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Learn to read the coffee roast with your senses



Look, Smell, and Listen, So you need to learn to read the roast with your senses, as most roasters have done throughout history.


The principles are simple: look, smell, and listen. For the looking part, you will need some sample beans, already roasted to the color you prefer, to which you compare the color of your own beans as they roast and gradually deepen in color.


You place these sample beans where you can see them easily during the roasting session. After you begin the roasting process, nothing dramatic will happen for some three to ten minutes (or even longer in the case of convection ovens) while a grassy or burlaplike odor rises from the beans.


You needn't watch the beans during this early stage of the roast, but if you do you will notice that they are changing in color from a gray green to a light golden brown.


The exceptions are decaffeinated and aged coffees, which start out a lightish brown and gradually darken. In some cases your observations also may be confused by the thin, light-colored skin that covers some beans, called silverskin before roasting and chaff after.


When you are monitoring roast color, ignore these large flakes, which will remain a light brown color regardless of how dark the rest of the bean becomes. Eventually steam, still smelling like grass or burlap, will begin rising from the beans. Gradually this steam will darken and take on a coffeelike odor.


On the heels of the appearance of the darker, coffee- smelling roasting smoke you will hear a subdued crackling sound, confirming the onset of pyrolysis, or the inner transformation of the bean. From this moment forward you must depend mainly on sight.


Assuming your goal is a medium to medium-dark roast, wait about thirty seconds to a minute after the crackling sets in and begin peeking at the beans to monitor their color.


How soon after the onset of pyrolysis you need to start your visual inspection of the beans depends partly on how dark you want to roast, and partly on the roasting method you're using. Roasts develop rather quickly in hot-air com poppers and very slowly in convection ovens, with stove-top and gas-oven roasting ranged somewhere between.


With dark roasts your ear and nose may offer additional assistance. As coffee passes from a medium roast to the slightly darker roast usually called full city, the roasting smoke increases in volume and subtly changes in odor, while the crackling sound, which tends to diminish or stop altogether during the middle ranges of roast color, starts to intensify again. This "second crack," together with the fuller, more pungent roasting smoke, can be a reliable indicator to an experienced home roaster that the time is approaching to conclude a dark roast.


Regardless of whether you are pursuing a lighter or darker roast you will need to observe the beans visually as they approach the critical moment when they match the color of your sample. When they are about the same or a little lighter than your sample you must stop the roast and begin the cooling process, usually by dumping the roasting beans into a colander or bowl.


I realize that "the same or a little lighter" is hardly precise language, but you'll leam. Whichever roasting method you use or roast style you prefer, you will eventually develop a feel for timing through experience with your particular method and equipment.


Again, only our general unfamiliarity with roasting technique makes these instructions any more intimidating than directions for broiling a steak or preparing eggs over easy.


An obvious warning: Never leave roasting beans unattended. This is a particularly important caution with the stove-top and hot-air- popper methods. With these approaches you should not even leave the room until the heat is off and the session over.


If coffee beans are abandoned inside a hot roasting chamber long enough, they become semiflammable not nearly as dangerous as many foods become when left over heat, but flammable nevertheless.The gas-oven and convection methods allow you a bit more lee- way. keeping a few simple records, it is possible to determine approximately when to end a roasting session by elapsed time, thus permitting the use of a kitchen timer to alert you to the impending moment of truth.


By Kenneth Davids

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