Koji – Home Brew Sake

Koji-kin from Scratch, well sorta

How to make koji-kin for sake on your own.

One question I get fairly regularly is how to make koji-kin. Despite this I have failed to take the time to write up a good explanation for all of you. Well, no longer. In this article I will explain just what it takes and how to do it. Almost all you need to know is in my “Video Series and Instructions for making koji for sake” at: link. The only thing missing for making koji-kin from that source is that you need to sustain the last stage longer. That is, don’t spread out and cool the koji once it has completed its coverage of the rice. Rather, continue to monitor the koji so it does not get too warm or cold. It will start to show signs of a greenish yellow tint. This will progress into a darker greenish yellow color and begin to cover each grain. Once fully covered, carefully spread out the koji to cool. The green covering has lots of tiny spores that will come off so you’ll want to minimize disturbing it. After it has cooled, it needs to be dried so that other contaminates will not find it to be a nice home. Once FULLY dry, and I mean dry, you can place it in a shaker for later use.

The following picture is some koji-kin rice I have made. Some people will grind this into a powder but I’d use it as is.

One way to use it is to put it into a shaker like the one in the following picture. It was purchased at a kitchen supply store and is often used for powdered sugar and the likes. It works well for koji-kin rice.

Using this shaker and koji-kin rice to shake over a piece of paper I get the pattern in the following picture.

Koji-kin from shaker. — Koji-kin from Shaker.

If you regularly make koji for your sake, you can, as needed, increase the batch size by 50% and after collecting and cooling the koji when ready, let the rest continue on as described above. This lowers the extra effort required for making your own koji-kin sense you were doing all most all the work needed already. Care must be taken to ensure the koji intended to continue on to koji-kin does not lose its warmth. Its smaller batch size will not hold its own generated heat as well as the larger batch.

Let us know if you make your own koji-kin and what your experience has been like!

Shio-koji?

Shio-koji? What it is and how to make it.

Recently, there have been a few different articles and mentions of shio-koji. I had never heard of this until these articles. I came across shio-koji through a chain of retweets from @seishu and @theprovenance originating with @ChrisPellegrini Anyway, these tweets were pointing to an article by Makiko Itoh in The Japan Times: Kōji — Japan’s vital hidden ingredient. Of course the thing that caught my eye was the use of koji. I am familiar with amazake but shio-koji with a third of the koji’s weight in salt? That seems like a lot of salt to me but most of the articles seem to imply that shio-koji used as a replacement condiment for salt would reduce salt intake.

Having read Makiko-san’s article, I thought it was interesting and that I should give it a try some time. Really was not thinking about doing this anytime soon though. Then I saw another reference and another… What is going on with this stuff. Finally @keyope put up a page (now gone) with the amounts of all three ingredients, koji, salt and water. This matched very closely with almost every other recipe I see so what the heck, I’ll give it a try.

I didn’t want to make a lot so @keyope’s recipe size seemed just about right to me; only 30g of salt, 100g of koji and 150ml of water. I combined this together this morning and stirred them up. They are sitting on the counter now.

It turns out that 150ml of water is too much for use with my fresh koji. It would probably be a better amount for use with koji like Cold Mountain’s. I guess the best advice here is to add a little, maybe 100mls worth in this case and then add more if needed.

This stuff is pretty salty tasting but we will have to wait about a week to see how it turns out with the koji enzymes transforming the basic ingredients. I’ll add and update in a week.

First “Special Ginjo” Koji-kin for homebrewers!

We have just added the Akita Konno “Special Ginjo” koji-kin to our offerings in the store. This new koji-kin has been developed at one of Japan’s leading koji-kin suppliers specifically for making Ginjo sake.

Unlike most koji-kin available for homebrewers, Akita Konno’s special ginjo koji-kin is specifically for making sake. We provide two 1 gram packets, each of which will make more than 3 lbs. That’s enough for two standard batches of sake.

