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Alcoholic Beverage Q&A

【Seishu (sake)】

  1. How much rice do we need to make 1.8L of sake?

  2.  On average throughout Japan (2011), approximately 1.80L of junmai-shu (with an alcohol percentage of 18.2) is produced from 1kg of polished rice. Before sake is shipped from a factory, water is added to the original sake to adjust the alcohol level to 15% or thereabouts. Thus, approximately 2.38L of sake with 15% alcohol is made from 1kg of polished rice. Therefore, to make one 1.8L bottle of sake needs 0.77kg of polished rice. When we calculate the amount required unpolished rice, polishing ratio* will have an effect. If the polishing ratio is 77%, 1.8L of sake needs 1kg of unpolished rice.

    Rice polishing ratio = Weight of polished rice/Weight of brown rice (%)
    Daiginjyo-shu is a premium sake made from rice with a polishing ratio of 50% or less

  3. What are the differences between rice for eating and rice for sake?

  4.  The shapes of the rice grains and the specific components of the rice are different. For sake making, specific rice cultivars for sake making, as well as rice cultivars for eating, are used. Rice for sake has less protein and a larger grain size that is adequate for high polishing ratio. There is an opaque white core, called shinpaku, at the center of each a sake rice grain. Rice cultivars for sake making is suitable for high polishing rate, good koji-making, and good enzyme digestion even at low temperature. Thus, these cultivars are used for the production of sake with high flavor and delicacy.

    <See page 3, Sake III, in 'The Alcoholic Drink Story', Volume 15. In Japanese only. English version is preparing.>

  5. Can we make sake using rice that was grown in countries outside of Japan?

  6.  Rice is generally classified into Japonica and Indica. In Japan, we cultivate Japonica rice. However, many many other countries (for example, Thailand) mainly cultivate Indica rice. If you can get Japonica rice from outside Japan, you can make sake using that rice. However, Indica rice is not really suitable for making sake. If you try it, you need to take some special measures in terms of the production processes, such as steaming the rice twice.

  7. What is Kimoto (Yamahai) shubo (seed mash)?

  8.  Shubo is an excellent medium for the growth of yeast that is used to ferment moromi (the fermented mash). In order to prevent contamination of wild yeast and bacteria, the seed mash must be made in a strongly acid environment with lactic acid. Shubo is classified as either kimoto (yamahai type) or sokujo (type the faster moto developing method). The kimoto type utilizes lactic acid bacteria to produce lactic acid. The sokujo type uses lactic acid. The kimoto type subo requires twice the time to as the sokujo type. Yamahian moto, a kind of kimoto shubo, means that Yamaoroshi practice in traditional Kimoto making is abolished.

    <See page 3, Sake II, in 'The Alcoholic Drink Story,' Volume 10. In Japanese only. English version is preparing.>

  9. What is the purpose to use jozo-alcohol?

  10.  The reasons for adding jozo-alcohol are:

    (1)To extract the sake flavor that remains in the sake cake.
    (2)To make the sake taste dry and crisp.
    (3)To increase the percentage of alcohol, which prevents the putrefaction of the sake by lactic-acid bacteria.
    (4)To control the taste of sake

    <See page 3, Sake III, in 'The Alcoholic Drink Story,' Volume 15. In Japanese only. English version is preparing.>

  11. What does hi-ire mean?

  12.  Hi-ire means to heat the sake up to around 65℃. Sake is heated to prevent re-fermentation by yeast, to kill the lactic-acid bacteria that sour sake, and to inactivate the enzymes from koji and yeast. Hi-ire is also applied to some wines and beers. It is called "pasteurization". The hi-ire process for sake is believed to date from the Muromachi era (1333-1573).

  13. What is namazake?

  14.  Japanese sake is normally subjected to hi-ire (pateurization) twice (once when stored and once before shipment). However, namazake is not heated at all. Therefore, namazake has a fresher flavor. The quality of namazake changes depending on the storage condition. Because namazake contains many kinds of enzymes, which causes oxidation, hydrolyzation of starch, etc., namazake is unstable compared with standard sake. Store the namazake in a cool and dark place.

  15. What is nigorizake?

  16.  Japanese sake is produced by pressing the moromi mash in a cloth bag, to separate the sake from the sake cake. If the bag made of a fine mesh, such as a woven cotton or artificial textile, most of the cake* will be removed. On the contrary, if the bag is made of a coarse cloth or a filter with big holes, a lot of the sediment remains in the sake. Nigorizake contains a lot of sediment because it is filtered through a coarse mesh bag or filter. Normally, nigorizake is not subjected to the hi-ire process, so its quality is changeable and it has a short shelf life. Some nigorizake was produced through hi-ire, and has a longer shelf-life.
    Sake sediment consist of rice material, rice koji, dissolved materials, and yeast.

  17. How can I understand the terms dry and sweet as applied to sake?

  18.  Whether sake is sweet or dry mostly depends the balance of sugar and acid in the sake. That is, if different sakes have the same sugar content, sake with a higher acid level will not taste sweet. On the other hand, sake with a lower acid level will taste sweet. For example, ginjyo-shu might be considered to be dry because it contains little sugar. However, some ginjyo-shu tastes sweet because it has a low acid level. In addition, the flavor components in sake and smoothness affect sweet/dry taste of sake.

  19. If sake is aged, does it become vinegar?

  20.  Vinegar is made by acetic acid bacteria, which convert alcohol to acetic acid. The acetic acid bacteria cannot grow in a liquid that contains more than 10% alcohol. Since sake normally has 15% alcohol, it will not become vinegar after being aged.

National Research Institute of Brewing