Month: June 2010

Nihonshu-do (日本酒度) or Sake Meter Value (SMV)

This article discusses Nihonshu-do (SMV), Buame, Plato and specific gravity for sake Brewing.

Nihonshu-do also known as SMV is the way we measure the sweetness to dryness level of a sake. The word nihonshu-do itself can be broken down into three words Nihon Shu Do with the English counter parts being Japan Alcohol Degree (as in position on a scale). So Japanese Alcohol is Sake and Degree or Meter Value taken together represent the main metric used to characterize sake. At first glance this measure is relatively simple and this is as it should be for sake aficionados. A -4 SMV value for a sake implies it is quite sweet while a value of +10 would be very dry. Its use in brewing reflects its more complicated nature.

SMV was originally based on the Heavy Baume scale created by a Frenchman in the late 1700s. However, the heavy baume scale is only valid for liquids that are equal or heavier than water and this is not the case for sake. For this reason nihonshu-do has the same slope as the heavy baume scale but is not the same. When nihonshu-do and heavy baume are used to evaluate the degree of sugar in water they directly represent the amount of sugar by weight in the solution. While the baume scale is pretty much obsolete today, similar scales like the Balling, Brix and Plato scales are all attempts to measure the amount of dissolved solids in solution with more accuracy, i.e. the grams of solids in 100 grams of water. However, where Baume was working with a sodium chloride solution Balling, Brix and Plato specifically worked with sucrose solutions. Continue reading “Nihonshu-do (日本酒度) or Sake Meter Value (SMV)”

Final Steps in Sake Brewing

The final steps in the sake brewing process is discussed.

After moromi is complete we have only a few more steps to go in our process. These are: secondary ferment, racking, fining, pasteurization, amelioration and bottling. Conditioning and maturation are also terms for the secondary ferment. For the most part the secondary ferment begins after the sake has been pressed out of the lees. At this stage the sake can be anywhere from milky white to relatively clear. However, in all but unusual cases, more, finer lees will settle to the bottom as the sake completes its ferment and rests.

As the ferment completes, alcohol production ceases but the yeast are still active. During the early stages acetylaldehyde, diacetyl and esters are produced and cleaned up, however the clean up follows production by a good amount of time so when there is no more alcohol to produce there is still a sizable amount of these compounds remaining. At this stage the yeast complete their work and clean up remaining levels. It is also at this time that the sake flavors start to come together for a more integrated taste. Continue reading “Final Steps in Sake Brewing”

Preparing Your Rice for Sake Brewing

This article discusses the process of preparing rice for brewing sake or making koji.

An important step performed several times during the sake brewing process is the preparation of the rice. We prepare rice for the moto, then again for each step of the san-dan-jikomi, the three step addition of rice, koji and water to build up to the moromi or the main fermentation. Another addition is sometimes done new the end of moromi called yodan. The preparation of the rice is the same for each of these additions.

Rice preparation consists of washing, rinsing, soaking, draining, packing, steaming, cooling and finally adding it to the brew. Rice for koji also goes through the same process except rather than adding it to the brew it is inoculated and then incubated. But this will be covered in another article. Let’s cover each of these steps separately. Continue reading “Preparing Your Rice for Sake Brewing”

The Main Ferment – Moromi

Discusses the main fermentation stage of the sake brewing process, moromi.

Once san-dan-jikomi is complete and the final addition has been made we enter into moromi. Moromi starts the day after the final addition, which is tomezoe. It lasts until fermentation is almost complete. This can take anywhere from 2 weeks to about a month.

The time needed for moromi is based on both temperature and koji characteristics. In particular the characteristic diastatic power the koji can muster at the moromi temperature.  The yeast work faster at the low temperatures of moromi than do the koji enzymes.

At the end of the moto the alcohol content was anywhere from about 5% to 10%. With the san-dan-jikomi additions the concentration of alcohol was also cut in the same way as the yeast and acid. However, as some yeast has been reproducing some have been producing alcohol. So by the start of moromi we have regained much of the alcohol concentration we had at the end of the moto. Continue reading “The Main Ferment – Moromi”