This is what I've been using to draft the coffee roasting book I've been working on. It's a hard cover Moleskine book that came in a swag bag from some event. Between the hard cover and the strap, I can fit it in my pocket without worrying about it getting destroyed and I can write notes as I think of them no matter where I am. The contents get moved to a computer, organized, and fleshed out when I have larger time blocks and I'm in the right state of mind for working on that.
In case any of you wanted to know what infrared gas burners looks like, here's a picture. My larger roaster has two of these running down the length of the drum. They're considerably less polluting than the more common atmospheric burners, but you need to read farther ahead on your roasting plan because it takes a while between changing the burner setting and seeing the impact of that change.
Author of Typica software for coffee roasters.