Carefully crafting the perfect cup of coffee
Discover the Rosso Coffee roasting process
By Robyn Welsh, Publishing Editor
Coffee aficionados gathered at Rosso Coffee Roasters in Ramsay on Thursday, Sept. 20 to learn about how coffee roasting turns pistachio-coloured beans into the commercialized brown coffee bean we all know. The event, Here’s to your Roast, was put on in collaboration with Beakerhead and sold out completely. Participants chose an hour-long tour time beginning at 6 p.m. and prepared for an evening caffeine buzz.
Guests were greeted by the overwhelming aroma of freshly roasted and brewed coffee. First, everyone gathered around the coffee roasting machine for a demonstration of the roasting process led by Paul Stephens, one of Rosso’s staff roasters. Stephens has been roasting coffee since 2001 and began working for Rosso two years ago.
The roasting process
Stephens demonstrated the roasting process while explaining it in detail. The roasting of the beans only takes about 10 minutes.
After pouring in the unroasted beans, the hopper temperature drops significantly and slowly begins to heat back up. The process begins silently. Tumbling beans can be seen through a tiny window into the machine. Slowly, the temperature begins to rise and is graphically tracked over time on a monitor. Air and gas adjustments are made throughout the process to control the temperature inside the hopper.
Things become more interesting around the seven minute mark when it sounds like tiny popcorn is being made. This is called first crack and coffee only becomes drinkable once it has been roasted past this point. Beans will look tan to light brown and increase in size at this point because a large amount of moisture has evaporated. Light roasts are cooled slightly after first crack and hold onto more acidity. Generally, the further the roasting process progresses, the less acidity in the coffee. Acidic levels in coffee beans translate to different flavour notes.
“There are natural acids present in the coffee, so say if you have lots of malic acid in the coffee, malic acid is the dominant acid in apples, so malic acid tastes like apples. So citric acid tastes like lemons,” says Stephens.
“I like to see how what we do in the roasting translates into how it tastes.”
– Paul Stephens
“So when you have more or less of those acids in the coffee, then you’ll get those kind of flavours.” Stephen says to determine the notes, “you try and eliminate the actual coffee taste itself and see what else is there besides the coffee.”
The acidic content of coffee is not only determined by the roasting process, but also the region the beans are grown, the type of beans and how they are processed post-harvest.
“Generally, the higher altitude a coffee is grown, the more acids will be produced in the fruit,” says Stephens.
All of Rosso’s coffee goes through a single cracking process. However, dark roasts will typically reach a second crack which releases the oils in the beans. This is why dark roast beans may look as though they have a coating of oil. In a lighter roast, the oil remains contained within the bean until ground and these oils are delivered to the cup in brewing methods that do not use a paper filter.
At the end of the roasting process, the beans are released into a cooling bin and spun for about six or seven minutes until cool.
After fully cooled, the beans can be ground. Before brewing any of the coffee, the grounds are put into a machine that looks like a microwave that gives off green light. This is called a Colour Track machine and a green laser is used to measure and assign a value to the darkness of the roast. This value is measured on a scale of one to 100. According to Stephens, on average Rosso produces coffee that is a 54 on this scale and is a light to medium roast.
Once their colour value is recorded, it is time for the coffee to be brewed and tasted. “I like to see how what we do in the roasting translates into how it tastes,” says Stephens. “I like roasting new coffees and seeing how they behave in the roaster.”
“All coffees will absorb heat in different ways and they roast at different speeds. They don’t all do the same things in the roaster at the same time,” says Stephens. “So it’s interesting getting a new coffee because you might have some idea of how it will behave because of where it’s grown and which country it’s from, but you never know fully how it’s going to do.”
Depending on the bean, when in the roaster, first crack will come at different times. According to Stephens, “Some will roast very quickly, some will be slower depending on their moisture level.”
After learning how the roasting process works, participants each filled a jar with freshly roasted beans to take home and headed to their brewing station of choice to learn more about variations in brewing methods.
The second half of the hour was a chance for guests to learn more about brewing processes. Three stations were set up: espresso, pour over and aeropress.
In all of their brewing methods, Rosso weighs out the coffee grounds to a specific weights. Espresso is weighed to 18 grams.
It does not matter what kind of beans are used to make espresso. Each roast affects the taste of the espresso and typically bags are labelled as espresso when the roaster thinks the notes lend well to espresso drinks. The acidity in some lighter roasts can be intense, but there tend to be more fruity notes. Darker roasts have more bitter and dark tones like chocolate.
Rosso worker Nelson Phu demonstrated the espresso brewing process. When brewing his drink, Phu and other baristas fill the handheld portafilter with grounds and tap it against the counter to equally distribute them. This helps ensure the flavour is extracted from the coffee throughout the basket equally, producing a more consistent espresso. The 18 grams of grounds Rosso puts into each shot brews 39 grams of espresso.
Phu directed participants to swirl the espresso to dissipate the light brown layer that forms on the top of espresso shots. This is carbon dioxide suspended in water and is called crema. Breaking this up will avoid an overly bitter taste from coming through. Once mixed in, crema gives the espresso a fuller flavour. This process also cools the espresso down a bit, improving the flavour profile of the coffee. Phu warned to never drink espresso too hot. Only after this did participants have a small sip of the espresso.
While steaming whole milk, Phu explained why milk and espresso are such an iconic pair. The foamed milk is a colloid and blocks certain flavour receptors on the tongue, making espresso more palatable for many consumers.
As the milk is being poured in, it is swirled together with the espresso to fully blend the crema. With the ideal ratio of espresso to milk in hand, participants were able to enjoy their cappuccinos and new coffee knowledge.
An evening caffeine-filled event like this was the perfect recipe for last-minute paper writing into the wee hours of the morning.