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Making Koji for Homebrewing Sake - The Taylor-MadeAK Way
10/17/08
09:05:26 pm by Bob Taylor, Categories: Homebrewing, Sake , Tags: homebrew, homebrewing, koji, koji-kin, kome-koji, sake, tane-koji 
Introduction
Greetings! Welcome to the beginning of a series of followups that I'm writing in an effort to plug some of the holes in my wildly popular How to Make Sake at Home guide.
When I make a batch of sake, I normally buy some Cold Mountain Dried Koji from my local ethnic supermarket to satisfy that ingredient requirement in my recipe. I understand, however, that this product is not available in all parts of the world and therefore is sometimes impossible for hopeful sake homebrewers to get their hands on. Cold Mountain Dried Koji is a dried product, but it's still heat sensitive and requires refrigeration, which makes mail-ordering problematic at best.
The alternative, as pointed out in the main guide, is to grow your own koji using non-perishable koji-kin (the spores of aspergillus oryzae mold) that is readily available on the supplier's web site and from many homebrew supply stores (my LHBS stocks it). Growing your own koji from these spores is certainly economic: one 10-gram package contains enough spores to inoculate about four normal size batches (3 cups dry rice, 6 cups steamed). Also, making your own koji will allow you to take control of the quality of this single most important ingredient used in making sake.
Vision Brewing supplies instructions for using their koji-kin to grow your own koji. Following those instructions in spite of their vagueness will produce koji for you, but be aware that the amount of koji described therein is half of what you will need for a normal size batch of sake when brewing the Taylor-MadeAK way.
The full details of this process follows after the jump.
Follow up:
Equipment
Koji is generally considered to be the most important ingredient in sake, and this is taken so seriously by traditional Japanese kura (sake breweries) that they dedicate special rooms just for growing their koji. These are nice rooms, too: paneled with nice wood, with lots of nice wooden trays to keep the incubating koji in, and temperature and humidity levels are rigorously controlled.
As homebrewers, we don't have to dedicate an entire room to this process, but we should respect it enough to give it the personal space it requires. Besides, we wouldn't be homebrewers if we weren't looking for excuses cobble together new equipment to suit a task, right?
So, here's my recommendation for equipment, inspired by dray's topic over on the Northern Brewer board:
A Coleman 28 quart insulated cooler. Here at the end of Summer (end of Autumn for us Alaskans, judging by all the snow on the ground), all of the coolers are on sale for pretty cheap at your local box store. I grabbed this particular model one day because I needed to transport my daughter's ice cream cake, and it was just big enough to do the job. So, I happened to have it lying around for this project. No modifications are necessary, but it happens to be just big enough to hold....
A one-gallon capacity, flat Rubbermaid "TakeAlong." My wife buys these all the time for taking cookies to work in, so we always have a bunch lying around. They're lightweight, fairly durable, flexible, dirt cheap, and come two to a pack. The lip on this vessel is just sturdy enough to hold it nice and snug in the top of the cooler while it's full of rice, and still allows the cooler's lid to seal. This leaves room between the bottom of the "TakeAlong" and the bottom of the cooler for some temperature management.
A common heating pad. These are available in a multitude of styles and most homes just happen to have at least one lying around. Few items are better at multitasking than these devices (I often use ours to melt chocolate and incubate yogurt). Mine is folded in half and stuffed inside a gallon-size zip-top freezer bag to protect it from any condensation that forms inside the cooler. This is good to keep things warm, but you still need to have a way to keep it in check.
A temperature controller. If you've been brewing beer or making sake for a while, you probably already have one of these. The important part, in this case, is that it needs to be a model that is capable of both cooling and heating applications. The Brewer's Edge CONTROLLER II pictured here has an internal jumper that can be moved to change it from one application to the other.
Humidity control is just as important as temperature control for making kome-koji. Referring back to dray's example, it's been found that covering your incubator's sub-vessel with cellophane plastic wrap may help keep the rice from drying out while the koji grows on and into the grains. You can try the plastic wrap, but I'd rather stay away from it. You see, the aspergillus family of molds are all highly aerobic, so sealing it up air-tight with some plastic wrap probably isn't a very good idea. Instead of the plastic, I placed a small plastic cup half-filled with filtered water on top of the heating pad. The heat evaporates enough of the water to noticeably raise the humidity in the incubator and prevents the inoculated rice from drying out. This is something that you may want to keep in mind when making your own koji.
