My first CR-120 wouldn’t get out of its own way . . . like another reviewer here’s second machine it could run all day and not get past a City roast. So, after several friendly phone calls I trucked on down to Brightway (conveniently only 30 miles away) to exchange it. Steve was already set up to test the replacement . . . sitting on the cold warehouse floor next to a slightly open roll-up it did (or failed to do) more or less the same thing. Third try was the charm . . . up on the workbench it clearly wouldn't "smoke" the beans in the maybe 50 degree warehouse, but it gave a decent Full City with their "Colombian" bean in 13 minutes, with line voltage indicating between 115 and 119. I brought it home, and working in a 65-70 degree kitchen two test batches gave the following results:
Batch size 150 grams . . . very close to one of their measuring cups full to level.
Line voltage irregular, but mostly between 113 and 116 Volts for the duration of each roast.
1) Brazil Mogiani Bourbon, nicely even roast, to "Vienna" . . . light oil, 235 c. bean temp (by IR thermometer), in 10 minutes 45 seconds. Very little chaff . . .
2) Nicaragua SHG Segovia, nicely even roast, to "Full City" . . . no oil, 230 c. bean temp (by IR thermometer), in 11 minutes 30 seconds. Lots of chaff . . .
The CR-120 has no internal temperature compensation and, because it is targeting a (relatively) long roast time to maximize coffee “body”, is running right on the edge of producing enough heat. It is sensitive to line voltage variation and to ambient temperature, far more so than, for example, the internally compensated (but no longer in production) Hearthware Precision. This is not an "outdoors" or "in the garage" machine in cold weather . . . not, at least, without some form of (externally applied) thermal compensation. And the chaff filter is too small, and seems easily clogged . . . (although I can't for sure say it has any demonstrable effect on the roast). Cooldown is very fast (unlike the Hearthware, which seems to continue roasting a bit after you press “cool”), and it’s a good thing since it would be difficult to remove the hot chaff filter and dump the hot beans for faster external cooling. You cannot depend on the timer to give consistent batch-to-batch results . . . just set it “long” and watch for your desired endpoint (and I do mean “watch” . . . the fan is loud and second crack is hard to hear). It sure worked great for the coffees mentioned above, though, and everything I’ve tried since, and I look forward to using it with a wide range of, especially low chaff dry processed, beans. I’ve had no problem with “smoke” (possibly a result of the low heat and even roast), and simply turn the machine to blow out an opened window over the kitchen counter (but then I tend to stop short of burning off the coffee flavors that led me to home roasting in the first place).
Several little notes: you won’t really need a scale . . . use the provided measuring cup, level full (just like you fill your porta-filter); the “protection device” (fuse) hardwired onto the heater unit is like your appendix . . . it serves no useful function but can kill the machine . . . (so much for “intelligent design”); to open (disassemble) the unit you will need a T10 (torx) screwdriver . . . don’t bother (unless you’re as nuts as I am), there’s not much you can do inside it anyway (e-mail me if you want details on what you might want to try if roasting in colder conditions) and it’s easy to strip the threads in the otherwise sturdy resin body when re-assembling; to “observe” the beans with an IR thermometer (I used a Raytek Mini Temp MT-4, $70 from http://www.officeshops.com/) you have to open the lid . . . no minor thing since it will blow chaff all over and, by dumping heat, somewhat slow the roast. I was very pleased, though, to see numbers that conformed very well (almost exactly) to those reported by Sivetz and Davids.
I have, and all in all I'm very happy with, both a HWP and a Rosto (which together cost less than and can roast more than the wretched Alpenrost which they replaced). Because of batch size considerations and despite the very slightly greater "ease of use" I expect that I'll use the HWP mostly for "feeling out" new beans and where I want the smaller quantity (85-100 gram), and the Rosto for more regular use, especially for fuller bodied darker roasts (although lighter roasts are done quite nicely in the Rosto too). All said, the batch size and the solid construction of its simple and straightforward design, and the real “bottom line” of an even and well balanced roast, makes the Caffe Rosto, despite its shortcomings, my favorite among the four different roasters I have owned.