Anything I’m Fermenting

February 10, 2012

Sake: The Mother of All Ferments, pt 1

Filed under: Brewing,Sake — iwouldntlivethere @ 8:53 pm
Tags: , , , , ,

I’ve never really liked sake. The stuff served at sushi joints and even izakaya type places around here always seemed insipid – drinkable, but not worth searching out. Then somebody got me to go to a tour/tasting at the new Ontario Spring Water Sake Company‘s Izumi sake brewery nearby. The sake they make blew my mind – I really, really liked it. I guess all it takes to be a good sake is being a freshly made, unpasteurized, 100% rice sake made in small batches by expert sake brewers! If you can get your hands on some, you should.

Of course, this being me, I now had to try making some myself. Turns out it’s not that easy, but not impossible. What’s really intriguing about sake is that it can involve three fermentations – one by koji mold to create amylase enzymes to break down the starch in rice to simple sugars, one by lactic acid bacteria to slightly acidify the mash, and one by yeast to make the alcohol. Beyond this the cool thing about the yeast ferment is that it happens on the grain, as the enzymes from the koji break down the rice, so the yeast is fed a steady amount of sugar over the period of the fermentation. This allows the yeast to ferment to much higher alcohol levels than found in other fermented drinks, without distillation.

From various sources, it seems to be accepted that the main objective in sake making is to minimize flavour. The main flavour components of finished sake come from the koji mold, plus a little from the yeast. The regular practice is to use highly milled (polished) white rice – the more milled, the less flavour, the better. The yeast ferment is kept fairly cold to prevent much flavour creation (like in lagers), and even the lactic acid bacteria’s contributions are negated by the common practice of using refined lactic acid to acidify the mash.

I guess this is why the mass-market sakes I had were not appealing, as they use further practices to reduce the flavour like carbon filtering (Zima, anyone?), diluting and adding alcohol, etc. Even some of the high-end sakes I’ve since tried have been very uninspiring because they didn’t taste like much. However, there seems to be a happy zone achieved by some sake brewers where off-flavours are reduced, but there still remain enough other flavours to make the sake interesting and enjoyable.

The sake brewing method I’m using is based on the instructions found on Bob Taylor’s excellent website Taylor-MadeAK – Brewing Sake, and the insights (and koji spores) gained from Home Brew Sake. Rather than repeat what they’ve already written about, I’ll just note my variations. As with all my posts on this blog, my main objective to to record my thoughts and processes for myself in the future, and secondarily for anybody from the public to learn something.

Step 1: Make Koji

1.1 Rinse, soak, drain, then steam 5 cups short-grain white rice (3.5 for koji, 1.5 for the moto):

Rinsing rice half-way

This is after about ten changes of water

Rinsing Rice end

This is after at least 20 changes of water; you can just about see the rice now

I gave up rinsing after about half an hour of continuously rinsing and changing the water. The water was still cloudy at this point, but there was no end in sight, so maybe starch from the actual rice grains was washing into the water.. In any case, the rice turned out fine, so I’m not concerned.

The rice soaked for 2.5 hours (this includes the half hour of rinsing) – this is about the time I found I needed based on earlier trials with this type of rice (Shirakiku Brand Calrose rice). It drained for another couple hours (we went for dinner), and I steamed it for 45 minutes in a steamer lined with a piece of leftover mesh material from the bag I use for brewing (‘voile’ curtain sheer fabric). I have this fabric on hand, and the rice doesn’t stick to it.

Rice loaded into steamer, lined with voile fabric square

1.2 Innoculating the rice

After steaming the rice for koji was cooled on a cookie sheet, then loaded into a large ziplock bag (the rice for the moto went into the fridge). I had made a batch of koji previously that I let go to spore, rather than use for sake. This is the source of spores for the koji (the original spores come from Home Brew Sake). To inoculate, I punched a lot of holes in the lid of a mason jar with a nail and hammer – this is very effective because the holes made sharp little points on the inside of the lid, which abrade the rice/spore/koji mixture and help release the spores. When I’m not using the koji-kin, I put a paper coffee filter over the lid to allow the koji-kin to stay dry and fresh, but not escape.

