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I Wanna Make Home-brew Shoyu. Am I Nuts?

Every now and then, I get the urge to do something out of the ordinary...sometimes WAY out of the ordinary. The latest urge is to make shoyu (soy sauce) at home. I know the basic ingredients (soy beans, wheat, salt, water) and *general* brewing methods, but nothing about quantities or ratios or temperatures. Do I absolutely need Aspergillus mold? Anybody got any wisdom or advice for me?

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  1. Wisdom says not to bother, but it does sound like an interesting experiment. If you do try it I would say do everything in your power to make it as precisely and as close to the real way as possible. Otherwise, why bother if you know from the start that you're going to produce an inferior product.

    2 Replies
    1. re: HaagenDazs

      That's kind of my problem, tho...I don't know what the "real way" is, in terms of recipes. I know I should start with equal parts soy beans and wheat, steam the mixture, and add salt and water...but how much salt? How much water? Do I let the mash sit until it tastes like shoyu? Can it really be that simple?

      1. re: ricepad

        Oh gosh - I don't have a clue. I've seen some food programs here and there that show how it's made but I've never paid attention enough to really know how it's done.

        I did a little Google search and found this which would be of ENORMOUS help to you:


        One key here is the use of the hot sun to help ferment and age the sauce. In other words, if you want to do it now is the time to plan for summer.

    2. I would toss this up with home made phyllo, more effort than it's worth, with the end product being not necessarily what you wanted.

      Out of curiousity, what recipe are you using?

        1. I'd say you're nuts, but gotta love your determination. For me, even if the recipe worked out, just can't ever imagine myself saying "that was some damn good shoyu". Let us know how it turned out.

          1. Ricepad, Go for it!

            This from someone who's been stone-grinding everything for the past year, so take it with a grain of ....something.

            I will add my observation from stone-grinding soaked soybeans though. During one of the times when I was making soymilk I happened to save a small jar of the soy mixture/foam from the step in the soymilk making just prior to straining. So, this is the light foam on the top of the kettle , from stone-ground soy cooked for a while in water. I put it in a glass jar, covered it, and it stayed in the refridgerator for maybe 1 week or two? I forgot about it. When i came upon the jar, I opened it and wow, what a beautiful fragrance! Just totally delicious smelling!

            At that time i didn't do anything with it because I wasn't thinking. I have a feeling I'll come back to it the next time I make soymilk. Maybe I will be relying on your shoyu making wisdom then.

            1. I am so interested..Please keep us posted. I am allergic to wheat. I have found the wheat free shoyu but really miss having different thicknesses and tastes - I used to keep 4 different soys in the house. I bet, I could use the process and ferment with something other than wheat.. never thought about it before but that is very exciting. Please let us know how it works. If I try I will as well.

              1. Yes, definitely. Kikoman, etc. have perfected the process during the last 1,000 years or so. better to re-invent the wheel.

                1 Reply
                1. re: Joebob

                  kikkoman makes a lot of soy.........but hardly the best

                2. Yes, you're nuts. Don't do it... my mom used to make soy sauce (but this was normal in Korea back in those days and everyone did it) and the stench it created was too much. The fermentation takes a long time - several weeks or months, if I remember correctly. She kept it in a giant ceramic pot out on the balcony but when the temperature wasn't ideal, she would have to bring it indoors (that was really too much). Even when outside, the smell was so strong that we could still smell it in the house. Perhaps a smaller batch would create less odor but really, you may get complaints from your neighbors.

                  Now, the Korean way may be slightly different from the traditional Japanese method. My mom used dry fermented soy bean blocks ("meju") and would pour water over them and add a huge amount of salt. As far as I know, those were the only ingredients. The whole mess would ferment and stink up the neighborhood. The resulting solids are miso and liquid is soy sauce. But you probably already knew that.

                  Anyway, even starting with meju the whole process took weeks. I have to assume that starting with soy beans would take longer.

                  1. Well, I tried it, and I'm fairly pleased with the results. Unfortunately, I tend to be rather sloppy in memorializing things, so I have no photos and sparse notes.

                    I started with a pound of dried soy beans (from an organic health food store). I simmered the soy beans for three hours, then drained them and let them cool. Then I mashed them up a bit, and realized I should have cooked them longer. The beans were softened, but not really mashable. I mixed a cup of AP flour into the semi-mashed beans, then formed the mixture into a log. I sliced the log into about 1" slices, and arranged them on a big paper plate covered with a tea towel. I set the plate on top of the fridge to get nice and moldy.

                    In the meantime, I filled a gallon jar with chlorine-free water, and added salt until it tasted just salty enough...I think it took about a cup of Diamond kosher salt, more or less.

                    After 12 days, the soy/flour slices had grown a nice layer of white, green, and black mold. At this point, had I not seen a few pictures online of similar growths, I would have tossed them! Instead, I put them in the brine jar, covered it with plastic wrap, and set it outside to ferment. The jar was in the shade, but received indirect sunlight all summer long, where temperatures would hit over 100F for several days at a time. At least two or three times a week, I would swirl the contents of the jar.

                    Finally, after about 6 months, I brought the jar inside to harvest my shoyu. I lined a sieve with a coffee filter and set it over a bowl, then ladled the brew into it, straining out the chunkies. Let's face it...the dregs looked awful...like I was emptying an overused diaper. The liquid, however, is heavenly. It has a very complex flavor, and my daughter says it's kind of tangy.

                    It wasn't a whole lot of work, but it did take a long time. I'll try it again this spring, but next time, I'll cook the beans longer, and document the process better.

                    2 Replies
                    1. re: ricepad

                      Wow, you are hard core. Thanks so much for the final report!

                      1. re: ricepad

                        You were mentioning that the beans were not soft enough after 3 hours of boling.

                        Did you try soaking the beans overnight before boiling - this is a technique used in making tofu (bean curd).

                        Also did you drain the beans before mashing? Do you put the drained water in the sauce mixture?

                      2. i have been making soy sauce at home for the last 5 years. if you are really interested, i can show you the whole process.

                        1 Reply
                        1. re: david soh

                          Ya im embarking on a miso making quest, and during my reaserch found out that the drawn off liquid from the miso is called "tamari" and that shoyu is made with a specific kind of aspergillus. I admire your bravery. Ive tried growing Koji in my oven with a light instead of the soybean\ flour route, but ive failed that miserabally (partly due to the fact that i dont have a koji starter, only frozen kome koji). I too would like to hear all about it david soh.

                        2. I sure hope you do this and share it with us. I love these kind of projects. David soh, please
                          share your experience with us too. I think I remember a book by William Shurtliff about
                          making Miso which had some info about the production of Soy Sauce.

                          1. You need Aspergillis Oryzae mold spores.
                            Ricapad is mad as a snake ...Relying on invasion of dangerous wild molds along with unwanted yeasts and nasty bacteria is foolish and injurious to your health.
                            You need an incubator to grow the aspergillus on rice to make koji to start with. Altenatively you can purchase dried koji. Make sure you follow careful hygeine and sterilise all containers and utensils to avoid dangerous bugs and the toxins they produce.
                            30 years experience making Miso and Shoyu in small home quantities