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Coast Coffee has split the business into four major elements; growing, processing, roasting and then everything else (testing, packaging etc.). Roasting is the most exciting, but for most roasting professionals and coffee industry people the key to excellent coffee is the whole roasting process.
If it was time and effort measured, growing takes 1000 times the processing effort and processing takes 100 times the roasting effort!!
It is that basic algebra that makes us realise the intensity and concentration required for the relatively small amount of roasting time is enormous.
Simple in Theory?
Roasting is quite simple in theory, the beans must be heated, kept moving so they don't burn or roast unevenly and carefully cooled.
However, there are a number of parameters which must be considered and taken into account before, during and post roasting if you are to achieve a consistent roast each time.
Customers will not remain loyal if each time you roast their favourite blend differently, sometimes strong, sometimes mild but never the same, it'
s simply unacceptable.
Coffee that is not roasted long enough or hot enough to bring out the oil has a pasty, nutty, or even a bread-like flavour. On the other hand coffee roasted too long or at too high a temperature is thin-bodied, burned, and charcoal-flavoured. Coffee roasted too long at too low a temperature has a baked or muddy flavour.
The roaster has to consider a whole range of parameters before she/he is sure that that roast is the same as past roasts.
Conditions such as ambient temperature, room humidity, water content and temperature of the green beans, the chaff (the loose thin parchment surrounding and trapped in the central join the green beans) content, even gas pressures and the temperature of the roasting drum all play a vital part in achieving that elusive consistency.
The chemistry of coffee roasting is complex and still not completely understood. This is owing to the variety of beans, as well as to the complexity of the coffee essence which changes several times during different heat exchanges during the roast, which still defies chemists' best efforts to duplicate it in the laboratory.
The bean loses a good deal of its moisture, for instance, which means it weighs less after roasting. Therefore, if you start roasting at a certain weight you must control the flame and air blower accordingly during the roast as the bean weight drops.
The beans also lose some protein, about 10 to 15 percent of its caffeine, and traces of other chemicals. Sugars are burned or even caramelised which contributes colour and some body to the cup.
The diagram below shows an advanced roaster and the main heat and air control elements. Professional roasters can take several years of roasting expertise to master this machine.
This is very similar to the machine used at Coast Coffee.
Most roasting equipment uses a rotating drum above a heat source, usually a gas flame. The drum rotates, tumbling the beans to ensuring an even roast. The air temperature inside the drum is usually controlled at about 500 degrees F; the precise temperature depends on the intentions and philosophy of the operator.
Eventually, the deep "bound" moisture is forced out, expanding the bean and producing a snapping or crackling noise. Then, when the interior temperature of the bean reaches about 400 degrees F, the oil suddenly begins developing.
This process is called pyrolysis and the beans take on a darker colour. This is the moment of truth for the coffee roaster, because the pyrolysis must be stopped at precisely the right moment to obtain the flavour and roast desired. If the roaster misses this point that roast will be different to the next roast.
They are quickly dumped into a cooling tray where pyrolysis continues until the beans are quenched with either cold air or a light spray of cold water.
The chemical changes are still occurring during the cooling down period until room temperature is reached.
Typically, a roast will take from between 10 -
14 minutes, sometimes longer for a severely dark roast, but the first 7 -
9 minutes are the slower warming up process leaving the main exchange of events occurring between 9 and 14 minutes. Therefore a roaster has a window of a mere five minutes to make a wide range of decisions based a on a wide number of factors any of which will, if only slightly wrong, will affect the final roast and taste of the coffee.
Ever since the first bean was roasted hundreds of years ago this dynamic decision-making process has caused problems in creating a consistent roast.
The Automatic Profiling Roaster
For hundreds of years roasters have relied on their experience and mainly on eye, ear and nose to assimilate all the variables into a few minutes decision-making.
Until now...
Coast Coffee are delighted to announce that their latest computer controlled auto-profiler machine actually monitors all these variables using dynamic logic to adjust the roasting process according to any changes in the variables.
Essentially what this means is that there is now a system whereby each roast is monitored to precision to product a perfect roast each time, every time.
 We chose the Diedrich roasting Company, as according to most industry sources they make the '
best of the best'
. When coupled with a touch-screen controlled automatic computerised profiler we know we are able to produce a consistent coffee time after time.
Using a powerful CPU (computer processing unit) we are able to remove the need to think of a million and one different factors during the roasting process. But lets not remove the roaster'
s expertise altogether! There are still a wide range of variables that need to be considered prior and during roast which effect the outcome and continuous monitoring is still required.
Coast Coffee has invested heavily in this technology and is proud to associate this technology with the production of Bundaberg Blend coffee. Our roaster was awarded First Place for Best Product at the SCAA (Specialty Coffee Assoc. of America) Denver Conference and Exhibition 2003.
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