Rice steaming equipment. I'm not going to re-hash the rice steaming instructions here, but I do want to re-stress the importance of it. See, when you steam rice you're only pushing enough water (about 30% of the rice's dry weight) into the grain to hydrate and gelatinize the starch. This means that steamed rice, while fully gelatinized, is still very firm and pretty dry compared to simmered rice. This is important to remember because the soft grain structure and high water content of simmered rice allows the enzymes that the mold produces to reduce the rice to an unusable puddle of goo. It is for this reason that rice prepared in any other conventional cooking method is completely unsuitable for turning into kome-koji.
I don't want to seem like I'm downplaying the importance of the rice itself, so I'll mention that in this example I'm using the same Kokuho Rose rice that I normally use to brew my sake. You can, of course, use whatever kind of short or medium grain rice you like. If you want to resurrect the old Japanese tradition, you could even use brown rice to make your kome-koji
A very small, very fine sieve. This will be used for distributing the koji-kin onto the steamed rice once it has cooled. I use this one for distributing ground spices, and I think I paid all of $1.50 for it at Wal*Mart. The all-steel construction is important for sturdiness and for ease of sanitizing. I just give it a dunk in some iodophor and shake until it's completely dry. If you don't have or can't find one of these, you could follow dray's example and double up a piece of cheesecloth around a measuring spoon and use that to distribute the spores. It's more wasteful than the sieve because a lot of the powdery spores will inevitably get stuck in the cloth, but it'll get the job done.
A cleaned and sanitized aluminum half-sheet pan. Just about every home in America has some of these around. That goes double if you're married and redoubled if you have children (mothers like to bake for their kids, right?). Aluminum, being metal, is easy to keep clean and sanitizes very well. It's also an incredibly good conductor, which is good news when you have six cups of very hot steamed rice that you need to cool quickly without being able to add cold water to it.
42 comments
I used an electric roaster with a couple inches of water to create a warm, moist growing environment and it worked well, although required constant temperature monitoring.
Looking forward to starting the next step tonight!
As I wrote in this guide, I kept the inoculated rice in the 86º-88ºF range throughout its entire time in the incubator, but after 30 hours the temperature started rising past 90ºF very quickly as the mold kicked its metabolism into high gear. After 45 hours I called the koji "done" and moved the bulk of it to my freezer, but in the name of experimentation I left some in the incubator.
To encourage the mold to sporulate, I left the temperature controller set to where it was and removed the cup of water I was using to keep the humidity high, but did nothing else to encourage drying. Whether or not this is actually necessary I can't say because I've only done the experiment once. It's possible that the only factors that aspergillus oryzae needs to sporulate are high temperature and time - humidity, or the lack thereof, may be irrelevant to the mold reaching maturity once it has metabolized enough of the rice starch.
I do really admire your work,sir, and I appreciate your focusing on the enzymatic saccharification potential of the fungus Aspergillus Oryzae. I ordered 1 sachet of Koji-kin from the Australian Company
http://www.tibbs-vision.com/sake/
one year ago and I managed not only to propagate a spore culture on steamed rice but also on steamed wheat and quinoa kernels. I do sincerely recommend you also to seek out the possibilities in using koji-kin to produce your own homemade soy sauce (sho-yu), miso or even unmalted beer. I just recently started creating a Blog concerning these matters, so I look forward to reading more from you.
Kitchen laboratory experiments make great fun!
I am about to start my first batch of Koji (and, eventually, sake). I am confused about the length of soaking time for the rice. You have called for 18 hours all over this site, but above her, you add this addendum:
I'll update the rice-steaming instructions with this information later, but I timed this particular batch of rice while watching for the aforementioned volume increase: It took just over one hour. That's for regular old Kokuho Rose rice, not some fancy highly polished sake rice. Soaking another batch of rice overnight didn't produce a noticeable increase in volume, but it did result in steamed rice that stuck to my hands tenaciously, where the batch soaked for only an hour did not. So, there you have it: rice being prepared for steaming only needs to be soaked for an hour to absorb the necessary water, not overnight.
