Making Homemade Soy Sauce

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Making Homemade Soy Sauce

(Photo Attributed to Author: Melissa Doroquez)

Most of the Asian ethnic cuisines have soy sauce as a major seasoning ingredient in them. And while you can buy, in almost any cosmopolitan city, excellent soy sauces, making homemade soy sauce is fun and rewarding.

You can not only achieve bragging rights to your other cooking enthusiast friends, you can customize the soy sauce to your particular tastes and culinary preferences.

So I thought doing an article on making homemade soy sauce would be of benefit for our readers. After all, we are people who enjoy taking new trips, finding, cooking, and tasting foods from ethnic cultures the world over. And we also enjoy making our own sauces, and learning how to reproduce favorite condiments, spices, sauces, etc., from cultures all around the planet. So, with that being said and out of the way, let’s now get into what is involved in:

Making Homemade Soy Sauce

The ingredients you will need are a very short list. However, for the best results when making homemade soy sauce,
Organic Soybeans

Organic Soybeans

you must carefully select only the finest quality of each ingredient-

  • SoybeansSelect only top quality, organically grown soybeans. You absolutely do not want any chemicals, preservatives, or impurities in your soybeans. Also, organic soybeans will have a much more stable level of protein in them. It is the proteins breaking down in the fermenting process that gives the sauce its complexity.

(Photo Attributed to Author: Shree Krishna Dhital)

Wheat (Photo Attributed to Author: Shree Krishna Dhital)

  • Wheat Flour – Select only the best quality, organically grown whole wheat flour. Wheat is what will add the touch of sweetness to you sauce, and the carbohydrates in wheat are what will enhance the complex aroma of the
    Rice Flour (Photo Attributed to Author: Ocomejessian)

    Rice Flour (Photo Attributed to Author: Ocomejessian)

    finished product.

  • Rice Flour – again, only top quality, organically grown and produced Rice Flour will do. Rice flour will also add to the complex aromatic bouquet, flavor, and color of your finished sauce.

  • Salt – Again, quality is King. Use Himalayan crystal salt, or fine quality sea salt, freshly ground. These salts are rich in nutrients and minerals. They not only enhance the flavor of your sauce, they add to its healthiness for you.
Making Homemade Soy Sauce

Himalayan Crystal Salt (Photo Attributed to Author: Poyraz 72)

Fine and Coarse Sea Salt (Photo Attributed to Author: Romain Bréget)

Fine and Coarse Sea Salt (Photo Attributed to Author: Romain Bréget)


  • Water – 100% pure, clean, fresh water. Distilled water is good to use, or, even better if you can get it, is certified pure natural spring or artesian water – because of the healthy minerals it contains.

Those 5 basic ingredients are all you will need. The amounts of each should be kept proportionate with the following:

  • 16 oz. soybeans
  • 6 oz. wheat flour
  • 6 oz. rice flour
  • 8 oz. salt for the initial mash-making, plus more during the final, pressing and finishing steps
  • 1 gallon water

If you want to make a larger batch, simply hold to those proportions and you will be fine.

You will also need the following tools:

  • some flat, woven, stackable bamboo trays
  • a pressure cooker
  • Ideally, a large baked clay ceramic earthen jar, for fermenting – but if you don’t have that and can’t find one, you can use commercially produced fermentation jars. If using a traditional earthen jar, you will need cheesecloth and a bamboo lid, if using a commercially made fermentation jar, they should come with a fitted screw-on lid.
  • If you live in a dry, arid region, you may need a humidifier to create the necessary humidity for the aspergillus oryzae mold to form.
  • If you live in a cool region, or a region that has cool seasons, you may need a space heater to maintain the necessary very warm temperature needed year round.

Now on to the instructions …


There are 10 essential steps in making homemade soy sauce the traditional way. Get ready for a marathon – albeit a pleasant and rewarding one – because the entire process will take two years or more. The ten steps are as follows:

