One of the most surprising things I have found is that there isn’t that much of an aroma”, said Steve Hampshire as he starts the process of roasting a brand new filter coffee.
One might expect the HQ of Roastology to be filled with the homely smell - but despite the bags of green beans sourced from estates in exotic spots across the world, the Tinsley base could be a warehouse for just about anything, aroma-wise.
Head of coffee Steve creates the company’s small batch roasts - which have just been taken on by Chatsworth Farm Shop.
“I think the Sheffield coffee scene has really been boosted by independent cafes - there are a lot more places to get a good coffee now”, said Steve, who took courses in roasting coffee.
“The taste of a coffee is so subjective. One thing I have got to be careful of as a roaster is that I might go down a road which I think is really exciting - but for other people it might not be.
“There are about 300 taste profiles that you can get out of wine - but there’s 1,000 you can get out of coffee.”
One way Roastology coffees are tested by a team is an unusual practice called cupping - more of which later. But what makes a good, or a bad coffee, when taste is such an individual concept?
“You are trying to detect positive or negative flavours”, said Steve, aged 33.
“Positive flavours are citrus, red berries, nuts and caramel - but negative might be baked or sour. There’s a massive difference between a citrus or a sour flavour.”
To start Steve starts to heat the ceramic plates inside the Diedrich IR-12 roaster - a gleaming machine capable of temperatures up to 500 °F, although the exact temperatures are kept under wraps. It operates using three types of heat to create the chemical reactions that form flavour.
Once at optimum temperature, five kilos of arabica Colombian beans - which look much like wizened lentils - are poured into the drum. A computer shows how the temperature then plummets, before beginning to rise again. It’s a long way from how coffee was first roasted in metal pans in the 15th century.
Steve, of Greenhill, added: “You could roast coffee on a baking tray at home if you wanted to. It is cooking - in effect. The way we do it gives a more even roast. At this point we are drying out the beans, which have 11.7 per cent of moisture in them. The bean will start changing colour as it caramelizes.”
Sure enough, the small sample of visible beans adapt to yellow, smelling like burned hay, then to cinnamon, with burnt popcorn, before starting to actually pop inside the drum in what roasters call ‘first crack’.
It means they have taken on as much heat as they can, and shortly after they are released to cool over four minutes - with the whole process taking only 15. We taste the cooled beans to judge if they have been roasted enough.
They are packed away to de-gas, which is when final flavours and smells emerge.
Cupping involves roasts Steve made earlier - where beans are grinded, left to brew in hot water until they form a crust, before we use a spoon to break the seal, inhale deeply and then almost slurp the coffee quickly in, to cover the whole mouth and tongue with liquid.
“When we do this for about 20 minutes we will be in silence, tasting as much as we can”, said Steve.
“I can’t speak for the whole of Sheffield so it is really important for us to examine what is good, what is bad, will this make a good morning coffee? There is a massive thought process.”
* The Telegraph has limited samples of the Columbian roast, already ground, for readers. Email email@example.com.