Roasting Gourmet Coffee

Science and Art

Magic beans

They come to us green, hard, tasteless. They are shipped from countries like Ethiopia, Guatemala, Peru, Mexico, and East Timor. Shipped in 132 pound sacks. The green beans smell like grass, hay, or the earth. Like Jack’s famous beanstalk bean, they are unassuming, dense, even boring.

But then, if you add fire …

Alchemy can be described as being part science, part art, part magic. Roasting certainly shares these characteristics. Our Probat uses the same basic design that has been used for centuries of coffee roasting. The roaster is essentially a horizontal drum with an axel through the centre. Fire breathing jets heat the sides of the drum as it rotates. The coffee enters the drum through a hopper at the top, does several thousand heated laps inside, and exits through a large door at the front. It falls onto a spinning tray with thousands of little holes. Air is sucked around the beans through the holes to enable rapid cooling of the beans – otherwise they will keep on roasting themselves.

A big part of the science of roasting involves temperature and time. The drum needs to be hot when the beans are dumped in. They quickly absorb that heat and as a result the drum temperature decreases. The job of the Roaster is to keep the temperature at the appropriate levels throughout the roast. Temperature probes penetrate different spots in the roaster, the data flow is monitored and the machine is adjusted as needed. The timing of the temperature changes is key as is the duration of the roast. The longer the roast, the darker the coffee. As the coffee is roasted, moisture in the beans becomes steam, the starches become sugars, the sugars caramelize. The oils in the beans move towards the surface. This oil, caffeol, represents a small component of the bean, but is the source of most of coffee’s flavour and aroma. At the end of all this the beans will lose up to 25% of their weight but will also nearly double in size.

The way a roast is replicated is through a recipe called a Roast Profile. Whenever a new bean origin arrives at Planet Bean, a new Roast Profile must be created. An origin relates to the specific and singular characteristics of a bean. It includes the country of origin, the area it is grown in, the altitude of the coffee bushes and the coffee’s family history. Single origin coffees are unique. This uniqueness can even vary in the beans from same bush from harvest to harvest. Our alchemists find the point in the roast at which each single origin is at its peak flavour. We also create blended coffees by putting various amounts of complimentary single origins together. We like to say it is like the difference between a brilliant musical solo, or a rousing ensemble, both equally enjoyable.

The art of roasting revolves primarily around the use of the senses. Our roasters spend a great deal of time revealing the flavourful truth of each coffee origin. If you visit our roastery at the Grange Plaza location, you can watch the roasting process through a window. You will see Dave or Harley pulling small samples from the roaster with the “tryer” as the beans cook.

They observe the changing colour of the beans, smell them, and listen as they make different “popping” or “cracking” noises at different stages in the roast.

“The first crack signifies the release of pressure that has built up inside the bean, and the only way for the pressure to be released is for the beans to physically split open” explains Dave. “The first crack is rather loud, and sounds like corn popping in a popper. The second crack begins when the heat applied to the beans begins to force the caramelized sugars to the surface through the pores of the beans. Of course, there is also the dreaded third crack … something that no roaster wants to hear.”

“Throughout the roasting process, the beans go through massive aroma changes,” says Dave. “At the start of the roast, moisture is being driven from the beans which results in a grassy/grainey like fragarance. When the beans enter the first crack stage, the aroma changes to something more like bread or even a toasty aroma. As second crack draws near, sugars are caramelizing in a rapid fashion, and the aromas change very quickly. Dark chocolate, caramel and also some very fruity aromas begin to materialize, especially in our sundried coffees.”

As for the magic of coffee roasting, come in to Planet Bean and you can taste it.

At Planet Bean we are proud to be Guelph’s coffee company, bringing back the tradition of local coffee roasting to our City. As Michaele Weissman writes in God in A Cup, “Throughout the nineteenth century, most American homemakers purchased freshly roasted coffee. Grocers often roasted their own, and most towns and cities of any size were home to one or more coffee roasteries. In the first half of the twentieth century, however, coffee, like other foodstuffs, fell victim to the industrialization of the food supply. Consolidation. Technological innovations. Standardization. They all led to one outcome: heavily advertised national brands of coffee sold in supermarkets in vacuum-sealed cans.” We would like to add that these stale mass produced coffees brought flavour standards to an all time low.

The key for flavourful coffee is to make your brew with beans that are freshly roasted. Planet Bean provides you with the best tasting coffee possible, grown without chemicals and paid for in a way that is fair to farmers.