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.

Koji-kin rice
Koji-kin rice.

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.

Koji-kin rice shaker.
Koji-kin rice shaker.

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!

How much moisture? How dry is dry?

How much moisture? How dry is dry?

I decided to do a quick experiment to determine the amount of moisture in my soaked rice. It had been a while since I looked up how to do this and I miss remembered how much time was required. I was thinking that it required 6 hours but in fact the procedure takes 16 hours for the drying phase. This is more than twice the time I was planning. Well, I got started and weighed out two 30g samples each of Hitomebore 90% seimaibuai, Calrose 90% seimaibuai and Calrose 60% seimaibuai. Recall that the seimaibuai is percentage of rice remaining after milling the outer portion away. Having weighed the samples, I added water to one of each of the types of rice to soak for an hour. At the end of the hour, I drained and weighed the rice again and prepared it all to go into the oven at 265°F.

With 10 hours in the oven, I removed the rice and weighed each sample. While 10 hours is a little short of 16 hours I was not willing to stay up till 3AM to complete the experiment. If 10 hours is close enough I’d expect that the dry weight of the wet and dry samples of each type should be the same. This is close to what I found but not quite. The final weight of the wet sample for the 90% seimaibuai was a little lower than the dry samples. Well, at least I know that there was enough time to remove the water weight from the wet samples.

Init Dry Weight (g)Wet Weight (1 hr. soak)Final Dry Weight (10 hr. @ 256F)
Hitomebore 90% Seimaibuai

30

27

30

39

26

Calrose 90% Seimaibuai

30

27

30

39

26

Calrose 60% Seimaibuai

30

29

30

48

29

Based on this data we can see that both the 90% seimaibuai types had 3-4 grams of water weight. This works out to be about 13% of the wet basis (Init Dry Weight). This is well within the range of expectation for table rice. Rice milled to 60% seimaibuai would be expected to have a much lower moisture level after milling and until it has had time to absorb enough moisture to come back to the 10% expected level. The 60% rice used here was milled by SakeOne and shortly after bagged bye Steinbart’s in a sealed plastic bag. So, it is not given the chance to absorb much moisture after milling. This is just what we see in the data as well; only 1 gram of water weight. One gram works out to be only 3% of the wet basis.

Init Dry Weight (g)Wet Weight (1 hr. soak)Soak % increaseSoak % Water
Hitomebore 90% Seimaibuai

30

39

30%

33%

Calrose 90% Seimaibuai

30

39

30%

33%

Calrose 60% Seimaibuai

30

48

60%

40%

As discussed in “Steeping to hit the numbers,” this data shows that having a lower initial water weight results in a higher rate and amount of moisture uptake. Both samples with 13% initial water weight gain only 30% while the 3% initial water weight sample gains 60%.

A moisture content of about 38% after steaming is considered optimal for ginjo-shu koji. Assuming steaming adds 10% moisture content (this is another experiment), we would like to high 28% water weight after soaking on a wet basis. Notice that, the 90% seimaibuai rice is closer to this ideal than the 60% seimaibuai rice.

Based on this it would be a good idea to lower the steeping time some or raise the initial moisture content of the 60% rice to be more on the order of 15% before steeping. Tweaking this a little could improve your sake.

 

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.

Sake Pressing: what method to use?

Sake Pressing: what method to use?

Recently one of the youtube channels I follow, SakaguraKaetsu’s channel, has had a few short videos on pressing. Specifically, they have a couple on filling a fune (P1020493.MOV, P1020548.MOV) and a couple showing the Fukurozuri – 袋吊り- drip process (P1020495.MOV, P1020553.MOV). Watching the great care taken to fill the bags with moromi is really impressive. They leave no wrinkles at all in the bags as they lay down one bag at a time; again, very impressive and labor intensive.

As an aside, SakaguraKaetsu’s channel has hundreds of short videos on just about every aspect of the brewing process. Some are very good while others are not, but all in all, their willingness to take these videos and make them available is a huge service to the community.  Back to the topic at hand…

When it comes to pressing, if you want to get the absolute best sake out of a batch you should use the fukurozuri method to produce Shizukazake – 雫酒 – or Shizuku – 雫 – for short. This method is very simple, just fill a bag with the fermenting moromi, tie it up so that it hangs above a collector for the dripping sake and let it drip. The resultant sake, slightly greenish yellow is by no means clear. Time will clear much of this as suspended matter precipitates out of solution. Sake, separated from the kasu (lees) in this manor is the best it can be!

