Among these factors are origin of the beans, reliable vendor for green beans who'll offer you beans at a reasonable age and of high quality shown (clean of detritus and as uniform as possible in shape and size). From this point, you need to experiment with the temperature of the roast and length of roasting time and both are impacted by the roasting method or machinery. Home roasters will soon discover that an experienced roaster becomes both artist and scientist as they plumb the roads to the perfectly roasted beans.

While the more famous chains like Dunkin' Donuts or McDonald's or Coffee Bean and Tea Leaf may not be ready to release information about their signature roasting and blending recipes, they may be forthcoming about the origin of the bean (or beans) they use in their signature recipes. It never hurts to ask if you've found a blend you'd like to replicate at home.

Experiment first with single bean sources from Columbia, Costa Rica, Guatemala, Sumatra/Indonesia, Yemen or Ethiopia, for example, and learn which country's beans please you most. Don't be surprised if a combination of two or three beans produces the best cup for a balance of flavor, fragrance, and body. The next experiment can be fiddling with the type of roast from mild to full city roast to heavy-duty French/Italian dark roasts. For pure clean coffee taste, opt for the city roasts rather than the darker ones for more complexity and true coffee taste without any burnt or bitter edge.

As for length of time and temperature, so much depends on how you are roasting the beans, whether you're pan roasting or using a completely automatic or semi-automatic roaster that we can only suggest "follow the manufacturer's guidelines." For a surefire education resource, check out your local community college or extension catalogs for summer courses on home roasting, or ask your favorite coffee vendor if he/she ever does any roast-and-show for enthusiasts like you. Remember, roasting coffees is not as straightforward as brewing roasted beans, it takes a lot of trial and error. Where the beans are grown, how they're processed (wet or dry method) and how they're cleaned and prepped of debris can make each batch taste different even when the beans are roasted the same length of time and temperature.

In general, coffee roasting can take as little as five minutes or up to eighteen minutes per batch with home roasting equipment and you're most likely to observe the sound of the first crack between 10 and 11 minutes; roasting slightly longer at a reduced temperature will release the volatile oils surfacing the beans, a desirable quality in dark roasts. The key is knowing when/how your roaster will achieve the interaction between reducing sugars and amino acids (sometimes referred to as the Maillard reaction) to indicate the browning of the green bean. For Italian or darkest roasts it's probably best to aim no higher than 450-63°F. which requires close attention by you to determine the second crack.

Automatic home roasters vary in the type of heat used. Roasters can use heat conduction or radiant and/or convective heat, air roasting or pure convection. And, using the fry pan over a gas flame is an easier-to-control heating source than electric heating elements which cannot be "read" as easily as a flickering gas flame. Reading the manufacturer's manual will help explain this further.

As romantic as it might be to roast then grind and brew your daily cup, some roasted coffees require a "resting period" of a few days to a week to mellow. The benefit of this time will show itself in a better flavor in the cup. If your freshly roasted coffee isn't absolutely wonderful, give it a rest then grind and brew after a few days to see what the difference in taste is; the waiting may actually improve it.

Maintaining your equipment is also an important factor to a clean taste in the cup. Burner jets should be cleaned regularly for optimal operation and the most reliable timing. Most important of all, have fun with the home roasting technique. You cannot be a veteran roaster with finely honed instincts for detecting the cracking of the beans, the release of the aromatic oils, the evolution from raw green to rich roasted perfection in minutes. Roasting is an ongoing learning experience, so enjoy every moment of it.

Thanks to Kevin Vangorder for suggesting this topic.