Are you changing the amount of time required for ALL soaks, just this pre-Koji soak, or am I not understanding?
Thanks,
Harry Jarvis
Here's what happened: I did quite a bit of research on the matter of soaking rice prior to steaming for any step in the sake making process, and the only consistent answer (where I could find any answer at all) was that soaking time doesn't matter all that much. What does matter is how much water the rice absorbs, which for steaming means 25-33% of the rice's original volume or weight in water.
That makes sense, in a way. Rice is an agricultural product, and as such will differ from harvest to harvest as to how fast it will absorb water. But I performed this experiment anyway: I made two batches of koji in a row. For the first batch, I soaked the rice overnight as I usually do. For the second batch, I put the rice in a graduated container and soaked it until the original volume of the rice increased by 33% - this only took a couple of hours. The results were pretty similar, except that the rice that soaked overnight was stickier (tenaciously so, it stuck to my hands quite badly) than the rice that only soaked for a couple hours.
So, now I only soak my rice for a couple of hours whether I'm making koji or a full batch of sake, but I always watch for that increase in volume. If you're soaking 3 cups of rice, you'll know it's ready to steam when you have 4 cups of rice in whatever container you're using to soak it.
i am going to make my next batch this week. wish me luck
tony
One question that's eluded me: where to get bags for straining the delicious result? I wound up using a lab centrifuge which let me spin down 3 liters at a time - not bad, but not authentic either. I'm currently culturing about 9 pounds of koji for a 5 (or so) gallon batch of sake and would like to be able to filter it correctly.
Thanks!
To separate my sake from its kasu I use a small stainless steel fruit press and inexpensive 5-gallon capacity nylon paint straining bags that I pick up at my local Lowe's hardware store. Not traditional, either, but to date I have yet been unable to find a source for the burlap or canvas bags that are used by sake kura.
I suppose some day I may talk my wife into making some for me. =) Until then, the paint straining bags suffice.
I was checking out the Gem Cultures website and noticed that they had 5 different strains of Koji-ken with one of them listed for sake and the rest for soy sauce and various misos. I didn't realize there were different cultures of Koji-ken until then. Have you tried the Gem Cultures sake spores (which are cheap if you buy the larger quantity) and if so, are they the same strain as the Vision Brewing spores.
I also just made a batch of sporulating Koji for my next batch and I was wondering about long-term ability to grow a mono-culture. It seems like over time the chance of something else building up in the spores that you are using would increase. Obviously just buying new spores from time to time would be a cheap solution.
Thanks,
Chuck
I haven't tried the spores from Gem Cultures, mostly because I prefer to buy things locally when I can to support the small businesses around here. The spores used in my guide were the Vision Brewing ones, purchased from my local homebrew supply shop. What's the difference between those and the Gem Cultures spores? I haven't the slightest idea, sorry.
As for the viability of maintaining a long-term pure monoculture, I don't have any definite answers for that either as I just started growing my own koji last year. I am, however, operating on the working hypothesis that as long as your koji making method is sound and sanitary, you should be able to maintain a monoculture indefinitely. I have two pieces of evidence to back this up.
First is the way the mold itself works: koji produces filaments that coat and penetrate the rice grains just about completely, and is very active about doing so provided you've set up the right kind of environment for it. It's also snow white, so it's pretty darn easy to identify when you have something funky and non-koji growing in there. It's not like yeast where you have a bunch of free-floating microscopic critters in an aqueous solution, and so the only way to get a pure monoculture is to start with a single isolated cell and culture up from there in a rigorously sterile environment.
Second is tradition: the method I describe for propagating spores is pretty much exactly the same method the Japanese brewers have been using for hundreds of years with a great deal of success.
Now you know as much as I do. Good luck on discovering your own answers!
Is any biological activity expected prior to pitching the yeast. 24 hours into letting the rice and koji mixture sit as part of making the moto, there is definitely a little bubbling going on. I think it may be a wild yeast, but I'm not sure.
Do you have a ratio of clear sake/leftover solids to make nigori? Thanks!
I had experimented on a pan of Koji and "held back" causing dehydration where the rice then became tane-koji overnight. Being that now I have a pan of it...I can storage it. Assuming I cannot use it at this growth stage for adding to make sake as an alternative to the 'white?" Storage temps? Thanks very informative!
