The Flavour Journey Part 3: Coffee Roasting

Welcome back to The Flavour Journey. This is part three of a series of articles which follow your favourite drink from Crop to Cup, the previous articles can be found {here} and {here} and I recommend you give them a read before this one. This time we are taking a look at the modern day alchemical art that is roasting coffee beans.

When you first start to taste coffee it can be an eye opening experience. It’s amazing that a single drink can have such varied and complex flavour, but it really does.

Readying for Consumption

Once coffee has been harvested, processed and made its way to its new destination, we dive into a whole new world of flavour factors, roasting the beans. Roasting coffee may sound like a fairly simple concept, but once again there is a lot more to it than just adding heat to your beans.

When we roast coffee beans the enzymes and makeup of the bean change and it breaks down in various ways, each of these factors in turn altering the flavour. In it’s short form, if such a thing exists, roasting is all about timing and temperature. The longer a bean is roasted, the darker and more bitter it becomes, while a lighter roast will emphasise the fruity and natural flavours of the bean. This rule of thumb can suffice when first explaining roasting.

However if we dig a little deeper we can start to see how and why the flavours develop as they do, and gain some understanding of how an artisan roaster judges and develops coffee. The green coffee bean passes through a number of distinct stages as it is exposed to regulated heat, once more I will digress into a little technical detail, if you will come along for the ride.

Coffee and Heat: A Match Made in Heaven

Coffee legend would have it that when the goatherd Kaldi brought the strange beans which had made both his goats and he “dance” upon eating them, to his local wise man, that the wise man declared them to be a terrible danger and threw them into the campfire. But as the beans met the flames a wonderful smell arose and the two men quickly grabbed them from the fire and tried them, and so coffee roasting was born…

This is most likely of course to be allegory and myth, but as is so often the case it contains a grain or two of truth. Coffee and flame really can produce magic, or perhaps more accurately a form of alchemy.

Starting to Roast

When first exposed to heat coffee beans will begin to pale, as the outermost enzymes burn away and they dry out with moisture loss. This change in shade will continue as the beans roast, and in some cases even leaves a bean that borders on white in appearance. As this happens the beans will naturally give off an earthy grasslike aroma.

As the beans roast further they will start to yellow, the pale colour changing as the temperature of the bean increases. Food lovers, scientists and the like may well recognise this as a visible sign of the Maillard Effect, the reducing sugars of the beans are reacting with their natural amino acids and developing more and more natural changes in flavour (this effect is seen in foods as they caramelise and is a fundamental part of the art of cooking). The smell of the beans becomes more like that of dried grass or hay during this period of roasting.

The Maillard effect continues as the temperature rises and the beans will continue to change in colour, becoming orange or tan as the sugars reduce further. This darkening comes with a change in aroma, more sweetness can be detected at this stage. Some have compared the smell at this stage in roasting to that of baking bread, not a bad analogy really. This is probably the first point in roasting where the beans start to smell more “coffee-like” with the aromas balancing out as the beans intensify.

The First Crack

As the beans approach 165 C we can observe a piece of coffee magic. At around this temperature the beans will make a popping sound, their exterior is breaking under the pressure of expansion caused by the heat, it’s somewhat akin to popcorn (indeed many home and small batch roasters have started their careers using modified popcorn machines as roasters).

This sound gives rise to a critical coffee term the “First Crack”. This stage is possibly the most vital one to recognise in roasting coffee, as it’s a natural sign that the beans are roasted to a level that makes them viable for grinding and brewing. Try brewing the beans any earlier than this and you will find the flavour deeply challenging and rather unpleasant, and that’s putting it mildly folks.

Ok so there we have it right? Coffee roast and ready to go? Well yes and then again no. As ever in the world of coffee it’s complicated and all about choices. While arrival at this stage could be considered an end in itself, really for the roaster it’s a gateway into a world of hard work and frankly for many coffee lovers, yours truly included, satisfying geekery.

The Alchemists Art

While we could just roast a bean to first crack and call it a done deal, it would be at the cost of so much of the coffee’s potential. The beans are still changing in flavour as we go and a lot can be gained and lost as they do, in fact roasters will often refer to everything that follows the first crack as “Development Stage Roasting”.

This is where we enter the heart of the roaster’s skill set, a complex, nigh-alchemical, blend of science and artistry that will always command my fascination and respect. Past the first crack the flavours and aromas of the roasting beans will change, and change rapidly. In a matter of seconds a roast can go from ideal to sub-par, the required result lost as the chemical processes within the beans alter flavour profiles.

You will often hear the terms, light roast, dark roast or perhaps short and long roast, but what do they really mean? and why should they matter to you? Time to break it all down.

Development, Second Crack & Beyond

The longer you roast past first crack the more the beans will darken, as part of this process the more fruity and natural acidic flavours will leave the beans, the relevant chemicals cooking off. As the bean darkens so the flavour profile deepens, nutty and chocolate notes will show through and the sweetness of some varieties can take center stage.

Eventually the beans will reach “Second Crack” once more making a popping sound, albeit a more subtle one than at first crack, as the oils within the coffee break the surface of the bean, this will also produce a significant change in appearance. Here the bitter note of coffee is the star, its intensity finding purchase and often dominating the flavour profile. The further you go the more the coffees oils will make there way out of the beans, creating a dark sheen on the surface, these oily “dark roasts” were historically very popular in Europe (indeed the terms French or Italian roast are still in fairly common use, referring to two levels of rather dark roast). The flavour is deep and intense, often described as smokey or tobacco like, to some people it can even become harsh and bitter beyond their desire to drink. Keep going too much longer and you will end up with charcoal though, so caution is advised in dark roasting your coffee.

Think of it like an orchestral performance, I promise it’s not as pretentious as it sounds, but actually a very good analogy for roasting in my experience. Opening with a gentle sound and tempo it focuses on the string sections’ light and airy notes, as the piece continues the deep tonal instruments in the background rise in volume and the lighter strings fade away, the whole nature of the music changes, and of course so does the audience to which it appeals. This is precisely the way flavours behave in roasting, a roaster picks their stopping point in the process to emphasise what they consider to be the best aspects of that specific bean and to appeal to a particular coffee drinker.

All of this happens faster than you may expect, while there are so many schools and methods of roasting that I cannot justify any sweeping statements, I will say that roasting won’t take much beyond 15-20 minutes. In that time your humble roaster will be watching the colour of the beans, considering the aroma and listening to the sounds inside the roaster, yes really, trust me it’s fun to watch too.

All of this to ensure as best they can that the resulting coffee will match the profile of flavour they are aiming for. Oh yeah, and changes in atmosphere, temperature and weather all need to be considered before they can get started. Yet another moment to appreciate the dedication and talent of those who are part of your coffee’s journey from crop to cup.

Next time we will wind up the series by discussing the art of brewing your coffee…

About Bear Essentials Coffee

If you have enjoyed this or any of my writing please check out my Homepage to find out more about me and my work. Follow the blog and if you feel you can, drop a donation to support this project.

Thanks, – Bear

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