Hi guys, i'm pretty new to home roasting so i'd like to pick your brains on how to reproduce a roast profile. So far i am getting the hang of my quest m3, today was my first try reproducing a profile i liked from a roasting session two days back. here are the profiles

drying/ramp/development
4:56 (47%)/3:57 (37%)/1:29 (14%) - 12.8% weight loss, drop temperature of 206.8degC (total roast time 10:24)

5:03 (49%)/3:45 (36%)/1:30 (14%) - 12.7% weight loss, drop temperature of 207.1degC (total roast time 10:18)
coffee in question is Guatemala El Aguajal, fully washed bourbon

i could upload the artisan graphs if preferred. my questions would be

1) how close would you have to be to consider your roast profile reproduced?
2) in your experience, which factors tend to matter most for reproducing a profile (drop temp, absolute timing of each phase, or percentage of roast time spent in each phase etc.)?

Thanks again for your valuable input (:

The short answer is that "close enough" depends on your own palate and preferences. In my own opinion, both timing (relative and absolute) and finish temperature are important if you are trying to mimic past successes. I would typically call it "close enough" if the finish temperature was within a few degrees of the past roast, and the various roast phases no more than +/- 15 seconds in duration. But the faster you roast, the tighter the margins of acceptable variance are.

This is one of the things that the Roastmaster iPad application handles very well -- if you record your past fan and gas settings and then select a past roast as a profiling target, it will prompt you with little reminders when you need to change each setting as you go along.

thanks for the input, Mark! i've been recording my fan and amperage settings in the notes sections of my profiles so i do a quick "revision" before i charge the next batch. i did munch a couple of beans after both roasts so i can tell that they are slightly different already. hopefully it won't be too far off when i cup tomorrow!

As long as the graphs are almost identical then I say your two roasts are basically the same. Each phase of the roast is increasingly more important. So its way more important to match crack to drop than charge til yellow. Drop temp within a degree or two at most is important, though some coffee are more forgiving than others. Weight loss is huge tell on how things went, so continue to measure that.