I've roasted several different types of rice so far, all with similar results. I will say that none of my rice looks exactly like what I've seen in genmaicha I've purchased, and I think that's more due to roasting techniques than to the rice itself.
Some of my experiences so far have been:
- Stovetop worked better than oven roasting
-Initially high temp to get started, then reduce heat to a medium to high-medium or the rice will burn
-I've used hard anozide nonstick and an iron skillet... both work but the nonstick gave the nicest browning
-Short grain and long grain seem to brown the same and taste the same
-Mixed long-grain wild with the dark grains mixed in will burn more easily than plain white rice... was very tasty but I had to watch it like a hawk during roasting
-Some of the grains of rice will "puff" similar to popcorn, which I find visually appealing in the finished product. and is also tasty to eat just after roasting
-If you want a really bold coffee-like taste, you want to roast your rice (or barley if you're doing mugicha) until it's on the verge of being scorched
-When you brew, alittle grain goes a long way... brews best for me if I use a tablespoon or two of medium-roast grain with a cup of boiling water in a larger ~ 6 cup decanter... let it steep until it starts to cool, then fill to the top with cool water and refrigerate until cold. The first infusion will be the strongest, and if too strong, just cut back on amount of grain the next time. Every time you pour a cup/glass out of the decanter, refill to the top with fresh water. I get at least 4 days of use with one batch of grains, and have continued it as long as 7 days with no deterioration. It gives lots of mileage!
Hope this helps...