The 3 Types of Fermentation: Where Does Sake Fit In?

Greetings Sake Lovers, welcome to another KURAND Magazine article that introduces you to the world of sake.

Sake is a fermented beverage made from rice. But exactly how is it fermented and how does the process differ from wine and beer. That is the question this article will attempt to answer. We will look at the three main types of fermentation and reveal where sake fits in.

How fermented alcohol is produced depends on whether or not there is any accessible sugar available in the raw ingredient, to begin with.

There are three main fermentation methods.
Please refer back to the below diagram as you read through this article.

Single Fermentation (sugar to begin with? = yes)

This is the one used to make wine. Alcohol beverages in this category are made with a raw ingredient that contains accessible sugar to begin with, often a form of fruit. With sugar already available, all you need to do is add yeast. The fruit is normally crushed to make it easier for the yeast to access the sugar. The process of making wine is referred to as single fermentation.

Multiple Fermentation (no sugar to begin with? = No)

This is how beer is made. Unlike single fermentation, the raw ingredient, the barley does not contain accessible sugar and this is what the raw ingredient of all beverages made with multiple fermentation have in common.

Multiple fermentation gets its name from the fact that two processes are required before fermentation can take place. The core constituent of barley is starch. Starch is basically the plant’s space efficient way of storing glucose, the energy it needs to grow, but the important point is that starch cannot be accessed as glucose without another step. When the plant starts to grow, powerful enzymes are released from the germ which breaks this starch back down into glucose for the plant to access. Malting is essentially the forced growth of the plant. The scientific term for the process is germination. In fermentation, the conversion of starch to sugar is called saccharification. The saccharified barley is called wort. The word is basically a sugary liquid. Yeast is then added to the wort and alcohol fermentation proceeds in the usual way.
The process of making beer is referred to as brewing because boiling and steeping are required.

So which one of these two categories do you think sake would belong to?

You might think multiple fermentation, and you would be warmer rather than cold, but although sake is much closer to beer than wine—the process of making sake is also referred to as brewing—the correct answer is in fact: neither.

Despite all the similarities with beer brewing, the fermentation method used to brew sake is completely unique.

Multiple Parallel Fermentation (no sugar to begin with? = No)

Whereas in multiple fermentation, the two processes are carried out simultaneously, in the method used to brew sake, they are carried out in parallel. Don’t worry if you are still confused because we are about to elaborate.

The key difference between barley and rice is that the outer layers of the rice grain are nearly always removed to avoid unwanted off-flavors in the end product, a process called polishing. However, this polishing also inadvertently removes the germ. Remember, the germ is where the plant stores its starch-converting enzymes.

Therefore, it is not possible to germinate rice like barley. So how do we convert that starch into sugar?
Luckily there is a mold that can produce the required enzymes. The mold is called koji. This koji is inoculated into steamed rice. Instead of malting, we essentially create moldy rice. The mold secrets its enzymes into the rice. Still with us? It only gets a little bit more complicated from here.

The moldy rice which we conveniently but rather confusingly name after the mold, so, koji, becomes a standalone ingredient in the process that we add to a massive tank together with steamed rice and water a seed fermentation—a smaller baby fermentation we made earlier—that contains a healthy population of yeast.

It is in this tank that a miracle takes place that sets sake apart from both wine and beer. The koji breaks up releasing the enzymes and some already converted glucose into the water. At the same time, the steamed rice breaks up and releases extra supplies of starch into the water. The water acts as a catalyst that brings the starch into contact with the enzymes and vice versa (the process is actually a type of hydrolysis). As the same time that the starch is converted into sugar, yeast eats this sugar and creates alcohol. This cycle repeats itself over and over until the desired product is complete.

It sounds miraculous that these two processes can coexist and play out in parallel, and it is.
The balance and control that is required to keep these two processes from outrunning each other, makes sake production one of the most complex and difficult in the world and is unique to Japan.

The constant supply of glucose throughout the fermentation is why multiple parallel fermentation achieves the highest alcohol strength among fermented beverages and can get as high as 20% alcohol, but it is not a spirit.

So there you have it, sake is not a spirit, it is not a wine, it is closer to a beer, but it is not a beer. In short, sake is a unique miracle of Japan and should be celebrated as such.

Bonus fact: unlike beer, sake is brewed in an open tank which means that, with a few exceptions, all of the CO2 gas dissipates as opposed to dissolving into the final product. Therefore, sake is rarely naturally bubbly like beer, certainly not to the same extent as beer.

If this article has inspired you to learn more, it is never too late to begin your journey into the world of sake.

KURAND provides the perfect setting to discover sake on your own terms, at your leisure, without any time limits and without burning a hole in your wallet.
Why not pop into KURAND the next time you are in Tokyo where you can taste over 100 different types of sake, carefully selected from all over Japan. We look forward to welcoming you soon.