As for storage, I just keep my tane-koji in a shaker in the cupboard above my stove. Once dry, the rice and spores aren't particularly temperature sensitive. When I want to make a batch of koji, I just take the shaker down, remove the dust cap, and shake the spores on.
Possibly a little too well, because having been very pleased with myself this morning seeing beautiful, white furry rice, I just went to box it up to discover it's all got a decidedly green tinge already and I'm going to have to start over.....
I reserved only 3/4 cup of kome-koji to turn into tane-koji - the very same 3/4 cup illustrated in this guide, by the way - and have since used it to inoculate 4 more batches. In fact, I won't say it's time to make more seed koji until it seems to be getting difficult to get spores out of that shaker. How many batches will that be? I have no idea. But 3/4 cup (more like 1/3 cup now that it's completely dried out) has been more than enough to make more koji with.
Refrigerating or freezing koji doesn't seem to hurt the mold much, if at all. I've had reports from people who have made tane-koji from their own frozen koji as well as from people who have done the very same with Cold Mountain Koji.
I came across this site long ago, well before the radio show brought up popularity and interest. I had a hard time sourcing koji-kin spores to start with so I lost interest and got heavily involved in beers and meads which are more easily sourced ingredient wise.
Now I got my rare and only pack of Koji-kin. My goal is not to make any Sake with it. I only want to make Koji and only tane-koji. So I want to take rice to growing koji to sporulating and then storing up a massive batch of spore laden rice to hand around to other brewers at the local brew club.
If I can do this then and only then I'll start working on actually making Sake from the next batch made from my own tane-koji.
That said, if the only goal is to make tane-koji can I just dispense with the whole expensive polished rice as I'm not seeking flavour attributes, just a cheap base to make nothing but tane-koji. Does short grain rice even matter or can one just use the cheapest available or even long grain and leave the short grain and highly polished rice for when actually making sake to drink?
Pete
The type of rice you use to make tane-koji really doesn't matter. Indeed, the tradition is to use brown rice for that purpose. Why? I really don't know. I use plain old short grain sushi rice to make all of my koji (in fact, I use that rice for just about all of my sake, too) and have never had any ill affects from doing so.
Long grain rice? I honestly don't see why you couldn't use it. It's not traditional, but I can't see why it wouldn't work just to produce some tane-koji.
A 10 gram packet will produce approximately 6 kilos of Malt Rice (rice that has been enriched with enzymes from the growth of Koji mold. I am intending to steam 6 kilos of kokuho rose and inoculate it with the 10 grams of spores. Do you think this will work? I ask because they only provide the 1.5 gram to 400 gram recipe and I can't figure out how to multiply that up to 6 kilos. Thanks for the wonderful website.
The biggest problem you are likely to run into is incomplete coverage of the rice by the mold, which stems from using a sifter or other means to distribute a pre-measured amount of concentrated spores (or spores blended with flour) over a given amount rice. My experience since writing that guide has taught me that I get much better coverage by making my own tane-koji using the vision spores, then using the tane-koji inside a metal salt shaker to distribute spores over my steamed rice. No measuring of spores is required, just shake and mix and repeat until the rice takes on a noticeable green tinge from the spores.
I've done a significant update to this guide. Two very important bits of information have been incorporated:
(1) The impact of incubation temperature on the final enzymatic properties of the koji, including updated incubation temperature ranges. In essence, koji likes to produce mostly protease in the lower portion of its preferred temperature range and mostly alpha amylase in the upper portion. This changes the target incubation temperature recommended in this guide from 85ºF to 96ºF.
(2) This hasn't happened to me, but it's worth pointing out that flour is a possible source of contaminants in your batch of kome-koji. In this guide I try to get around this in two ways: by using bleached flour, and by making sure that the amount of spores I'm using is triple the amount of flour that's being used to cut them. Still, I've added a note about the possible contamination issue, pointing out that the only way to eliminate it altogether would be to omit the flour.
I've also gone back through and tried to make the inclusion of Celcius temperature conversions more consistent.
Anyway, it's worth going back through and re-reading the guide to see the changes I've made. Hopefully it'll help you guys make better koji in the future.
I am making koji with the hopes of making both tane-koji and koji.
