## 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 % increase Soak % 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.