More Amazake, slightly modified.
Carafe was full to the top when I made this:
I started this night before last, using 1 rice-cup shortgrain brown sweet rice. Normal porridge water level for 1 rice-cup white rice is slightly more than 3 rice-cups normal sushi rice level, and based on some mental calculations involving the brown rice water level, I settled on 4 rice-cups brown rice water level. Added a pinch of salt, which is supposed to help break down the brown rice better and make it cook fluffier/more digestible.
After the rice cooker declared the porridge was done, I poured it all into the blender pitcher, then poured out most of the liquid. Then pulsing and then slowly increasing the speed and gradually adding back the liquid, thoroughly liquified it. If I was making rice milk, this would be the stage when I would strain out the bran, add sugar, sea salt, and sunflower or sufflower oil.
Instead, I poured it back into the rice cooker inner pot, checked that it had cooled to below 60°C, added some of it to about 1/3 to 1/2 cup of the previous batch of amazake (the one I had already flavored with a little sea salt and grated ginger), then stirred this into the pot. The idea was to see if a small amount of the previous batch could be used as starter for the next batch like yogurt.
In the mean time, I had been searching for the answer to maintaining the requisite 50~60°C incubation temperature. This led me to surfing various Japanese websites and blogs — of course they have a lot more options and sources for rice koji, including koji speciality shops, one dedicated to organic ingredients ...sigh.
But I did find out that the Iseso Miyako Rice Koji which I had bought on Amazon is the most popular brand that is readily available in Japan.... and in fact, Iseso also sells rice koji made with organic rice.
And I came across a blog entry that said her Zojirushi rice cooker maintained 60°C in “go to sleep” mode. (What the heck? Do I have anything like that on my approximately 1 decade older model?)
Luckily she posted a photo of the Japanese control panel, and it had the model number right on it. After more searching in the Zojirushi America website, where none of the models offered had the same number and none of the product photos were clear enough to read the control panels, I found a similar model and a pdf instruction manual.
It turned out that “extended keep warm” function on my rice cooker — which I had tried to obtain more info about earlier but had to give up because all the product descriptions and manuals only said, it keeps the rice at “ideal temperature for serving” without specifying what that temperature was (Besides which, it would not turn on when I tried to use it, and I though the function had become disabled on my old machine) — is the same as that “go to sleep” mode. I also found out that this function
does not operate when Brown Rice or Porridge is selected. Ah ha!
Well, after trial and error, because if the last cooking selection had been Brown Rice or Porridge, the selector remembers and stays on that setting and therefore will not initiate the “extended keep warm” — alarmed “bip-bip-bip-bip!!” Instead of smartly chirping “beep! beep!” — I was able to get it to accept the “extended keep warm” by setting it and starting it to cook regular sushi rice, then immediately hitting cancel, then pressing “keep warm”, WAITING FOR A MUNUTE OR TWO, then pressing “extended keep warm”.
Since the blog mentioned that some models push up to 65~70°C which would kill the koji, I used a dampened heavy flour sack towel to cover the inner pot and — another trick I noted in one of the blogs — using the rice cooker handle to keep the lid halfway open. I set things up this time so the instant read thermometer probe is left in the pot, and display could be easily read by just pressing a button to turn it back on. And for the most part, it maintained 57°C. I re-moistened the towel and stirred the contents when the temperature rose to 60-62°C.
10 hours later, in the morning, I decided it had developed some sweetness but weak — not sufficient starter? — and decided to add 25g of the other 200g of Myako Rice Koji and give it another 10 hours.
After the total of 20 hours incubation, I put the contents through the blender again, then strained into the storage carafe. Then warmed up a small amount — maybe 1/2 cup of rice milk and poured that into the blender pitcher to rinse down the sides, then added rice bran and rinsed the strainer into it, blended then strained into the crafe, thus recapturing some of the incubated sticky residue from the blender pitcher and the rice bran.
The resulting “pseudo Amazake” in the carafe was waterier than the first batch and last night when I tasted it still-warm, it didn’t seem very sweet, though the sweetness was there. I really wasn’t sure if it didn’t taste much more than slightly sweet brown rice milk.
But surprisingly, when I tasted it this morning after overnight in the refrigerator (it had separated into a layer of light yellowish liquid at top which I stirred back together), it was refreshingly and strongly sweet... but maybe a bit more “cultured” in the background aroma... to be honest, with my mold sensitivity, I could detect a “faint” mold origin — possibly it had entered the next “blooming stage” from the excessive incubation which if totaled for the original Amazake koji would be 4 hours plus the 20 hours, and if it counts, the slight warming I gave it. I tried it warmed as well as cold, and I kind of think I like it better cold in this case because I detected the mold-ness more when warmed. This might also be the problem hinted with using the previous batch Amazake as starter.
It could also be that for me adding grated ginger is a requirement and I’m used to the ginger negating this background flavor — I will have to try that next time I have some.
I think I will also try making another batch with same amount of shortgrain brown sweet rice, water and kosher salt, and this time using only the 25g Miyako rice koji and only 10-15 hours (one blogger said it took 15 hours incubation in winter time, and less than 5 hours in summer time).