The use of the fune – 槽 – is more common than the use of the fukurozuri method. It was once the main method used for pressing the moromi, shibori – 搾り- but has now been mostly replaced by the Assaku-ki. Fune pressed sake is second to shizuku in quality. It is close though and extracts much more of the sake than can be collected using the drip method. The first extracts of the fune, shown at the end of the second video, is very similar in color and clarity to what is produced in the fukurozuri method. However, what we are looking at in this case is sake only under the weight of other bags of moromi. Eventually a lid will be placed on the fune with a tremendous force used to press down on the lid and squeeze the sake from the kasu.

Joso -上槽 – the more formal name for shibori, is now most commonly done using an assaku-ki -圧搾 機 – press. The most well-known producer of assaku-ki is Yabuta. This method is far more efficient in pressing the sake from the kasu than these other two methods but still maintains a reasonably high degree of quality. There is almost nothing to see when a Yabuta is in use but I did find one video of an active Yabuta and one with the kasu being removed (Yabuta in action, P1000134.MOV). The reason there is nothing to see is because of the way the Yabuta works. It uses air pressure to squeeze the kasu, forcing the sake out through the mesh. The loud noise is the air compressor. Yabuta’s chart on the functioning of their machine is quite informative. For the most part, a pocket between two filters is filled with moromi and a bladder is then filled with air to force the sake from the lees. With the sake removed, the kasu is scraped off the filter and the process is repeated until all the moromi has been processed.

Homebrewers are unlikely to have an assaku-ki available for their use but the other two methods, modified for scale are well within reach. The fact that these methods tend to produce better sake does not hurt either. The only down side is the lower efficiency but in small batch production quality over efficiency is usually a good trade-off.

Measuring your Sake – Part four: Amino San-do (アミノ酸度)

Measuring your Sake – Part four: Amino San-do (アミノ酸度)

In part one I talked about how to measure the Nihonshu-do or Sake Meter Value (SMV) or your sake. In part two I covered how to measure the Arukoru bun (アルコール度数) or Alcohol percent by volume (%ABV). In part three I covered how to measure the sando or acidity of sake. In this part, part 4, I will cover how to measure the amino sando of your sake.

As is the case for measuring the sando, you will need some Sodium Hydroxide (NaOH) solution usually at a concentration of 0.1 Molarity (M), phenolphthalein, a small beaker to mix the sample and chemicals in, and a syringe to measure with. All of this can be purchased as a wine acid test kit. In addition you will need some formalin1 solution. As is the case in measuring sando, you can use the phenolphthalein as an indicator or a pH meter to determine the point at which the pH reaches 8.2.

The method used to measure the amino sando is very similar to the method for measuring sando. In fact, it incorporates the sando method as the first step in measuring the amino sando. This is because amino sando is just a specialized acid that is locked up and hidden in the structure. To measure the amino sando we must first remove or neutralize other acids so that they are not counted along with the amino acids. This is accomplished in the first titration step which determines the amount of base require to neutralize the acid. After our sample solution has been neutralized there are no more extra H+ to worry about and we can focus on how to make the amino acids visible, or at least measurable in some fashion. This is done with a formalin solution. The formalin solution reacts with the amino acid freeing an H+ from each amino acid structure. This free H+ can then be locked up using a base just as we did to measure the acid levels. So, one more round of titration using our base solution, sodium hydroxide (NaOH) will give us the level of base needed to neutralize the newly exposed acid so we can calculate the amount of amino acid as glycin, the simplest amino acid.

If that seems a bit intimidating, don’t worry, we will take it step by step from here.

OK, first we need to measure out 10ml of sample sake to evaluate. Place this in a beaker and add a few drops of phenolphthalein. The drops are not needed if you will use a pH meter. Load the syringe with about 10ml of NaOH and record the exact amount in the syringe for later reference; call it R1.

At this point, it is time to add, drop by drop the NaOH from the syringe to the sample watching for the indicator to change color to a light ping for at least 30 seconds. Swirl the sample after each drop as you go. If on the other hand you are using a pH meter you should gently stir the sample with the meter probe to get a correct reading. Once the color changes and holds its light pink color for at least 30 seconds you have neutralized the sample. Record the NaOH level now present in the syringe; call it R2. The difference between this and the earlier recorded level, (R1-R2) can be used to determine the sando (acidity).

Up until this point the procedure has been the same as measuring the sando. It is at this point that we depart from the sando method. Set the neutralized sample aside for use once we have a mixture based on the formalin ready.

Mix 50ml of formalin with 50ml of distilled water. Using the same titration procedure, neutralize the mixture at a pH of 8.2 or where the indicator turns light pink for at least 30 seconds. Remember to add several drops of phenolphthalein if you are using the indicator. There is no need to record the amount of NaOH used for this procedure.

