Ok, heres my humble opinion on this issue. I always roast my single origin beans seperatley THEN blend the beans together post roast. Why? Although all greens will have a similar moisture content (+/-12%) there are other factors that effect how they will roast...meaning it is hard to do justice to each origin if you rost them as one lot. Bean hardness, sugar content, size.. (if you are not using beans screened to the same size) even the method the bean was processed will/can all impact on the roast process. In my opinion it is very difficult if not impossible for me to bring out the characteristics in each origin and then apply it to my espresso blend if I roast all the beans I use in the blend at the same time.
Ok- in saying this I see nothing wrong at all with a HOME roaster using a 250gm capacity home roast popper or Alpenrost combining all the greens together. My living is made from roasting...dawn till dusk (or is that dawn to dawn?? :grin: ). For a home roaster this is a love, a hobby...a second wife or hubby!!...but if you are roasting 4,5,6 origins individually to blend for an espresso you might suddenly find your significant other half is less supportive of your hobby.
. I believe roasting each origin seperately is the way to go- and that applies to homeroasters as well. Must note that Home roasters are very particular. ElPugDiablo is right- why take shortcuts if you are serious about your hobby.
