At about this time last year I got the idea of trying rye for koji making. I had my grain farmer run the rye grains through the husking machine he uses for barley. It worked fine, so I made 3 batches of rye miso. The first one, a 6 month miso, was good and now long eaten up. The second, a 1 year miso is now open and it is great. It has a flavor of it’s own.
There is a 2 year miso too, to open next year.
In the mean time I must get busy and make more rye koji and rye miso.
It grew very well
I’ll make some with the other barley tane koji too – and a couple batches of 2 year rye miso.
timogarden 
Thanks for your answers! I’m new to miso making and it’s hard to find information on the internet. I have another question: How often should I mix it if I am going to ferment at room temperature (23 C)? Also it is okay to ferment in a metal pot? I think it’s stainless steel.
For growing koji, 23 degrees has worked for me but try for a bit warmer. Growing at 23 will take more time, like a day or 2 more. Mix in air (and check) every 12 hours.
Good luck!
A metal pot might work (not aluminum), but it doesn’t breath and hold moisture like wood or terracotta. You should be able to find a terracotta baking pot or similar.
Also, can you make miso with wheatberries?
I have never tried as far as I remember, but I’m sure it would work, especially if put through a husking machine in order to polish it slightly. I must try soon.
What do you do if your miso ends up too wet?
No problem. Most of the liquid rises to the top. You can drain it off and use it as a tamari soy sauce, and the rest as miso.