Sake pt 2: Fail!

Fail! Just want to report and discuss the failure of the koji batch.

I didn’t take photos, but after 12 hours the koji was looking great – starting to stick together, getting a good covering of white fuzz. Then… it flat-lined. The white fuzz disappeared, the rice just looked like boiled (n.b. – not steamed) rice; it smelled nice and koji-ish, but wasn’t sticking together. It just didn’t feel right. I gave it an extra two days, but nothing changed, so I composted it.

I wasn’t obsessively monitoring the temperature, but I did notice it go up to 103F once. However, my suspicion is that it over-heated. Unlike in Bob Taylor’s method, where the rice is spread out on a plastic tray, I tried using a ziplock bag. I believe that this reduced the surface area of the growing koji enough to enable it to create enough internal heat to cook itself. Also, there’s a photo on the Ontario Spring Water Sake Co’s homepage of a cake of koji – it isn’t very thick, maybe 1.25 inches. Considering the size of koji batches they make, where growing the koji in thicker cakes would save a lot of space, it must be important to them to keep the cakes thin. The over-heating hypothesis also explains why the koji failed after apparent success – it took the first 12 hours to build up enough cell mass to generate heat. Live and learn; good thing I have lots of koji-kin!

I’m trying again, but with the rice spread out in two plastic containers:

It's just two trays stacked on top of each other.

The lids are not closed, they don’t even fit well into the cooler, so there is a lot of air exchange. They’re mostly there to keep condensation off the rice.

Here’s the thickness of the rice (very fluffy at this point):

You’ll probably notice the brownish spots in the photo. I absentmindedly forgot to close the lid of the koji-kin jar when I was innoculating this batch, and about 20 g of koji-kin rice fell in. I just went with it and mixed it in and hope this is enough innoculant, and that nothing bad will happen.

I’ve also been thinking about the placement of the thermometer probe in the rice. My feeling is that putting it in the middle of the rice means that the outside could get pretty hot before the heat reaches the middle. However, once the koji is generating its own heat, if the probe is not in the middle, it will not be measuring the maximum temperature. Not sure what to do yet.

 

Sake: The Mother of All Ferments, pt 1

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):

This is after about ten changes of water

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.

The perforations are quite sharp!

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.

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).