Coffee Roaster and Coffee Equipment Supplier
Qualitasse was founded in 1982 where it started out as one man, Brian Layton, selling filter coffee machines and coffee from the boot of his car. Fast forward and the business soon had premises (circa 1985), then larger premises (circa 1992), then a water cooler business was established (maybe 1998?) and at the same time espresso machines where being supplied and maintained alongside bean-to-cup machines, then the first coffee roaster was installed (probably around 2005), then a takeaway cup making machine started producing compostable takeaway cups (definitely 2022) ! Below we give an in-depth profile of one of our main specialities – coffee roasting – for which we are multiple award winners!
Coffee beans are the seeds of the cherries of the coffee tree, each cherry typically contains two beans whose flat sides face each other.
When steeped in hot water, raw or “green” coffee beans offer little in the way of what one might relate to as coffee taste and aroma.
Roasting green coffee creates a chemical change; the production and breakdown of many compounds and obviously the roaster helps. This in turn creates development of beautiful flavours when the beans are ground and steeped in hot water.
Some of the many effects roasting has include;
Change in colour from green to yellow to tan to brown to black (a step too far!)
Nearly double in size
Become half as dense
Gain and then loose sweetness
Become more acidic
Develop hundreds of aroma compounds
Pop loudly as they release pressurised gases and water vapour
The main goal of roasting is to optimise the flavours of coffees soluble profile as dissolved solids make up the brewed coffee taste.
Wet / Washed
This process pulps the cherry to remove the outer skin removing the sticky layer by fermentation. The bean are then washed to remove the loosened sticky layer and they are dryed in parchment either mechanically for 1-2 days or on the sun for 3-16 days.
Dry / Natural
This process consists of partially or completely drying the coffee cherries on the tree then husking the cherries to remove the skins.
Alternatively the cherries are picked when ripe and them dried before husking.
Pulped / Natural
With this process the coffee cherries are pulped to remove their skins and set to dry with their mucilage layer intact.
This method delivers a sweeter cleaner cup than the traditional natural process.
Jute bags are the most common and economical option for packing and transporting coffee and with this renewable resource the bags are also cost effective. They also add additional protection from moisture and odours and are a cheaper alternative to vacuum packing.
We often have many jute bags in various designs from around the world, available to buy. Please ask for details.
During roasting, coffee beans change from green to yellow to tan to brown and if roasted very dark then black (not ours though !).
There is no universal system for naming different stages of roasting as what one roaster calls a light roast another may call full roast.
Generally they are called the following;
Cinnamon
These beans are normally dropped from the roaster very early in first crack and the taste profile would be green grassy, often pea nutty very and very light bodied
City roast
Normally dropped in the late stages of first crack and the taste profile would be light bodied with high acidity.
Full city
Normally dropped just before second crack, the appearance of surface oils are or should be visible. The flavour profile would be a well balanced with moderate acidity, mellow caramel and medium body
Viennese
Dropped in the early stages of the second crack, oils have just begun to migrate from the bean surface and the typical profile would be equivalent to a chain coffee shop type drink.
French
These are normally oily beans with a pungent bitter-sweet and carbonised flavour. Expect burnt bitter and smoky with small hints of caramel as a taste profile.
Italian style
Almost all Italian style roasts are rancid by the time they are consumed because of how the beans degrade during the extended roasting profile and the taste profile is burnt smoky rancid with medium body.
A classic drum roaster consists of a solid rotating cylindrical shell drum with an open flame below the drum. The flame heats both the drum and the air to be drawn through the drum and a fan draws hot gases from the burner chamber though the rotating beans and exhausts the smoke. Steam and various by-products of roasting exit through the flue pipe.
The drums rotation mixes the beans while they absorb heat by conduction from direct contact with the hot drum and convection from the air flowing through the drum.
When the roast is finished the roaster opens the door to the drum, dropping the beans into the cooling tray. This constantly turns and stirs the beans while a powerful fan draws room temperature air through the beans to rapidly cool them.
Roast profile curves generally follow an “S curve” in which bean temperature drops initially for 70-90 seconds, bottoms out then rapidly increases. In reality, bean temperature does not drop. The beans enter the roaster at room temperature and immediately get hotter. The initial temperature drop is in fact due to the air in the roaster influencing the bean probe.
Coffee loses 12-25% of its weight during roasting depending on initial moisture content but varies depending on the roasting profile. For example, dark roasts may have shrinkage of up to 22% or more, while light roasts might be 14-16%.
During the roasting process the beans start to emit a series of popping noises that begin quietly then accelerate reaching a crescendo and then taper off again. The beans are expanding and expelling chaff and the smoke development intensifies, first crack represents the sound of the water vapour and CO2 pressure being released from the bean core.
After first crack there is normally a quiet lull during which the CO2 pressure builds again in the core of the beans. This pressure is able to force oils to the beans surface and because of the first crack already having taken place the beans have weakened. Right around the time the first beads of oil appear on the beans the second crack begins, again releasing CO2 pressure and oils from the inner bean.
Roasting in to second crack destroys much of the unique character of the coffee and if taken too much further than early second crack then burnt carbonised flavours will appear.
Many rosters refer to the time between first and second crack as development time and most good roasters attempt to improve development especially in roasts for espresso by lengthening the roast time after first crack which will usually increase development of the bean. Extending too long at the last few minutes of a roast will normally leave baked flavour and should be avoided.
Freshly roasted coffee contains approx 2% carbon dioxide and the pressure within the beans causes the gases to be released slowly. During the first 12 hours or so after roasting the internal bean pressure is high enough to prevent oxygen from entering the bean but after this oxidation causes the beans to get stale and the flavour to degrade. This is why once the coffee is cooled it is packed in to bags with a one way valve (these are standard in the speciality coffee industry) which allows gas to escape but generally prevents new air from entering. Freshly roasted coffee in this type of bag will stay fresh for several weeks.