The instructions provided have been reviewed by Akita Konno to insure the information given meets their high standards.

New Page on Koji Making with Video

OK, so I have finally pulled together a complete page on making koji for sake brewing along with the videos. As with the videos for brewing sake there is nothing amazing here but that may, in fact, be the amazing thing. When it comes to making koji, like brewing sake, it is all very doable.

I believe the text for the koji making page is very readable and stands on its own without the videos. However, the videos may help to solidify what is said in the text. All in all I hope you find the page useful and enlightening!

Oh, FYI, I have linked the koji making page into the top of the Recipe page for convenience.

Aroma during koji production

Today as I am making a test batch of koji that I am working on as a new offering (Special Ginjo Koji-kin), I am led to thinking about the aroma of the growing koji. What is that smell? Where does it come from? Well it seems that the answer, at least at the level I can discuss here, is not that complicated.

The aroma of a fresh batch of koji is often described as being chestnut like. This aroma was noticeable during my check of the growing koji at 20 hours into the process, not strong but definitely there. As the time goes by the aroma is strengthening. I am not sure if I would equate the smell of koji with chestnuts but I find the smell nice and even comforting. So what is making this aroma?

It seems that the aroma is coming from a combination of phenylacetaldehyde, 1-octen-3-ol and 1-octen-3-one. Production of phenylacetaldehyde seems to stop at around 40 hours into the process while the production of 1-octen-3-ol and 1-octen-3-one continue and can even double their concentration during the final stages of koji production (hours 44-50). However, as 1-octen-3-ol and 1-octen-3-one concentrations overwhelm those of phenylacetaldehyde a more mushroom like aroma becomes noticeable. Individually phenylacetaldehyde and 1-octen-3-one have a rose like and a mushroom like aroma respectively. Continue reading “Aroma during koji production”

Koji production – what are we trying to do?

OK, so what exactly are we trying to do when making koji? Well, to examine this we need to consider the role koji plays in Sake Brewing. In sake brewing we use koji to provide a wide variety of products. These include products that provide flavor and aroma elements as well as enzymes which degrade proteins and starches into smaller component parts. For example proteins are disassembled into peptides and amino acids while starches are converted into smaller starches, dextrins and sugars.

Rice starts out with 7% to 8% protein, but much of this is milled away, so we do not focus on koji’s production of enzymes to break down this protein. Rice starch is our main focus and needs to be broken down as effectively as possible into sugars. Koji produces alpha, beta and gama amylase. Depending on how we culture the koji, we can emphasize protein or starch degrading enzymes. High temperature cultivation, 98°F to 110°F, lead to the production of saccharification enzymes whereas lower temperature cultivation, from 98°F down to 68°F, emphasizes protein degrading enzymes. So to make good koji for sake brewing we must culture the koji at high temperatures.

Continue reading “Koji production – what are we trying to do?”

How much sake does a pound of rice make?

I recently saw a section in “The Niigata Sake Book” labeled “How Much Sake Is Made out of 1 kg (2.2 lb.) of Rice” and thought this would make a nice topic to cover. I may later do a more in depth look at this but for now we will just get a good idea of the basics.

OK, so if we start with rice, water and some microorganisms how much sake will we get? Well, let’s start with brown rice as does “The Niigata Sake Book.” To make sake starting with brown rice the first thing that needs to be done is to polish the rice to a level needed for the type of sake we wish to make. To get down to the edge of junmai ginjo type sake we need to polish the rice to 60% or less. So let’s say we will mill the rice down to 60% of the original brown rice. That is, if we start with 1 lb. of brown rice this will leave us with 0.6 lbs. of white rice.

Now, for this there is a key ratio that needs to be understood. While this ratio will change somewhat for individual sakes, we will simply choose a reasonable example ratio for this analysis. The ratio of water used to the weight of rice added is around 1.3x, so that is what we will use. This implies the water needed for the fermenting mash will be 0.78 lbs. = 0.6 lbs x 1.3. The fermenting mash (the Moromi) will then be 1.38 lbs. = 0.6 lbs. rice + 0.78 lbs. water.

