Month: April 2010

Koji What?

This article discusses what koji is and what it contributes to sake.

The most mysterious ingredient use to make sake is koji. What is it? Why is it so important? What does it contribute to sake? Well, these are all important questions we will address here. Koji is a general term that is almost always used as a specific term by those talking about sake. In the general case koji is some kind of substrate with some kind of mold growing on it. How’s that for a technical description. Koji used for making sake is, in most cases, yellow koji consisting of  Aspergillus Oryzae growing on milled rice.

Yellow koji is also used for making Shochu, a distilled beverage, but has been mostly replaced by other forms of mold and substrate. The two most common molds now used for koji in the production of shochu are Aspergillus Kawachi (white) and Aspergillus Awamori (black). In the general case the substrates also very quite a bit. Substrates of buckwheat, sweet potato, barley and rice are common. Rice is always the substrate used for sake. Continue reading “Koji What?”

More Sake Yeast

This article contains information on the yeasts that the Japanese Central Brewers Union collects and distributes.

Last week I wrote about sake yeast but the post got to be longer than I intended so I cut it short. I left off a little of the more commonly mentioned information about the yeast strains collected and distributed by the Central Brewers Union.

You may recall from the last post that back in the early 1900s the Central Brewers Union in Japan started collecting pure strains from particularly good batches of sake. The Central Brewers Union then made these pure strains available to all breweries. These pure strains where given numeric designations. So far there are from #1 to #16 and the low foaming strains. Many breweries now use these yeast strains but many also use of private strains. Continue reading “More Sake Yeast”

Sake Yeasts

Discusses yeast, sake yeast and what yeast need to do a good job fermenting.

Yeast: a single cell fungus whose activities have been known to man for far longer than we have known about yeast itself. We have evidence of yeast being used as far back as four thousand years ago in Egypt. They used yeast for both baking and brewing. Wine was also present in this period.

In 1857 Louis Pasteur proved that fermentation was the results of living yeast rather than a chemical reaction. In this work, Pasteur showed that as oxygen is added the growth of the cell count increases and fermentation slows. Not only did this show the significant of yeast but also its two distinct modes of operation: the aerobic and the anaerobic. In the aerobic mode, yeast reproduce by budding, a process of a child cell being created and split off from the parent cell. The anaerobic mode proceeds with little to no growth in the number of cells but with increased alcohol and CO2 production. Alcohol and CO2 are produced in equal amounts based on the following formula:

C6H12O6 -> 2 C2H5OH + 2 CO2 Continue reading “Sake Yeasts”

Brewing salts for your sake brewing water

This article talks about how to adjust you sake brewing water for better sake.

The question I will address this week is one related to water and how to convert the water we have to the water we want. Let’s assume we want to brew our sake with water that is equivalent to Miyamizu, the heavenly water from Nada. For this example the water we will start with is from the Bull Run Reservoir.

You may recall from “Miyamizu – Heavenly Water – The Gold Standard?” that the mineral content of the miyamizu water is:

Miyamizu (ppm)
Potassium 20
Phosphoric acid 5.2
Magnesium 5.6
Calcium 37
Chlorine 32
Sodium 32

Continue reading “Brewing salts for your sake brewing water”