Like most subjective aspects of coffee, strength is subjective. It’s even hard to define. Evidently, everyone wants, like in love, something different in their relationship with coffee whether it can be in mouthfeel, viscosity or flavour.
The Strong Espresso Collection offers a range of dark roast profiles and blends that are progressively roasted darker. Each blend takes a particular green bean origin and processing method to create a key attribute of the blend. Then further body and flavour complexity is derived by blending an additional componentry of beans in density, size and origin.
The Table below is a guide to each of the blend attributes and mirrors the targets of the roaster, Joe, to measure the outcomes of the particular roast profile.
With the flavour of dark notes, their intensity increases as greater heat and advancing time increasingly influences the roast outcome. The Strength figure reflects this progr
essive change in cup profile.
There is also an inevitable change in the mouthfeel of the blend as it advances along the roast profile timeline, this is in the form of a naturally declining acidity in the cup as the related compounds, principally mild quinnic, malic and acetic acids are destroyed by the advancing heat and time.
We simply express a starting point for Acidity measurement as an indicative % and this reduces to effectively zilch and a very smooth and flat cup profile is produced.
Development Time Ratio [DTR %]
Progressive time in the roaster is measured from first crack by the roaster and is calculated as time from First Crack to the end of the roast, as a percentage of total roast time. Roasters enjoy nothing more than discussing DTR%, so we included it here for you to be part of the conversation.
First Crack and Second Crack
In the roasting process the coffee beans has two stages when they make a distinctive cracking sound. At first crack the last of the water vapour in the bean is driven out through the porous ends of the beans and they are cinnamon in colour. It is only at this point that you can make anything in the name of coffee.
Around an equal amount of time that the beans took to get to first crack there is a second crack sound in the roast caused by the release of carbon dioxide through the beans. At this stage the beans are going to be notably darker in colour. You can roast through and after second crack but it will not be far thereafter that the beans will simply combust and glow like burning embers.
There is no definite rule as to determine the starting point of a dark roast in description of colour or otherwise. A roaster would certainly say that a starting point for general discussion about this starting point might be “Towards second crack.”
A definition of a coffee snob might be a person who refuses to drink a dark roast on the premise of lack of complexity in the cup. The argument is that a dark roast destroys the inherent flavour complexity of a bean, as flavour are burnt up and out of the chimney to the delight of passersby’s and replaced with a singular smooth cup.
A beans density has a lot to do with the outcome of any dark roast. A seed that is denser in its organic structure then another, for example an almond nut is denser than a cashew nut. Therefore it will take a lot more heat than the cashew before incinerating. That is, its centre will still taste nutty when the cashew nut is charring at centre. A denser or harder green coffee bean carries more flavour because it has taken a longer time to mature, it is slower growing and has gained a more fibrous structure. It will also take the heat. A darker roast requires a blend of differing density beans in order that there is a range of dark roast flavours. We tend towards a particular bean density and origin in any blend.
A strong coffee might be simply described as a coffee blend containing 100% Robusta beans as in instant coffee. This bean varietal is say half the price of arabica beans and it can have a very rough and ready taste reminiscent of motor oil and burnt rubber. It generates more coffee oils, and has double the caffeine.
There are an increasing amount of specialty robusta beans coming to market, Estate Robustas, sun dried and wet processed and we use this new sourcing within the blends.