Continue reading “How much sake does a pound of rice make?”

Amazake – it ain’t sake

I have meant to post a little something about anazake for some time but I keep putting it off. Now that I have gotten a question about how to make it I can see that it is overdue and I should get my act together. Amazake is a rice and koji mixture that is most thought of as a drink but has other uses as well.

OK, so to make amazake you need koji and rice. You can make koji with the method discussed in the earlier post, “Making Koji for Sake.” In this case you will need to start with koji-kin. If you prefer you can skip making your own and just buy the koji. I have both koji and koji-kin in the store.

Once you have the ingredients, koji and rice, cook 3 cups of rice just as you would to eat the rice. When cooked, thoroughly mix 1 cup koji with the now 3 cups of cooked rice. Leave this in a warm area (75F-85F is good but could be as high as 140F) for between 6 hours and 12 hours. You should stir this every couple of hours; each time tasting it. It should get sweeter and sweeter until it stabilizes. When it stops getting sweeter it is done. At this point it should be quite mush like. Put it in a sauce pan and boil it for 5 minutes but be careful not to scorch it. This denatures the enzymes and stops the transformation. Continue reading “Amazake – it ain’t sake”

Making Koji for Sake

In order to make koji for brewing sake we need to go through the same steps that we do to prepare rice for brewing sake. In fact, it is often the case that a portion of the rice goes directly into the brewing sake while another portion is used for koji. So, as always we begin by washing the rice. This is to remove all contaminates, including the powder (Nuka) that remains after milling and any material added by the miller, like iron. Removing the nuka lowers the stickiness we will have after steaming. And, as mentioned elsewhere, iron is very bad for sake as it darkens the sake and speeds a reaction of residual sugars with amino acids that harms the flavors and aromas.

Washing the rice is followed by steeping the rice until we reach the desired water uptake level, usually between 25% and 35%. If the uptake of water is too little the rice will not steam properly leaving a hard uncooked center that the koji mold will not penetrate. On the other hand having too much water uptake will cause the rice to be too mushy and sticky after steaming. This results in a base that is too easy for the koji mold to penetrate and this prevents or lowers the production of transformative enzymes we want. Most rice used for hombrew sake will need to steep between 30 minutes and two hours. As homebrewers we are more often than not more guilty of soaking too much than too little. Continue reading “Making Koji for Sake”

How Sake is Brewed

Brief introduction to how sake is brewed.

Sake is brewed in a strung out process that can take quite a long time but none of the steps are particularly difficult. In the traditional method, brewing sake starts with the rice and its milling. The objective is to remove the outer layers of the rice which cause sake to be less stable and to have harsher flavors. These layers contain the bran and the highest concentrations of oils, fatty acids, proteins and minerals like magnesium and iron. Table rice (white rice) is generally milled to around 93% of its original size. Sakemai (Sake Rice) is usually milled somewhere between this for futsu-shu (table sake) and 35% for the most refined Daiginjo. Removing these components leads to a more stable and refined sake.

Once the rice has been milled to the proper level we need to steam the rice. We used steamed rice both for making koji and to directly add to the brew. In order to steam the rice properly we need to first wash the milled rice to remove the outer layer of rice flower, talc or whatever may be on the rice. After a good washing the rice is soaked to absorb the needed amount of water for proper steaming. This amounts to about 30% by weight. The higher the milling rate the faster the rice will absorb the desired amount of water. Kurabito (brewery people) working with the most highly polished (Milled) rice often use a stopwatch to time the soaking period so the rice does not take on too much moisture. Here the goal to get enough moisture into the rice so that the steaming process gelatinizes the rice by heating the water already there. If the rice has too much moisture it will become soggy / mushy during the steaming process and will not form a nice home for koji. Continue reading “How Sake is Brewed”