Foaming Moromi!

It has now been 3 days since completing Sandan Shikomi and fermentation in progressing a little too well.  When choosing the correct size fermentation container, you will need one that is at least 3-5 times the volume you plan to make.  For example, use a 30+ litres fermentation bucket to make 12 litres of sake, or in my case a 60 - 120 litre fermenter for 24 litres of sake.

There is good reason for this as you need to allow for the expanding foam produced during the early stages of Moromi.

Below is my 60 litre fermentation bucket, which due to large amounts of carbon dioxide being produced blew the lid of the bucket during the night, brew temperature was 11.4°C.  There is normally a little more room for the foam, however I have placed a 5 litre bottle of frozen water in the fermentation bucket to help lower the temperature.

Foaming like this tells us that the fermentation temperature is too high and must be reduced.  I am now trying to reduce and maintain between 7-10°C until primary fermentation is complete.

Arrival of my Tane-Koji Grains (Koji Kin)

Friday morning saw the arrival of a small package containing some Tane Koji formed on grains of rice, used by commercial sake brewers to distribute koji kin spores.

In comparison to my homemade Tane-Koji, these ones are dark green and heavily laden.  I am looking forward to making my next batch of koji rice.

Below is the picture of my attempt at making Tane Koji for comparison.

Starting the Sokujomoto.

On the Sake!

Finally I have a batch of sake underway and today marks the Sokujomoto day 2.
My yeast of choice is the Wyeast Sake #9, pictured below.

Also known as the Kumamoto yeast, after the Kumamoto Prefecture, it was the Brewing Society of Japan who gave it the designation Yeast #9.

This yeast can make an aromatic and clean gingo-shu, with a full fermentation that is well suited to low temperatures.  The fruity aromas produced are similar to apples or melon.

Further information on the history behind the Kumamoto yeast can be found on John Gauntner's blog.









After adding the Miyamizu style water, 88% lactic acid, yeast, koji and rice the temperature was 17.1°C.  This is where the aquarium thermometer comes in handy, after making koji it can be cleaned steralised and inserted in the fermentation bucket to accurately monitor the core temperature of the Sokujomoto and then the Moromi.  The alarms can be set for 1°C above and below the target temperature. 

This is the Sokujomoto just after the rice addition.

24 hours later, the Moto was maintaining 15°C, the rice absorbed water and the yeast completed their lag phase.  When I came to stir the Moto, it already had a nice sweet aroma and was starting to bubble.

I will now keep the Moto as close to 15°C as I can for the next 4 days.

6th day of the Sokujomoto.

The Moto is now generating a lot of foam which must be knocked down twice each day.

 After knocking the foam back the Moto has a nice thick milky appearance and has a taste similar to yoghurt, tangy with a sharp bitterness.

The Sokujomoto after stirring and just before the start of Sandan Shikomi, with the Hatsuzoe addition.

Final Update, 6kg batch of Kome Koji finished at 48hrs

After 6 hours of repeated cooling, my batch of Kome-Koji is finally finished, cooled, bagged in weights for the Shubo, Hatsuzoe, Nakazoe and Tomezoe.  I have frozen all the fresh Kome-Koji with a small test sample re-hydrating in water.

Next, time to make sake.

Update, 6kg batch of Kome Koji - Incubation time now 39 hours.

Upon waking this morning at 5am then again at 7:45am, I was greeted with a strong sweet chestnut honey type aroma.  The Koji were heating up again and needed to be cooled.  I turned off the heat mat as this was no longer required.  I spread out the Koji, still covered in cloth, to create an even heat distribution and aid cooling.

By 36 hours the Koji smelt very pleasant, were generating lots of heat and had good coverage as pictured below.

Kome-Koji spread out in the incubator and generating 39.2°C

The Aquarium Thermometer accurately measures the temperature of the Koji.

 

Good coverage of Koji mould, but still needs a few more hours until ready.

Update, 6kg batch of Kome Koji - Incubation time now 26 hours.

It has now been just over 26 hours since I inoculated the 6kg of steamed rice.  There has no been much to report until now.  At 20 hours the Koji have started to produce their own heat and there is a slight aroma of Koji.

With the temperature reaching 39.2°C, I unwrapped the bundle and cooled the Koji to 32.5°C before wrapping it back up and returning to the incubator.

@ 26hrs temperature is starting to climb and reached 39.7°C

Most of the rice grains have visible mould on, which over the next 22 hrs should increase.

All I have left is to check the temperature and get my head down for a few hours.

Update on Kome Koji batch using Tane Koji

Making my own Tane-Koji has been very interesting and I have learned a lot about Koji thanks to the information shared by others who have made their own.  

The benefits of making your own Tane-Koji would be cost, however a lot of work and effort goes into further incubation and drying out the Koji so that spores are released with maximum yield.  

I learned that trying to use Koji that were still damp only achieve a low yield of spores, so a further 36 hours of drying at 35°C has now dried them out.

On a positive note, the Kome-Koji is coming along nicely and there is a fair coverage of mould growing.  The smell is very pleasant and I hope that further testing will produce good results.

The Kome-Koji rice as it starts to develop spores.  All grains have a good covering of Koji.

Magnification showing Koji growth.

 I have now started to dry out the Kome-Koji to induce spore production, which will be my closing update for this trial.

Although making your own Tane-Koji is cheaper, I still think that purchasing the spores from Vision Brewing, Akita Konno, or any other supplier is good value for money, and they have worked hard to make the spores available to people worldwide and supporting them is important.

Last night I undertook the mammoth task of steaming 5kg of rice to make a new batch of Kome-Koji, to be used in my first batch of sake.  To make this possible I purchased two steamers, which will just about steam 1.8kg of rice per tier.  I have used a 10g pouch of spores from Vision Brewing which should be sufficient.
More to come on this later....

One of my Russell Hobbs steamers purchased from Homebase at a bargain price of £19.99

I am slowly starting to add details of all the equipment I use and where they can be purchased in the UK, which can be found on the Ingredients and Equipment page.