The roasting process
Coffee releases over 800 compounds during roasting – almost a third of them representing important aromatic notes. There are two important phases in the roasting process: the first crack and the second crack.
During the first phase, the coffee beans rapidly absorb heat and water within the bean turns into steam. As the steam creates more and more pressure within the bean, you can hear audible ‘pops’ – this is known as the first crack.
During the second phase of the roasting process, the decomposition of sugars, proteins and lipids takes place. The pressure driving the second crack is not caused by build-up of steam, but by the formation of gases like C0, C02 and N0x being driven out of the bean.
The freshly roasted coffee beans are then ground, soaked in hot water and left to stand while the flavours develop. Then Chris and a small group of experienced tasters note the particular smell and taste characteristics of the brew. This is make or break for a sample batch of beans. A thumbs up at this stage means that an order will go out for a bigger shipment of the same green beans, from the same farm. When the shipment arrives, the original roasting profile is fine-tuned so it can be transferred to the large roaster.
According to Chris there are no rights or wrongs when it comes to how you like your coffee. But there is definitely an art to coffee roasting — that’s something best left to the experts.
The art of coffee roasting
Coffee roasting and making fine wine have a lot in common. Anyone can do it badly but very few people have the experience, skill and that little touch of magic to turn green coffee beans into the perfect, evenly-roasted starting point for a fantastic cup of coffee.
From green beans to the perfect roast
Sourcing the best green beans grown in high altitude regions of the world’s coffee belt is a skill in itself. Here’s the story of how Altura sources green beans directly from coffee growers. Once a sample of green beans make it to New Zealand, they still have a long way to go before they are selected to be turned into freshly roasted Altura coffee.
Every sample of green beans is hand roasted in small sample roaster by Chris White. The moisture content in each batch varies depending on the climate of the country of origin and the specific growing conditions of the season, so Chris builds a unique roasting profile to bring out the best in the beans.