Soy Sauce Koji Spores

(54 customer reviews)

From: 6,00

The amount refers to how much wet substrate can be inoculated. For more info, click here.


This is a strain for soy sauce with strong protease activity. It is meant for long-term, dark shoyus. If you want to make a light shoyu, A. Sojae is better suited.

According to the producers, this strain takes three days to fully grow on the substrate (soy beans and wheat). In my experience, the koji is finished after 40 hours.

We have a tutorial on how to make soy sauce, check it out here if you haven’t seen it yet.

Weight1,05 g

For 5 kg, For 50 kg, For 200 kg

54 reviews for Soy Sauce Koji Spores

  1. Annette Vollmer (verified owner)

  2. Stefan Weigert (verified owner)

  3. Dario Marxer (verified owner)

  4. Rob B (verified owner)

  5. Guido Bauhammer (verified owner)

  6. Dre (verified owner)

    These spores work like a charm. Used it on a mix of soybeans and rye. After 14 hours it really took off and started producing a lot of heat. Stir en vent frequently and make a thin mat! Full mold coverage, started sporulating at around 40 hours, so it was brine-o-clock! Curious how the moromi and shoyu will turn out.

  7. Adria (verified owner)

    What an interesting and well explained article.
I want to buy spores for 50kg. What weight of soy and wheat should I use? Since I understand that 50kg is when the soybeans are already boiled, right? How many liters of sauce can be produced?
    Another question. I have wooden barrels where wine has been made. Can I use them? Or should I burn them inside to eliminate the rest of the wine?
    Thank you very much for your attention.

  8. Gerhard Dragschitz (verified owner)

  9. Bianca (verified owner)

  10. Aleksandr (verified owner)

    All is great. Already started a soy sauce batch!

  11. Ricardo Sousa (verified owner)

  12. Lukas Schedel (verified owner)

    Top Qualität !
    Sporen funktionieren einwandfrei habe mittlerweile verschiedenste Garum sowie Sojasaucen hergestellt alle sehr angenehm würzig einfach Unamie;)

  13. Jérémy Godard (verified owner)

  14. Evgeny Zolotarev (verified owner)

  15. Moritz Lenz (verified owner)

  16. Michael Primes (verified owner)

  17. Guillermo Revenga (verified owner)

  18. Xenia Blanco (verified owner)

  19. Xenia Blanco (verified owner)

  20. M.M. Janssen (verified owner)

    Very lively spores and keep an eye on temps, these go like crazy. Received order within a few days.

  21. M.M. Janssen (verified owner)

    Very lively spores and keep an eye on temps, these go like crazy. Received order within a few days.

  22. Roberto Martinetti (verified owner)

  23. M.M. Janssen

    Very good supplier. Received within a couple of days, very good quality highly active spores (the “Soy Sauce” variant).

    This mold grows very fast, keep an eye on the temperature every second hour or so. I started of with the mash in the fridge with a heating element set at 28C, after 12-16h or thereabouts the temperature in the fridge rose to over 30C and temperature in the bean mash rose to 35C. After stirring and letting the fridge vent for a while I put them back. I had to let the door of the fridge open a bit to prevent the koji from overheating and sporulating. Ready after ~40h- (or at least, I think so. Completely covered in white and just a few tiny yellow/greenish spots from sporulating). Outside temperature ~4-8C

  24. Mamboline (verified owner)

    I have found the product on 7Hauben. Excellent quality, very good results.

  25. David Baird (verified owner)

    Quick postage, I have yet to use them, but I have used their products in the past and they have been extremely good!

  26. Petri Kautonen (verified owner)

    very good product. grew rapidly. just the right size package for home use. fast delivery even to Finland. I am very satisfied with the customer service and the product.

  27. Joshua Vd jagt (verified owner)

    Works great also with low temperature in the room with a great white mold growing and fermentation with going to a temperature of 25 /27,c .
    greetings from the netherlands

  28. Ludwig Ringbom (verified owner)

  29. Dennis (verified owner)

  30. fabio morresi (verified owner)

  31. Erik Arnemo (verified owner)

    I only just started my first batch of soy with these spores but it smells promising.
    In your toutorial, you said that they can overheat allmost from the start, I havn’t notised that yet.

