The Koji Files

There isn't a day that goes by where I don't see one or more posts on Instagram about Koji. My feed has suddenly become a visual gallery of mold. While certain repetitious posts usually steer me away, I can't help but become more and more intrigued by this mysterious ingredient.  

So, what's Koji? 

Koji, or Aspergillus oryzae is a mold that is responsible for the creation of soy sauce, sake, fermented black bean paste, rice vinegar, and the globally loved miso. If you ever get a chance to try amazake, pick up a bottle! Its almost like a drinkable rice pudding made with ferments rice and koji. It is said to have been domesticated atleast 2000 years ago and thrives in warm, humid environments. Koji is traditionally grown on rice, that is then added to different mixtures to continue in the fermentation process. Like all molds, they hold a magic that helps transform basic ingredients into nutritionally dense and umami rich products. 

You had me at Miso...

It was the spring of 2014 when I took a miso making class led by Mika and Nicholad Repening of Go-En Fermented Foods in Whitefield, Maine. At the time, they were in the process of perfecting their miso before officially producing and selling miso at the Brunswick Farmer's Market in the summer of 2016. I was quite excited to finally learn how to make miso, since for several years beforehand, I was too timid in my fermentation skills to try and pull off a 1 year ferment.

As the class went on, I realized the procedure was fairly simple and totally manageable on my own. As we finished jarring up our batch of miso, I took out my Sharpie and wrote the date. I drove it home, wrapped up in wool, and protected from any potential harm that could occur over along the 50 minute drive home.

Once in the kitchen, I tucked it up above my pantry where I could easily forget about it and allow the koji to do its thing. Every few months I checked out the jar and always noted very little change from that initial jarring other than the mixture darkening a bit over time as the tamari develops. 

Exactly a year later, I dusted off that quart jar, removed the top, scraped away the layer of salt,  and took my first taste. It was perfection.tasted just like it should. It was salty, subtly sweet, and its chunky texture reminded me of South River Miso products. Since this first batch, I have been making a few batches of miso every year, keeping enough around to last the year while the newest jar ferments. 

Miso is generally made from 3 ingredients, soybeans, sea salt, and koji. Although the beans can be altered and the type of salt can differ, koji is a key ingredient that makes all the magic happen. Koji or Aspergillus oryzae, culture that gets often gets inoculated onto rice and turned into 

I'll never forget enjoying slices of golden beets cured in layers of chunky chickpea miso. A fine fermenter himself, my homie Josh of Cellardoor Foodworks taught me a trick or two regarding the use of miso as a curing agent. Under refrigeration, sliced vegetables could be cured while essentially being buried in containers of miso. Although unseasoned, it appears he was in stride with these traditional pickled vegetables.

Koji Cures

At some point last year I came across the video below of Jeremy Umansky and after checking out his Instagram feed, saw koji in a new light. Instead of growing the aspergillus mold on rice, why not grow this mold on various animal proteins? This question has lead to koji cured meats, with flavors achieved similarly to dry-aged products but in much less time. This technique can certainly change the way meat is cured

Shio Koji ~ The Cultured Marinade

Just as I stumbled upon koji cured meats, shio koji jumped into my life via Google. A simple mixture of koji rice, water, and sea salt, the 2 week ferment takes on a sweet, sour, and salty taste, and is traditionally used as a marinade. 

It was this recipe that had me sprinting down into the root cellar, pulling a bag of koji rice out of storage, and immediately starting a batch. The sweet, earthy aroma developed a bit slow, but winter is a tough time to ferment here since the temperatures inside my home are so drastic. Once ready, I have a feeling I'll be marinating some of our autumn harvested pork for a few days before finishing it off on the grill. 

Moving Forward

If you watch the video above, you will just see how the use of koji is unfolding. Several chef's are taking koji to new heights by growing it on different mediums. Rather that the typical rice, it is transforming scallops, chicken, beef, wild game, and even vegetables into "aged" meats worthy of high end restaurant. 

While this technique seems a bit more complex then my typical miso creation, I do see it having a place in my kitchen and rotation of ingredients. Each year I hope to develop my skills and experiment with new ingredients and techniques. 

I feel grateful for the opportunity to come across new culinary avenues via the world of social media. If you are interested in learning more about koji, continue with this article