I had a kilogram of Roasted Barley (European) left over after the summer. Seeing as it was already milled, I decided to spend the dollar fifty and replace it with some unmilled malt in the fall. My friend had mentioned keeping it for darkening beers from cold steeping. Rather than do this, I decided to try making a hot grain beverage. Now, you make tea with tea leaves, coffee with coffee, so I figured it should be called a roasted barley.
I have some small tea infusers for when I use loose leaf tea and make just a cup. They are the size of a very large acorn (smaller than most tea balls). I filled the tip as full as I could with roasted barley and put it in some boiled water. I swirled it around to help extract faster, and once I felt that the resulting brew was dark enough, pulled the infuser and washed it out.
Here it is in my insulated clear cup so you can see the color. It turned out quite dark, very similar to a dark drip coffee.
The taste from steeping a small tea infuser worth of roasted barley for a few minutes was pretty mild and pleasant. I'd liken it to a weak drip coffee without all the tastelessness. My wife and I prefer it to commercial grain drinks such as Caro and Inka when they are brewed black. All told, a pleasant drink and worth trying.