OK, we are ready for the final step. Measure 10ml of the neutralized sample and 10ml of the neutralized formalin mixture and place in a beaker for a total of 20ml. Reload the syringe with NaOH and record the amount contained; call it R3. If you have been using phenolphthalein there should be enough present without any addition. Titrate this 20ml sample until it reaches neutrality at pH of 8.2 or until the color changes to a light pink for at least 30 seconds. Record the final level of NaOH in the syringe; call it R4. The difference between this and the previous recording will be the amount of NaOH required to neutralize the amino acid; (R3-R4).

Having completed all the measurements, it’s time to calculate the levels. First, as before for sando:

TA(g/L) = MoleRatio* (BaseMolarity * BaseVolume * MoleMass) / SampleVolume

=>

Sando = TA(succinic g/L) = ½ * (0.1M*(R1-R2)ml*118) / 10ml

And similarly for amino acid:

TA(g/L) = MoleRatio* (BaseMolarity * BaseVolume * MoleMass) / SampleVolume

=>

Amino Sando = TA(glycin g/L) = 1 * (0.1M * (R3-R4)ml * 75) / 20ml

Where the BaseMolarity is the concentration (moles / liter) of NaHO in distilled water, BaseVolume and SampleVolute are the amounts of NaHO and Sample solutions in ml.

Succinic acid, along with malic and lactic acid are the most abundant acids in sake. As discussed in part three, succinic acid has a reaction ratio, MoleRatio, with NaOH of 1:2 giving rise to the ½ in the Sando equation. The amino acid glycin reacts with NaOH in a 1:1 reaction giving rise to the multiplier 1 in the Amino Sando equation.

The molecular mass (MoleMass)of succinic acid is 118 while the molecular mass of glycin is 75. As you see, these have been substituted in the equations above.

Using a pH meter can be slower and more tedious than using phenolphthalein but the pH meter will be more accurate. In either case, any amount that you are off on any of the titration steps, first for sando, second for formalin or the final step for amino sando, will throw off the following step or be thrown off by the previous steps; that is, the error will accumulate with each step.

Another thing that should be understood and kept in mind when working with NaOH is that its concentration will change over time. NaOH reacts with CO2 in the air neutralizing its base character.  You can use Hydrochloric acid (HCl) to determine the strength of the NaOH solution. HCl is stable so, while NaOH is changing, HCl will remain constant and able to measure the new/ current strength of the NaOH concentration using the same titration methods used above. Maybe I will discuss this in more detail in a future article. [12-10-11, well I added a post on this. You will find it here]

Well, there you have it, the procedure to measure the sando and amino sando of your sake.

  1. Formalin is a saturated solution of formaldehyde at 40% by volume or 37% by mass.

Sake Filtering – Is this Muroka (無濾過)?

Sake Filtering – Is this Muroka (無濾過)?

OK, so the bodai moto based sake I am working on, rested for about 1 month after pressing. Normally, I would have racked it after a couple of weeks but the lees were just not dropping out. I have not had a sake that was so slow to drop its leas before. After one month the sake appeared as in the picture below:

Bodai-moto One Month After Pressing
Bodai-moto One Month After Pressing

Not very encouraging in turns of being able to recover a large percentage of the sake as clear sake. Anyway, I had been thinking about filtering sake and thought that this maybe a good batch to give it a try with. You may recall that the fermentation went very slow and I pressed it too early despite it having had more time to ferment than most. The moromi went through stages of smelling like green apples, strawberries and finally banana’s. These aromas have been very strong and are very evident the minute I open the cooler. At one month after pressing the banana aroma continues to be very strong; Ginjo-ka on steroids.

The equipment I used for filtering consists of a 5 gallon Cornelious keg, and a plate filter with a 7 micron filter paper. I also have 3 micron and 1 micron filter paper but I was afraid that the filter would clog and I would lose too much sake. As it turned out the filter was very close to being clogged if not actually clogged at the end of pushing about one gallon of sake with leas through it. The following picture shows the front and back sides of the 7 micron paper filter and the back plate of the filter housing. Continue reading “Sake Filtering – Is this Muroka (無濾過)?”

Ode to the rice farmer

Ode to the rice farmer, 2011 California Rice Farming

This week I thought that it would be interesting to look at the rice production in the US. This quick look will actually be narrower than the whole of the US in that I am using material exclusively from the Sacramento Valley in California. However, many of the themes will be true for the US and are in stark contrast to what we often see related to rice for sake, our primary interest.

I have been watching the youtube channel RiceNews for a couple of years now and find it to be very interesting. All of the videos here have been selected from their offerings.

While the rice farming families in the US can’t go as far back as those of Japan can, many of those in the Sacramento Valley go back to the beginning of California production.

In the following, I have pulled together views into each stage of rice growing. There was nothing on drying, husking, milling and bagging so that is a missing piece. Maybe I can fill that in some time in the future. Continue reading “Ode to the rice farmer”

Possibly the first ever Bodai moto made outside of Japan!

