How much involvement do you want?
Some people just have a bit of the chemist in them.
They like to mix and stir, whir and measure. Roasters
vary along this dimension. Some simple stove top models
are basically just a sauce pan with a tight lid and a special
The handle contains a crank that allows the roaster to
stir up the beans during the process. Stirring is essential
to keep the beans from burning on the bottom as well
as to keep the hot air inside circulating evenly.
Even in this simple set up, be sure to look for ones that
have a thermometer in the lid. Temperature control is
important for proper roasting.
At the other extreme are roasters that do it all for you. Pop in a pre-determined volume of green beans from a
bag, close the lid and walk away for a few minutes.
These deluxe models have inbuilt thermometers, thermostatically controlled heating mechanisms, clever
air-flow control geometry and rotating canisters and a timer to automatically shut off the device at the proper
At the upper end of the price range, these rocket ship roasters do everything but eliminate the smoke that
invariably accompanies the process.
How effectively do they heat and circulate air?
The most common type are air roasters that work more or less like a popcorn popper. Hot air is circulated
throughout the mixture, while the beans are agitated. This gives a uniform roast and some models can even
filter out the chaff produced as the skins burst from the expansion of the bean.
Most allow you to watch the process through a glass exterior, to judge the degree of desired roast. Frequently
they have pre-set amounts on the dial ranging from light to dark.
The ability to circulate air evenly and heat uniformly is critical and designs vary in the degree to which they
meet these goals. For example, a roaster with a heating source only at the bottom and constricted air flow is
going to provide an uneven roast.
Drum roasters help overcome this problem, by providing a rotating drum that uses gravity to move the beans
around, rather than relying solely on a stirrer at the bottom.
Beware, though. Many don't have windows for observing the roasting process - a must for those who like to
experiment and fine-tune the roast. And, not surprisingly, with the greater quantity of bean comes a larger
volume of smoke. Be prepared to ventilate well.
Once confined to more professional use, home devices are now readily available and have the added benefit of
being able to roast larger quantities. Useful for those large dinner parties where you want the freshest possible
coffee. And who doesn't want that?