Most people think a coffee roaster just heats any type of green coffee beans until they are brown - like cooking meat in an over, pan or BBQ, but there is a whole lot more science and skill involved.
When it comes to coffee, the world has many experts - from the local cafe barista, the internet forum blogger or the guy who tells all his friends he can only drink his own home roasted coffee beans because it's fresher and higher quality than anything else he can buy.
The reality is coffee is extremely complex. At each stage in the lifecycle from farmers tending to crops, processing the harvested cherries, transport and storage of green beans and then what the roaster does in his equipment and finally the distribution and extraction (brewing) of the finished product for consumption.
At each stage, there are considerable risks and issues associated with the handling of coffee that can result in a reduction of the end-cup quality. Generally speaking, the higher risks of poor cup are at the brewing and roasting stage.
Farming and Origin risks
Farmers are becoming more informed of improved practices that can yield them higher prices for better quality raw green coffee beans. The standard continues to rise with the growing markets size and demands for specialty coffee.
We continue to see the market for lower-grade coffees contracting (usually supplied to provders servicing the instant and supermarket grade coffees).
Harvesting and processing coffee cherries play an important part in determining bean quality. As with many agricultural products, coffee is subject to nature and all it's variances as the coffee trees bloom from flowering into cherries that ripen.
Coffee is grown at high altitudes and in many countries the majority of the cherries are harvested by hand which means there are risks of under-ripe, over-ripe, pest-ravaged and other less than ideal cherries from being collected by pickers to "fill the sack". Pickers traditionally get paid per sack, so the incentive in some areas for selecting high-quality cherries is less of a driver for quality than filling the sack.
Grading and Processing
The grading of the coffees at the Co-ops and processing stations is the next area where quality can be enhanced. Co-Ops and processing plants still practice the skill of blending - taking excellent coffees and mixing them with average in order to meet grade requirements. However, some farms are taking control of their processing by ensuring less blending and preserving the integrity of the harvested crop.
Processing is one area where the coffee quality can be either improved or destroyed. Unfortunately, processing techniques vary from region to region and the discipline and controls are better in some countries than others. For example - Costa Rican and some Central American farmers exercise absolute control over the processing methods - protecting the beans from the risk of adverse weather and avoiding ferment taints from poorly prepared coffees.
Sumatra is an origin that uses a unique process called wet-hulling. This process creates coffees of exceptional body and low acid, but run the risk of ferment taints such as mould developing that can destroy an otherwise fine coffee bean.
Processing methods such as unwashed, sundried, triple-picked can develop intensely sweet coffee beans. Ethiopia is famous for practicing some of the best unwashed, dry processed coffee beans.
Transport and Storage
Once the beans have been processed, the handling of the coffee needs to be carefully managed. Storage facilities at origin can be very basic and rudimentary - sometimes just a simple tin shed. Packing the beans into grainpro bags or vac-seal foil can be expensive at origin, but the benefits of having coffee beans that are stored in a package that reduces the impact of fumes and other toxins from being absorbed by the green beans leads to a higher quality bean. We purchase as many coffees as we can in grainpro bags. We would like to make it a universal policy of only purchasing grainpro bagged greens, but the reality today is that some origins and farms simply cannot provide this method. As at April 2012, approx. 35-40% of our coffees we purchase are shipped in grainpro and we see this ratio increasing as the demand forces the suppliers to provide this at origin.
Sometimes coffee is stuck in export sheds for months on end, awaiting buyers contracts, shipping vessels or port availability. As an example, some of our favourite coffee beans from PNG are from the Mount Hagan area. There is only 1 road from the highlands down to the distribution highway and this road gets washed out from heavy rains every year. Other countries like Uganda are land-locked, which means that need to have their coffee transported through another country in order to load onto a ship.
Containers get extremely hot and coffee sweats inside. This reduces the quality of the bean by the time it reaches the importer and roaster.
Green Bean selection and Roasting
Roasters select green beans based on a number of personal choices. Sometimes it is budget driven, trying to keep a blend within a certain price band so that other cost structures such as marketing, equipment and contract selling prices can be maintained.
Other times, it can be a desired taste, e.g. trying to compensate for a change in a new crop coffee that bring a blend back in line with a required specification.
Ultimately, roasters make these choices. At any time, there may be in excess of 200 different coffee beans available to Australian roasters from the major brokers.
Once a bean has been selected, whether it is roasted individually or mixed into a blend, the roaster needs to fully understand the capability of the bean. Some beans respond better at lighter roast levels, whilst other coffee beans will work better at darker levels. If a blend has many different beans, it is then important to ensure the selected bean works well with the others. Not all beans can be blended successfully together - there are acid, fruit, etc. considerations. I've blended beans in the past only to find out the hard way - they clash.
When it comes to roasting, every roaster thinks he is skilled and special. There is such a broad variation in the quality of roasting equipment to the extent that the Australian market has a lot of small roasting companies employing cheap roasting equipment that generate inconsistent results. It is a controversial statement to declare, but it's honest. I used to have a cheap Turkish roaster and whilst some of the batches it produced were great, there were many so-so and some that were downright horrendous.
Some Australian roasters using old or low-cost equipment also believe that by plugging in a cheap digital multimeter and logging the roast progress (monitor) on a laptop is called profiling. Nope, this is just watching and recording the action, it does nothing to compensate or target consistency. Profiling is controlling the heat (energy source), airflow and other parameters to ensure the required roast cycle follows a pre-defined path.
When sophisticated roasting equipment is used by skilled roasters with quality beans, the results are predictable and superb. We roast around 150+ batches a week and the deviation is less than a few seconds between each batch. So close is this tolerance it really comes down to ambient conditions. More importantly, we constantly cup the control samples - looking for defects or opportunities for improvements.
A common story we hear from customers calling our business is......"We used to buy brand X, but lately the coffee is not good and we just don't enjoy it". The answer to this situation is likely to be one of two possibilities - Brand X are buying green coffees that are inferior or the roaster (and blender) has not been able to create a roast profile or blend that develops the best from their beans.
Consistency is important in coffee. The largest variations we see in our coffees is in the Single Origins. As we are dealing with just 1 bean, it is subject to some minor deviations from bag to bag - particularly the dry-processed coffees such as Ethiopians that have that "wild" character.
Brewing and Extraction
It's been said many times before on the internet, but we have to say it again. All the work of the farmer, the processor, the transporter, the roaster, the distribution, etc. can all come undone if the coffee is not brewed or extracted correctly. Under and over-extraction are common issues affecting the flavor of coffee. Incorrect grind, dose and exposure to heat and pressure can cause taints.
Unfortunately, the consumer drinking the cup of coffee blames the coffee brand. Reality is that great beans, perfectly prepared will be destroyed in the hands of the unskilled barista.
Coffee flavor is an oil that required precise heat and pressure to extract. If these variables are not right for the particular brew method, then anything less than ideal is possible.