So I did some digging and there are a few people working with this stuff to do a mock dry age. It can also be used to cure charcuterie style with drying times reduced by multiples of at least 3 or 4.
My understanding is that freshly cultured koji is best, but takes some equipment to do so. In lieu, I bought some koji cultured rice on Amazon and intend to start playing around with it this weekend. I'll try to post a few of my exploits here.
Anyone else on bowsite crazy like me and experimented with this stuff? Care to share some insights? On the flipside if I disappear you'll know the China mold done got me...
elk yinzer's Link
Here's a link to that F&S article.
Thawed out some prime backstrap from a doe I killed in October. Gave it a heavy dusting of the koji flour, and left it on a rack, uncovered, in the fridge. Temp is 37 degrees.
Internet instructions say you want to let it “age” for 2 days, 3 max, or it dries out too much. I’ll cook this thing up Sunday night which should be about 54 hours, splitting the difference. Meant to do a before/after weigh-in, but forgot. Next time.
An issue here, unfortunately I’ve never actually had a dry-aged steak. On the bucket list but just haven’t got to it. So my point of comparison will be a “normal” backstrap.
Planning a bresaola-type cured product with a top round, that I will get started here when I have some time.
I’ve been doing some more reading on this stuff and people have reported good results using koji as a fish marinade also, so have lots of walleye and salmon to experiment with as well.
Aged the backstrap in the refrigerator for a total of 56 hours. It was beginning to dry out and get a crust around the edges, don’t think I would have wanted to let it go another day.
I checked on the odor throughout the process and it was a slightly funky, earthy, meaty, mushroomy, parmesan sort of smell. Not totally off-putting, but wasn’t incredibly complex or appetizing either.
Rinsed off the koji which was mostly a paste-like consistency and patted the meat dry. Seasoned with some olive oil, salt, and pepper to keep things simple. Grilled over high heat, as per my usual, until internal temp hit 125 and let it rest for 10 minutes then sliced thin for serving. One of the things I commonly read about this process is that it browned or charred the meat a lot faster, which was definitely the case. The grill marks took to it really quickly, and there was a nice browned crust over the whole piece.
The texture, in my opinion, there was definitely some improvement there. Backstrap cooked this way doesn’t hurt for tenderness, but this was almost fork tender. Even the ends which cook fastest, and by logic would have absorbed the most koji through the muscle fibers, were really tender.
The taste was a bit more complex with some of those deep, earthy undertones, but it wasn’t quite as intense as I expected. That may have just been a function of under-salting it somewhat, as I wanted to pick up any flavors the koji imparted. More salt might coax out some of those savory elements.
More to follow, just getting started with this stuff.