The Coffee Roasting Process

Green Been Processes We Use

Although what follows below is a general description of the coffee roasting process, we believe it important that we note the roasting process we follow is part of our uniqueness.

All fine food and drink are affected by how they are prepared, that is why we ensure that we have selected only the finest roaster. All our beans are slow roasted in clear hot air. The roaster uses a ceramic plate that is heated in a contained system, so that only clean air is radiated into the roasting barrel. The beans spend over half the time in the roasted being slowly heated up, so that all flavour and aroma is retained. The roast progresses at s controlled pace ensuring that the roast level we believe have identified as the most scrumptious is reached. Then the beans are emptied into an air cooling bin, and the roast is arrested. We allow the beans to cool naturally.

What makes our process different is that at no point are the beans exposed to harmful exhaust gas or water, the beans are roasted in a controlled manner, and no water is used during the cooling stage. Each gram of coffee we pack is coffee, no extra water.

Our roast times change depending on the climate and green bean used. None of our roasts take less than 10 minutes and most go no longer than 17 minutes, typically our roasts take about 12 minutes. Each roast is individually monitored to ensure the desired look; feel and aroma characteristics are achieved, and for us most importantly the oils must still be retained by the bean, so they can be enjoyed when the bean is ground.

Bean Used

The lower the quality of a coffee bean the darker the roast has to be to extract any flavour out of the bean. One of the reasons for this is that the coffee taste comes mainly from the oils in the bean, and as you roast the bean darker more of the oil comes to the surface (it is actually pushed out almost). The better beans can be full of flavour at very light roasts.

At Quaffee we ensure that our beans are roasted to a level where we have found them most tasty. This normally means past the first pop (about an 8 on the picture) and no further than second pop starting (about 12 on the picture). It is worth noting that the darker the roast the fresher the roasted bean has to be to fully enjoy it, since the closer the oils are to the surface the less they are protected from exposure and it is commonly known that oil exposed to light goes off quicker.

Culture

Culture plays an important part in the expectation of taste. Most cultures prefer a particular taste because it has become a tradition. The French dark roast their beans (about a 15), the Italians not as dark (about a 14). This is mainly because there is a belief that darker roasts decrease acidity. It does but it also decreases flavour, replacing delicate coffee flavours with an almost burnt toast taste. Most of Europe chooses the darker 13+ roasts. This may be related to the fact that although Europeans initially started drinking their coffees from the true source namely Africa, once the modified beans made it to Brazil, and the Robusta's were introduced in the 30's the only way flavour could be reached was to dark roast. We at Quaffee believe that these roasts are not desirable, and none of our roasts will ever go past 12, otherwise it is disposed of.

The art of coffee roasting has made dramatic improvements in recent years. Roasting coffee changes the chemistry and physical characteristics of the green coffee bean. The beans shrink in weight depending on the roast profile. Typically a lighter roast is about 15% and a darker roast about 20% by weight. During the roasting the beans acquire the hue and aroma of fresh roasted coffee.

Coffee roasting is a chemical process by which aromatics, acids, and other flavour components are either created, balanced, or altered in a way that should augment the flavour, acidity, aftertaste and body of the coffee as desired by the roaster.

The first stage of roasting is endothermic (beans absorb heat), where the green beans are slowly dried to become a yellow colour and the beans begin to smell like toast or popcorn.

The second step, often called the first crack, occurs at approximately 205°C in which the bean increases in size, becomes a light brown colour, and experiences a weight loss of approximately 5 %. The corresponding Agtron number for this colour is between 95-90 (Davids, Roasting, 68).

As already stated our beans are not roasted further than this step as we believe this is were the optimum flavour is achieved

HOWEVER for reference, in the next step the temperature rises from 205 °C to approximately 220 °C, the colour changes from light brown to medium brown (Agtron # 60-50), and a weight loss of approximately 13% occurs (Davids, Roasting, 68). The resulting chemical process is called pyrolysis and is characterized by a change in the chemical composition of the bean as well as a release of CO2. The second step is followed by a short endothermic period, which is followed by another exothermic (beans release heat) step called the second crack. This second pyrolysis occurs between 225-230°C, and the roast colour is defined as medium-dark brown (Agtron #50-45) (Davids, Roasting, 68). The second pop is much quicker sounding and the beans take on an oily sheen. Roasting well into the second pop or darker is not favourable since volatile aromatic compounds are stripped off and oils on the outside of the bean are more easily oxidized. Unfortunately there is a world wide trend, that has its base in the lower quality beans, to roast to a dark black, with a bright-shiny surface (this is actually oil), and a final temperature of 240°C. This type of roast is often preferred by some coffee-sellers since it masks poor blending, dirty machines, and stale coffee.

Every coffee will taste different at different roast degrees. A roast will bring out certain nuances that will lend themselves to amplification. Until there is a scientific way to predetermine proper roast degree it is necessary to experiment until you achieve the desired flavours.