another_jim wrote:If you need separate roast levels, you have to do separate roasts; no ifs ands or buts. Otherwise it depends on the roaster. If you have a drum roaster, SC/TO, HG/DB, or an air roaster you can slow down to take 4 or more minutes to get to 300F, there's no problem roasting any beans together. The trick is just to mix them about a week or more ahead so that the moisture equalizes.
If you roast in a fast airroaster, roughly speaking, roast the greenish ones and the yellow brownish ones separately.
In general, even colors at the end of the roast are not meaningful -- you are looking for even colors entering and exiting the first crack to judge roast uniformity. If you still have greens or yellow, as opposed to beige-brown ones entering, or anything lighter than middle brown ones exiting, you are going to have raw flavors in your final product.
Makes sense...i do as you suggest...I always mix my pre-roast 4-5 days ahead....
I wasn't aware that by an ultra slow ramp up as you suggest, I could possibly get decent composite roasters...already roast 'pre-blended espresso blends, such as Metropolis Redline, and SM's Monkey Blend and Donkey blend...the Redline will have slightly variable roast colors, which I figure is as it should be...as I like my espresso roasted slightly darker (30 seconds into 2nd crack..no oil, or just a few drops), it all seems to work pretty good...still, if anyone has 2 bean roast combo suggestions I'd love them...because of the volume requirements of the CO/UFO combo, 3 oz roasts ala poppers and such are not only impractical, but also downright horrible...thus combining is great, say 14oz total per load...otherwise 3-4 separate varietal roasts would yield way more finished roast (nearly 2 lbs after moisture loss) than I can get through before staling.
In some ways, Popper and other some volume roasters such as HotTop, Gene cafe are almost better suited to small volume espresso blending, if you don't mind doing 3-4 separate roasts. True "artisan" roasting, to be sure.
