Anyone here mess with Koji? Started looking into it. This peaked my interest:

The primary enzymes in koji are amylase (it breaks down sugar), protease (it converts proteins into the amino acids) and lipase (it breaks fat into the fatty acids and alcohols).

Also, if you use alpha enzymes most are derived from Koji.


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  • edited April 8

    Koji is to eastern spirits as malted barley is to western spirits.

    It’s not the alpha amylase that makes it special, that wouldn’t result in fermentable sugars. It’s the glucoamylase, that can do double duty to result in fermentables, in many cases directly from starch without needing to cook it extensively. In fact a close relative to koji, aspergillius niger, is the primary source of the gluco enzyme many of us use.

    Everything else it creates, both positive and negative flavors, just comes along with the ride. Yeah, there are differences in koji strains and families.

    IMHO, there is no magic in koji, well, it’s magic is the gluco. You can use it creatively, there is some marketing value for sure, and if you are producing spirits “in the style of”, it’s probably critical.

    Koji from spores is a little like malting your own grain, combined with propagating yeast from a slant. Not sure if that makes sense.

    But… You are still going to need yeast - like malt barley the koji brings the enzyme to the party, but not the booze.

    There are dozens of ways you might put this into practice with grain or other starches. Maximal flavor impact is requires steaming and inoculating an entire batch worth of grain, which might be prohibitively labor and space intensive.

  • This would be strictly for sochu with sweet potatoes and buckwheat. This is not a I'm doing everything with Koji kinda thing. I'm trying to find any info on the chemicals it makes besides the enzymes. It sounds like it makes some esters along with citric acid.

    Luckily a friend's wife is Japanese and has a lot of experience with it making miso and shoyu. Once I do some more research she's going to teach us how to get started with it.

  • The other thing to keep in mind, proteases will create more base aminos, and more aminos mean more heavier tails alcohols. If your goal is a broader array of esters, this will help create some of the more interesting alcohols.

  • This is a great video on making sake.


    Mad respect for this guy. Every artesenal distiller knows that felling of sweating your ass off and wondering what am I doing only to taste your product and be satisfied you have created something new.

  • Cool video.

    I thought sake was distilled rice wine? What that guy was making seemed to be was just the rice rice wine.

  • I am not going down this rabbit hole

    But if I were...

    Koji has a very traditional clean process. You do X, then Y, then Z. It is like that as each product it is used to make is expected to have a specific flavor profile. Chinese and Korean traditions are similar. For us as distillers, what interests me, it what and how we can effect our processes. There is no analogy in the eastern world (that I have found in my minimal research) for what we do in the western world. Meaning, the vast majority of koji processes are designed for a highly regimented and CLEAN flavor. It's not the same as whiskey and rum. Koji would not be needed for fruit based distillates.

    What's not interesting: Using koji in a traditional and clean manner, to effect the flavor in a minimal or very light way.

    What would be an interesting aspect: What would happen if I made it dirty? How do I use koji to blow up and completely change whiskey and rum to create more flavor? What is the chemistry of dirty koji? Has this ever been investigated? Would would be considered an off flavor in saki make positive flavor contributions to a distilled spirit? Think sour mash or dunder/muck. If the flavors are too strong in a distillate, would it make an interesting blending stock like high ester rum or peated scotch? The key to this would be understanding the chemistry of koji and the by products it may produce.

    You can see the traditions in the saki process to remove most "off" flavor. They polish the kernel to remove those parts that might contribute to flavor, to the point that it's mostly just the starch. For me I've not liked saki that much, it is the equivalent to vodka-esqe wine for me. I also wasn't raised on rice as much as a typical easterner, so that affect my palate too. I want see examples of folks in Asia that are doing non-traditional things with it. I know there is, but it's harder to find since it probably gets less press and is less likely to show up in English.

    Again: I am (probably) not going down this rabbit hole

    A koji person sent me this link: https://kojicon.org/

  • edited April 21

    It would be super interesting to see how the Koji enzymes work on a rum fermentation.

    Angel yellow label has some component of the aspergillis niger if I recall, there's a pretty epic thread on HD where they talk about a vomit like odor coming from the fermentation, I can only assume it's butyric acid... but I have no direct experience with the YL, so i can't comment.

    I remember hearing a podcast that Kris Koenig of Golden Beaver does a lot with rice, although i dont know if he's using a koji. i can't recall if I'm seen him here on SD, but I do believe he's on ADI... He may have some insight on the funkier flavors.

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