Possibly the first ever Bodai moto made outside of Japan!

I have just completed the pressing of a sake made with a bodai moto and while the story is still not complete I think this may be a good time to look at what we have so far. The bodai moto is the original method of creating a moto. As I have written before in this venue, the bodai moto was created from a sake brewing method known as bobaisen. Bodaisen was sake made using the same method used for bodai moto but there is no additions added later. For bodaisen you put all the ingredients together at the beginning and then ferment to the end with no additions. Over time it was found that adding a bit of the mash of a good brew to the beginning of a new brew helped make better sake as well as make it more reliable. As the properties of the sake improved while adding a “starter” from a good batch, this became the norm and even the first batch needed to have a starter and this push for better sake is how the method for making bodaisen became the method for making bodai moto.

Bodai moto is also called mizumoto or water moto. The name mizumoto makes a lot of sense once you begin to look at the method used and what it produces. The outcome of the first step of the method is a special water called soyashi-mizu that contains, along with the water, lactic acid that will protect the moto and the ferments made with this moto. There are also other compounds from various bugs that became active before there was enough lactic acid to kill them off. These bugs and their effect on the moto bring distinctly different contributions to sake. Similar to yamahai moto sake, bodai has its own funk.

To start a bodai moto we need to make the soyashi-mizu. Soyashi-mizu is created in the soyashi process which consists of mixing a small amount of cooked rice with raw rice and water and letting stand until the lactic acid reaches the desired strength. Now I should say that in the original process this is also key to cultivating a good yeast population. Because I will add yeast I am not really looking for this but it may also be a strong contributor to the resulting characteristics. Continue reading “Possibly the first ever Bodai moto made outside of Japan!”

Hitting your SMV (Sake Meter Value) – To ameliorate or not

Hitting your SMV (Sake Meter Value) – To ameliorate or not

One question that comes up over and over in sake brewing is how to hit the SMV value desired. Puzzling over this question I asked one of the brewers from Yoshi-no-gawa when the opportunity presented itself. This was well over a year ago now, but what he told me was that they monitored the moromi (main ferment) and when it reached their desired SMV value, it was time for Shibori or Joso, that is time to press the lees from the sake. Using an assaku-ki machine (an accordion like press), often referred to as a yabuta, they are able to remove virtually all of the lees and even the yeast. Because this leaves only trace amounts of the yeast, fermentation is stopped and the SMV value is stabilized.

Very nice! However, if you have seen my videos of the pressing process you may be wondering if something is amiss. Well, yes, something is amiss. My pressing method leaves a large amount of the lees in my sake so there is no way I am removing the yeast. This is true for most homebrewers. There are filters used for brewing that may be able to do what is needed. I have one but have not used it yet. In any case to use it I will have to first press and let settle or fine before filtering because the amount of lees would hopelessly clog the filter if the sake isn’t pretty close to clear. So, for now, I can’t use their method.

Continue reading “Hitting your SMV (Sake Meter Value) – To ameliorate or not”

An old enemy of Saké – Hiochi-kin (火落菌)

An old enemy of Saké – Hiochi-kin

An old enemy of Sake and the sake brewer is Hiochi-kin or hiochi bacteria that spoils sake as it grows and reproduces. Unlike most bacteria (bugs for short) hiochi-kin does not mind alcohol and some even like alcohol. So as most Lactobacilli, which are heavy lifters in Kimoto and Yamahai moto styles of sake, will die off as the alcohol levels increase hiochi-kin does not. The other factor that usually keeps the bugs out is low pH levels like those found in sake which are a result of acids created in or added to the moto. However these hiochi-kin also like low pH, highly acidic environments.

As it turns out, hiochi-kin is a lactic acid bug or more specifically it is one of two bugs Lactobacillus (L.) homohiochi and L. fructivorans (a.k.a. L. heterohiochi).  These are the “true” or “obligate” hiochi-kin and need hiochic Acid (more commonly known as mevalonic acid) for their growth. Other hiochi-kin or sake spoilage bugs are referred to as “facultative” and include: L. fermentum, L. hilgardii, L. casei, L. paracasei and L. rhamnosus.

Koji produces the needed hiochic acid. The fact that “true” hiochi-kin need hiochic acid implies that these bugs are highly adapted to sake production.  Thus they have few other environments in which they can grow. Hiochic acid is an intermediate compound in the biosynthesis of many other compounds so it is not normally seen in a stable state (i.e., not part of a biosynthesis process). The chemical makeup of hiochic acid follows.

Hiochic Acid Chem
Hiochic Acid Chem

Continue reading “An old enemy of Saké – Hiochi-kin (火落菌)”