    /Erik Arnemo

  32. Lukas Schedel (verified owner)

  33. Elena Garavelli (verified owner)

  34. Gabriel Batista (verified owner)

  35. ilaria Zappi (verified owner)

  36. Bruce Rennie (verified owner)

    concentrated, great quality spores. My version of soy using local organic kidney beans is firing away on all cylinders. Lovely personal vibe to the company, quick efficient delivery.

  37. ANDREA MOLINATTI (verified owner)

  38. Michael Falkensteiner (verified owner)

  39. Raphaël Gétaz (verified owner)

  40. Askan Worms (verified owner)

  41. Joanna Mulvaney (verified owner)

    Worked really well I was surprised how much faster and better the Koji grew than vision Koji. Will buy my spores here from now on. I used a Pyrex dish, damp tea towels with cling film on a seedling mat set to 32 degrees C. 18 hours to needing to be broken up and stirred then took off the cling film and seedling mat, stirred every 12 hours until 45 hours for sporukation just starting on the edges. Nice fragrance.

  42. fabio morresi (verified owner)

    the starter is arrived very fast and after two days he begin is job very well, now is a fragrant moromì, :-)

  43. Askan Worms (verified owner)

    Ich orderte ein Pack und dieser Sporen und bin begeistert. Die Sporen wachsen nicht nur gut auf Soja sondern auch auf Linsen und Cashewkernen recht gut. Man sollte wissen was man macht unddie Temperaturen vergleichsweise niedrig halten( 27°C). Ist die Temperatur zu hoch verlieren viele Eiweissfermente viel an ihrem tiefen Aromen.

  44. Eric Morris (verified owner)

  45. Johannes Selmayer (verified owner)

  46. Walter (verified owner)

    These spores worked quite well and the Shoyu-moromi I made with them already tastes great. Only 4 stars because of the relatively high price.

  47. Maria Elena Cantos Soto (verified owner)

    I have not tried this product yet, but I can talk about the previous ones: I am extremely happy with . They delivery even internationally fast, the prices are extremely competitive and the variety and explanation of spores great for their use. So far, all the cultures have worked as expected and are amazing!!
    I am looking forward to see more recipes in the blog. All in all, I have and I will strongly recommend

    • Viktor

      Thanks a lot for your comment Maria, we’re very happy to read that you were so happy with our products and service :)

  48. Anna Williams (verified owner)

  49. Judith Ebert (verified owner)

    Followed instructions on blog and in Sandor Katz book. Worked very well

  50. Bernd Simons

    We used one bag for ca. 12 kg and mixed it with starch before we put it on our wheat and beans mixture. After five days we had lot´s of koji spores and a fine fermentation, temperaturs below 30° celsius. Now after six weeks in the brine we have a brown very good looking, and salty raw soy sauce, looking forward what to come! :-)

  51. Enrico Bufarini (verified owner)

    Great product like all the oder spores that I bought. I follow Viktor’s instructions and they work very well. I used a redpine wood tray and incubated the Koji at 30 C for 2 days and the smell of mixed pine wood and Koji was awesome.
    I’m very happy with the shop: professional staff, very good products and fast dispatch.

  52. David A (verified owner)

    Perfect for making soy sauce! The spores are of superb quality and grow very reliably, yielding full coverage of the substrate. As noted in the tutorial, this koji grows vigorously and produces much more heat than ‘usual’ koji, so be sure to stick a thermometer right into it and monitor it frequently. And I can recommend to make the mat very thin to help the heat dissipate.

  53. Casper (verified owner)

    My compliments on the great service! Used 1 bag to inoculate about 5 kilo’s of soy + wheat substrate for soy sauce making. Read about the high-risk of overheating for this strain, and decided to take the easier route of fermenting it at room temperature for a longer time, since I don’t have a precise temperature-controlled fermentation room and would have otherwise used the oven. Mycelium growth was clearly visible within 12 hours, but otherwise growth was pretty erratic, sometimes heating up to 37 degrees, sometimes remaining at room temperature for a long time. First signs of sporulation were visible after 6 days, and then stopped by steeping in brine. Any comments are welcome! Overall it was a great experience and brought a lovely aroma into the house :-)

  54. Alex (verified owner)

    This grows very, very quickly, as the page notes. Be prepared to check on it every 8-12h. It needs frequent supervision so it does not sporulate or overheat. If you can do that, it grows very well.

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