Andrew Tridgell, who built this coffee roaster a.k.a. chocolate truffle melter, gave us Samba and Rsync.
Ok now that it's hooked up to a computer, how about using a genetic algorithm to find the perfect roasting settings? (As a bonus it could evolve over time to match your gradually changing tastes.)
As a home coffee roaster myself (including building my own roaster) I'm guessing that experimenting programatically with roast times would cause the smoke alarm to go off regularly.
I guess you could hope that later generations get better at this, but there's always the risk of a 5 alarm mutation ;-)
Hook up a smoke detector to turn off the roaster. If smoke doesn't clear in 1 minute, have it shoot off a fire extinguisher. Problem solved.