I mostly use light or medium roasts from Colombia or Guatemala, But I've started experimenting with some dark roasts for my cold brew. I have wanted to go around to my local roasters to try and find the best beans close to me, but laziness means I mostly get bulk from the local grocery store. I have a slow drip cold brew tower that use to try and keep cold brew available all the time with. I haven't been to successful to achieve a consistant brew each time, but I need to start tracking my measurement to experiment and find the best ratio. If I am in the mood for a hot cup, I use a single serve french-press/thermos. This was actually a gift and I was pretty skeptical, but I'll have ended up using it almost daily, makes a perfect cup and keeps the coffee hot for longer than I've ever needed. Cream, no sugar.