Inside the lid

The perforations are quite sharp!

Koji Kin in Jar

The jar is covered with the filter seen in the background when not in use.

To actually get the spores onto the rice, I lay the ziplock bag of rice on its side and put the koji-kin jar’s mouth into the bag, then close the zipper of the bag as tightly as I can around the mouth of the jar. Then I invert the jar over the rice and shake it up and down for a bit. When I see a layer of spores on the rice I remove the jar and close the zipper fully, then mix the rice up inside the bag. The rice is then dumped onto the cookie sheet again, and fully mixed by hand.

Repeat the process once more – the rice should look a bit green from the spores. Try not to let air into and out of the bag when you are shaking the jar as this releases the spores from the bag before they’ve had a chance to stick to the rice.

1.3 Incubating the koji

The inoculated rice must be kept in a warm, humid environment. As per Bob Taylor’s instructions, I made an incubator out of a cooler, with some minor modifications. For a heat source I used a cable heater meant for reptiles – it’s cheap, readily available, doesn’t need to be modified (no thermostat), has a safety margin in that it doesn’t heat beyond 50C, and is waterproof. The instructions say not to use it near water (likely for liability issues if the silicone coating has been scratched by, say, an iguana), but during my first koji attempt, the cable was under a centimeter of water for many days with no problems. For this time, I’m using a different configuration to keep the cable off the bottom of the cooler where condensation collects – better safe than sorry. But in any case, it can easily handle the damp and condensation inside the cooler.

(NOTE: This method – using a ziplock bag – DID NOT WORK. The koji over-heated, see Sake pt 2.] Also, the rice is in the same ziplock bag I used to innoculate it as it can be folded over, but still open to the air (see photo). In my first attempt at koji I found that condensation would drip off the top of my cooler and onto the rice, making little spots of infection on the surface. The bag will prevent this. Like Bob Taylor, I use a temperature controller I have for brewing beer to keep the temperature around 96F.

Incubator loaded with koji

The temperature controller is to the right, its temp probe is inserted into the bag of rice in the cooler.

Here’s a photo of the incubator empty. The rectangular plastic container is to hold the bag of rice off the bottom of the cooler, and the small one holds water for humidification. The repti-heat cable is wrapped around the bottom half of the cooler, and is taped in place with aluminum vent tape (what I had on hand, I presume it is heat and damp proof).

Empty Incubator


  1. Did they have Zip Lock bags when the process was discovered? The answer is nope use food grad plastic as a last resort, I would suggest glazed clay, wood or glass. Spores yeast and all the good stuff move by air movement your closed system provides neither.

    Comment by Desan — August 13, 2013 @ 3:31 am | Reply

    • Point taken, though using some plastic is one of the most minor changes in this system as compared to how sake making was done when it was discovered (e.g. sanitation, electric heat, cultured pure strain domesticated mold and yeast, clean water, highly polished rice, etc!)

      Comment by iwouldntlivethere — August 13, 2013 @ 9:17 pm | Reply

  2. Although I would not employ a ziplock bag, I am not hesitant to use food grade fermentation buckets for the primary fermentation on the bean meal must.
    I stir air into my must every day for the first week, and once a week thereafter until I am prepared to separate the bean must from the sauce and age in a glass carboy.
    Aging in glass, anareobicaly, allows extended flavoring and darkening over periods of months. I use dried pineapple and pineapple rind, chillies, orange rind, black pepper, even toasted oak.
    For me, treating this process as a blend of traditional Japanese/Chinese/korean soy sauce production and western wine making techniques yields outstanding sauces with incredibly layered, nuanced and balanced flavors with amazing depth and mouth feel.

    Comment by Anakritis — January 5, 2014 @ 6:27 pm | Reply

    • Actually this was meant for another thread… Sorry!
      I’ll try to pay attention to what tab I click next time.

      Comment by Anakritis — January 5, 2014 @ 6:30 pm | Reply

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