  1. Clean the beans in pure fresh water, soak them and steam them. Do not use tap water, unless you have a water purifier installed in your home. The water you soak your beans in should be pure and clean. Soak them overnight, at least 12 hours. The next day steam them until fully tenderized and “mashable” in a pressure cooker.
  2. Add the rice and wheat flours. This step is vitally important – in a suitably sized large mixing bowl, mash the tenderized beans into a pulp. Then add and stir in the flours until thoroughly blended together with the mash. Again, it will be the fermentation of these rice and wheat starches that will play a significant role in developing the rich, deep color. They also create the subtle sweetness, and the marvelously complex aromatic bouquet of your soy sauce.
  3. Now grow the aspergillus oryzae mold. This step is also critical, and essential. You must have mold, or there simply will not be any soy sauce made. And this step has to be executed correctly and with precision – otherwise all of your efforts in making homemade soy sauce will produce a finished product that is inferior. Spread the bean and flour mash mixture out on flat woven bamboo trays. You want woven, not solid, trays, so the mixture will breath better. Stack the trays in a warm and humid room or space and let them sit for 48 hours. Temperature is critical, and fickle – you want to maintain a temperature of no lower than 30 degrees Celsius (86 degrees Fahrenheit) and no higher than 31C (88F). The mash will develop a soft, downy white mold. This aspergillus oryzae mold is essential for the mash to ferment and develop its intense flavor.
  4. Add the brine (salt). The salty flavor of soy sauce is not produced by the fermentation. Adding salt is a fundamental and essential component of making homemade soy sauce. The brine also assists in the fermentation and, very importantly, it acts as a preservative, inhibiting bacterial growth. Again using a suitably sized large mixing bowl or vessel, stir and work the brine into the moldy mash until thoroughly blended together.
  5. Pack the mash and prepare to age it. Stuff the moldy, brine-infused soybean mash mixture into your fermentation vessel. If using an earthen jar, place a double layer of cheesecloth over the top, and the bamboo lid to cap it. If using a commercially made fermentation jar, just screw the lid on loosely – loose enough to allow a little air in, but not so loose insects can get in.
  6. Store in a warm place and let it age for a full year. If you live in a tropical or at least rather warm, year-round region, you can store the vessel outside. The cheesecloth will keep insects out, and the bamboo lid will prevent rain from getting in – the loosely screwed-on lid of the fermenting jar will do the same things. If you live in a cooler and/or seasonal region, you should store the vessel indoors, and keep them warm at all times. The mash will undergo a very slow fermentation, and you do want to stir it now and then – every 2 to 3 weeks is good.
  7. Separate the liquid from the mash. After a year the mash will have a dark brown color and by now it will smell like soy sauce. You may have to improvise with this step, unless you have a food press. What I do is take the mash out of the fermenting vessel, place it in a cloth bag, and tie the bag firmly shut tight. Put the bag in a very large, wide bottomed bowl. Now take a solid, flat object (A wooden board, just the right size to fit inside the bowl works great) and press down on the bag with all your might. Keep pressing until all of the clear, dark brown liquid has oozed and seeped out of the bag and into the bowl. When you think you have extracted all the liquid, remove the bag from the bowl and pour the liquid into another bowl. Then put the bag back into the first bowl, and repeat the pressing procedure. You may have to do this several times before you get absolutely all the precious liquid out of the mash. By the way, if you are an organic gardener, this mash can be reserved and used as fertilizer or a component in a compost. In Asia it is often used as animal feed, too.
  8. Now add more brine. The liquid at this stage will not be as salty as good soy sauce should be, so you need to add more at this point. And this step is where you can adjust the finished product to your tastes. “Light” soy sauce is usually about 16% brine, while the darker, heavier sauces are somewhere around 20% brine.
  9. Age the liquid some more. The liquid you have at this point is not yet true soy sauce that is ready for consumption. It needs to continue fermenting. And this is another step where you can adjust your process of making homemade soy sauce to your personal tastes. Place the liquid back into the (freshly cleaned out) fermentation vessel and let it age and ferment for at least six more months. A year is better, and two years is even better. The longer it ages and ferments the richer, darker, and more sumptuous it will be. It will reduce in volume over time, so if you are going for the most rich and full tasting, longer aged soy sauce, the trade off will be that you wind up with a bit less finished product.
  10. Bottle your soy sauce! After a minimum of 18 months of your time and effort, and possibly as much as up to three whole years, your soy sauce is ready to be bottled. Your experience of making homemade soy sauce has come to its rewarding conclusion … enjoy!

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10 thoughts on “Making Homemade Soy Sauce

  1. This is a very well written, thorough, informative and entertaining post. However, given how easy it is to just buy (for just a few dollars, at local Asian market stores) really good soy sauces of all kinds … I will pass on all the work involved in making my own, lol.

  2. Well done article, I must say. I am Korean, and my family has made soy sauce for many generations. Your presentation accurate good, and tradition does use the earthen jars. These jars are handed down from generation to generation and the older they become, is considered most better for producing finest soy sauces.

    • Min Jun, thank you so much for the kind endorsement! And I can imagine that an earthen jar that is many decades old, having been used to ferment generations of batches of soy sauce, would surely have aged and developed a unique patina and impart a special flavor to the soy sauce than a brand new, never used jar.

  3. This sounds like fun! It is a long, involved process, but really each step isn’t all that hard sounding. Just have to do a lot of waiting. Good stuff to know, Marv – thanks for this!

  4. I think making homemade soy sauce would be very rewarding. Appreciate this excellent resource of an article, dude!

    I have a pressure cooker, humidifier and space heater already, too. Just get me some bamboo trays and one of those fermenting jars, and I’m good to go!

  5. Very thorough and interesting post. I’m not sure I would have the patience to go through the entire process, but understanding how it’s done is good to know. Well done, and thank you.

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