japan) which invented a process to remove unwanted fats and proteins from rice in Moromi, without having to polish the grains beforehand. At the time, the Junmai had to have a seimaibuai of 70%, Sawanotsuru imagined this name to indicate that his sakes (not Junmai because the rice is not polished) were not Aruten. The commercial success of Sawanotsuru’s Komedake no sake has prompted other brewers to use this process and the label that still confuses consumers.
The tax agency has since removed the requirement for the Junmai to have a 70% seimaibuai. Thus, brewers who prefer to clean the Moromi of unwanted rice proteins and lipids rather than to proceed by polishing respect the specifications and their Komedake no sake 米だけの酒 can be classified as Junmai.
If for other reasons, the Komedake no sake does not meet the conditions to be classified Junmai, the national taxation agency requires for their marketing in Japan that it be written “this is not a Junmaishu 純米酒ではありません” in a minimal 8 point size (approximately 2.8 mm in height) on the packaging (most of these products are sold in one litre Pure-Pak boxes), while still allowing 米だけの酒 to be marked in bulk characters.