Am I to understand that whole rice (not polished, i.e. with husks) are best for making koji and tane-koji?
I was thinking that my whole grain bhutanese short grain rice seems to have a nice structure (solid, etc) and might make for good koji - or am I mistaken? Have you tried brown rice?
I've made koji from Vision spores before, I'll keep you updated. Still no source of red-koji, I have been trying to look for a lab, but no luck yet.
The tane-koji I made I stored in a mason jar with a perferated screen on top. It started to mat together, like fibers. A bit like koji, in fact. Most of it is still green, though, and I'm just curious - does this seem right? I am considering taking a half cup of my frozen koji back to warmpth to create more spores, rather than risk this whole thing, whaddyathink?
If in doubt, throw it out. =( It's better to have to start over than risk making yourself or someone else sick.
Anyway, thanks again.
I made a culture of both colours in seperate sealed containers of steamed rice and the green one seems to be pretty viable and closer to the 'ideal' (the spores it's producing are about the right colour, the mycelia tried to form a clump, etc.), but as it's a wild strain, i'm a little hesitant to use it in a brewing.
Short of sending a sample to the CSIRO for analysis, how can i get a positive ID for this?
Thank you kindly.
attempt to make Koji-kin today. The cold
mountain brand is just not in Florida. Wish
me luck.
I live in Wasilla. I was wondering if I could see your operation and talk to you about making koji and/or malt rice. I will be coming to Anchorage on Sat. if that would work. This is a great site with lots of info although I am still a little confused.
Thanks
So this time, to avoid rotten rice-tane-koji, I just froze the shaker that had the tane-koji, until I was ready to use it. Worked like a charm!
Natch~!
This is my problem. i only have Aspergillus oryzae cultived like colonies on a inclined essay tube in the laboratory and in my country (Chile) don't sell the koji's spores. i put some colonies on a broth of malt extract to activate and proliferate the Aspegillus, and then i spray this broth on the rice to inoculate, simulating the addition of koji's spores that you do in your guide. At 24 hour later, the 50% rice grains begin to color itself with a green-mint color (inside the grain, not outside) and at 48 hours is almost all of that color. Along this 2 days, the rice smells like nuts with a sweet touch. this is alright? What you recommend to do?
exist some way to send you a photo of this?
I found your webpage 6 weeks ago when I was on my search for koji making to make miso. Your site is the only one that is most impressive, and the only one shows how to reproduced the Koji spores. A few months ago I started to make tempeh and learned how to reproduce the spores, and your technique is so similar. I have been successfully making many batches of Koji rice and wheat since. I like to share my experience with your reader, especially those who has not have much success in making koji. The first batch I made with long grain white rice, it came out good, but I was not too impressed. The next batch I used organic short grain brown rice, it came out perfect, but when I put some on a plastice container to let the spores mature, it did not turn out as green as I hope, but I was able to use it for my next batch. I cooled the rest of the koji rice and left refridged in plastic bag, a week later I took it out to use, to my surprise, lots of the grains look light green. I Picked out those grains and let it dry, and used in my next batch. Since then I have made many more batches of Koji seeds. My routine is to washed soaked brown rice or wheat for 4-6 hrs, drain 1-2 hrs, steam in cheese cloth 1 hr, take the rice out of the steamer in the cloth and placed in a baking pan, let it cool down then springkled spores on it and mix it a few time, then twisted the cloth to make it into a ball, sprayed with filtered water, and placed into a large salad bowl. I mixed it up every 12 hrs, and moisted with spraying water each time( I also used 2 in/out temperature gages, it's a must). I spread it out on a baking tray when it getting too hot(104 or higher), also turn the lamp off at this time, but kept the cloth on until I see some greens. I used the oven and an adjustable lamp, I also placed a large bowl of water on the bottom of the oven. This weekend I made koji with the malted wheat I got at the brewery, and it turns out to be the best so far. I's very sweet, and already has green dust by 36 hrs. I let it dry in my cupboard until I get back from my work next week, then I'll mix it with some lightly roasted rice powder, and grind it into powder in the coffee grinder ( this is the technique I used for my Tempeh spores.)
Just want to let you know how much I appreciated your works and your webpage. And if has not been for you, I wouldn't have a life time supply of koji spores:).
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