Coffee Roasting
(or how to
put us out of business!)
There have been many small coffee roasters start-ups in recent
years. Many of those doing the roasting “graduated” from home roasting
to commercial roasting. There are many advantages to home roasting. You
can have fresh roasted coffee all the time. You can roast coffee to
light, medium, or dark or anything in between that suits you. You can
buy a great many strains of Arabica beans from businesses that sell
green beans to home roasters. Compare that amount of choice with the
already stale coffee, from unknown sources, in grocery stores.
There are many home roasting machines for sale that you can choose from. Here are two methods of roasting coffee: Drum
roasting heats coffee beans that are inside a rotating drum. The drum
has fins inside it that cause the beans to tumble as the drum turns.
Fluid
roasting bounces the coffee beans on a column of hot air. Both methods
keep turning the beans so that the beans roast evenly. Fluid roasters
and drum roasters debate about which method is better.
Ideally
your roaster provides you with lots of good information and functions:
elapsed time of the roast; clear view of the roasting beans and their
colour changes; the temperature of the beans (not just the space in
which they are roasting); quiet operation so hearing first crack and
second crack are clear; the suppression of smoke from the roast; the
collection of chaff from the roast; rapid transition from roasting the
beans to cooling the beans preventing beans from over roasting; a
profile of the roast that is a record so you can improve your “recipe”
for the particular beans you just roasted. There is no
ideal roaster that provides all these advantages!
As a roaster you
can keep good records to use in improving profiles and improving
roasts. A bright LED flashlight often facilitates seeing the changing
colour of the beans. A kitchen timer can count up the minutes and
seconds of the roast. Some home roasters add thermometers to their
roasters. Coffee roasting uses high temperatures and fire is a danger.
Never leave a roast alone; for safety’s sake always stay with your
machine. Eyes, ears, and nose provide information to the roaster. And
the more information the roaster has the more he or she can improve and
shape the roast. The roaster starting with high quality beans will
quickly improve on the stale and bland coffees on the grocery store
shelves. Your fresh roasts will be vastly superior to stale coffee.
As
coffee roasts, the beans expand, lose weight and get lighter in colour
until the beans reach their “yellow time”, the beans’ lightest colour.
Then the colour changes to sand, then tan, then light brown, then
darker shades of brown, to black in very dark roasts. At some point in
the roast the beans go through first crack that sounds like popping
popcorn. Water is exploding out of the beans in first crack. After
first crack you have a drinkable coffee. It goes from a light roast to
a medium roast and then in second crack a dark roast. Second crack is
faster, quieter, and higher pitched than first crack. It sounds a bit
like milk being poured on rice cereal. The farther the roast goes into
second crack the darker the
roast gets and beyond second crack the beans can catch fire. The darker
the roast, the more diminished the flavours in the roasted beans. Many
coffee connoisseurs prefer light and medium coffees for the sake of the
flavours. However, if you prefer dark roasts, there are strains of
green coffee that are best dark roasted and will give you rich,
complex flavours. As a roaster you choose the roast levels that please
you and the strains of green coffee that please you. My knowledge
of home roasting machines is out of date. To see the home roasters
currently available go to Sweet Marias website www.sweetmarias.com and
click on “roasting”. Before we go any further Home Coffee Roasting:
Romance & Revival (revised edition) by Kenneth Davids is a must
read. None of the home roasters he mentions are current; but, the
explanation of the process is excellent background understanding needed
to hone your roasting skills. You will learn what is happening in first
crack and second crack and learn about roast levels.
POPCORN AIR POPPER |

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We recommend that you start roasting with a popcorn
air popper. Our first roaster was an air popper. The air popper you
need has a popping chamber (or in our case a coffee roasting chamber)
with a solid base and vents along the sides to agitate the coffee
beans. See the photos below. Use as much green coffee as you would
popcorn kernels -- trying to roast a lot is a mistake. You will find
instructions online for roasting coffee this way. As with any online
instructions, be wary of the quality of instruction which will vary
from poor to excellent.
Initially the beans are heavy and a
wooden spoon is helpful for agitating them to get an even roast. As the
beans become drier and lighter during the roasting process, they will
agitate well without being stirred. The wooden spoon is also useful to
lift out a few beans several times during the roasting process to check
the colour. Every popcorn popper is different and you need to figure
out what works for you. The chaff from the roasting beans flies
everywhere; but, in our roughly finished garage it is just a matter of
sweeping up after the roast. If you roast inside you will need a way to
exhaust smoke like a vent over a range. Once the beans are
roasted they need to be cooled quickly, or they continue to roast past
the level you want. We use two large-screened colanders and a fan
outside and pour the beans from one colander to the other in front of
the fan to cool the beans. With this operation the chaff also flies
away. If you have a stiff breeze you do not need a fan. However, the
fan is more predictable. From start to finish the roasting
takes six to eight minutes and then you add the time for cooling the
beans. The last time I checked in a large hardware store’s kitchen
section I found a popcorn popper with the right kind of popping chamber
for $20 Canadian. If you decide that coffee roasting is not for you
your investment is small and you can still pop popcorn. There are
roasters who install a thermometer in their popper and never advance to
any other roaster. We recommend this simple, easily learned roasting
method.
View from the top of a hot
air popcorn popper with the proper design for roasting coffee.
(click image to enlarge) |
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