Despite the lack of evidence here, there’s been a lot going on in the kitchen. Among other projects, I’m preparing for my Kojicon presentation. The lineup this year is exceptional, so get your tickets now—if you’re a fan of this newsletter you’ll be in fermentation heaven for the two weeks of presentations, demos, and conversations. I don’t want to spill the beans (and rice, and corn, and vegetables, and bread, and vinegar, and more) too much ahead of time, but I did make something recently that’s worth talking about since we haven’t covered it here yet.
Broadly speaking, koji uses two kinds of enzymes to digest whatever it’s growing on. Protease breaks down proteins, turning large ones into small ones—and those small ones include amino acids, which our tongues understand as umami. This is the fundamental process behind miso, soy sauce, and garum from non-fish sources. Amylase breaks down starch, turning those long carbohydrates into short ones, a.k.a. sugars. Amazake, and by extension just about every kind of East Asian alcohol—from sake to baijiu—is fermented from sugar produced this way, usually from rice but other grains are common depending on the country and region.
If you try making amazake from white rice, you’ll be amazed at how sugary it gets. I made some as part of a class I gave to a restaurant crew a while back, and they couldn’t get over the sweetness. It’s like supermarket rice pudding—you could run it through an ice cream maker as is and get a delicious dessert. It’s an excellent illustration of why simple carbs like white rice have such a high glycemic index: they’re made of sugar.
This means that instead of buying sweeteners, we can use koji to unlock the sugars in grains and vegetables—and then use those sugars for all sorts of culinary adventures. I made some amazake recently using purple sweet potato and yellow beet, and used the bulk of it for something I’m going to discuss in my presentation. But I did take some of it and reduce it to a syrup, which is in the photo above. It’s sweet, and because of the high starch content, as it reduces it thickens into almost a pudding-like consistency.
It has potential as a dessert in this form—beets and sweet potatoes are both great with chocolate, for example. I’m also interested in trying it in baked goods, where it would add color, complexity, and soften the dough a bit. Think of the role sugar plays in zucchini bread, but where the sugar tastes like the vegetable in question. I’ve got something cool (and zero-waste) in the works on that front that I can write about soon.
There are lots of ways you can vary these ratios to achieve a variety of effects, but here’s a super-simple beginner formula:
1 part cooked rice (or other vegetable matter, like sweet potato or beets)
1 part koji rice
1 part water
Mix everything together, pack it into a jar, and hold it between 130˚-140˚F (60-65˚C) for 12-24 hours. As you close in on 24 it should be getting very sweet. Blend it into a smooth paste and use for all manner of baking enhancement. In this instance, I strained the liquid off the solids and then reduced it into the sticky caramel-type substance in the photo, reserving the solids as well for another use. The possibilities are infinite.
Give it a try! Amazake is simple, and an excellent introduction to koji fermentation (you should all buy Koji Alchemy if you haven’t yet, since it’s got loads of info and ideas about what to do with amazake).
Oooooh, I hadn't thought of making beet or sweet potato Amazake! I'm definitely going to try this! I am looking forward to your KojiCon presentation!
I recently started experimenting with growing koji, and sweet rice amazake was one of the first things I made. And indeed! I was amazed at how sugary it gets. Amazing amazake ;-). See you at Kojicon!