The Top Eight Influences on Coffee Flavour
December 11, 2017

The Top Eight Influences on Coffee Flavour

We recently conducted a survey with some of our regular customers to find out why they keep returning to our coffee.  The message back was loud and clear - the primary reason is flavour!   There were other reasons including: value for money; coffee freshness; good customer service and reliability.  But, by far the top reason was “consistently great flavour”.  And we were delighted to hear this, because, when we set-up Spiller & Tait, we wanted to focus on offering a small range of great tasting coffees which all offer a consistent flavour experience.  That is, coffees which are smooth and rich in flavour, but lacking in bitterness.  The specific flavours of each of our coffees vary significantly, but they all share these general traits, because we know from experience that it’s what most UK consumers are looking for in their fresh coffee.

This feedback caused us to reflect on all the things we consider when composing a blend of coffee, or choosing single origin beans.  So, we thought we would share our insights on the broad range of factors that influence the characteristics of flavour in your coffee.  From earthy tones to sweet fruit flavours, to floral and tea-like aromatics, there's an incredible spectrum of taste experiences to be had through coffee and that’s before you add stuff to it!  But, what is it that determines which of these characteristics will be found in your coffee?  Unfortunately, there isn't a simple answer to that question.

The science behind coffee flavour is still in the early stages and we're only just starting to understand what is happening at the chemical level. There are probably influences we are not aware of yet, and nobody is certain how much each step in the coffee supply chain influences the final product.  However, we are clear about the most important influences.  Many of you can probably identify several flavour-influencers as well.  Most know that the roast level of the beans matters, and many of our customers also tend to think about origin as well.  But we would like to go back to the start of the coffee production process and highlight some of the important steps along the way that determine what you'll taste in your carefully brewed cup of coffee.


1) Variety 

Even before the plant that bears the coffee fruit has begun to grow, there's a very important factor that will influence the crop - the variety. It's not as simple as Arabica vs. Robusta varieties.  Within each of these species, there are dozens of known varieties, and more being discovered and created with time.  Wine lovers say that grape variety is a huge impact on the flavour of what's in the glass.  A Merlot has very different characteristics from a Pinot Noir, or a Malbec.  Similarly in coffee, which variety (or combination thereof) is in your coffee will have a big influence on the flavour you experience.

Most coffee lovers don't talk much about this important factor quite enough.  If you want to learn a little more about variety and its impact on flavour, read more on our website here.


2) Terroir (pronounced “terwar”)

Whether you're talking about wine or coffee, terroir is one of those lofty French terms that can alienate some people, but really, terroir is just the influence of where the coffee is grown. We all know that coffees from Kenya generally taste pretty different to coffees from Brazil. We also know that coffees from nearby areas can have similarities. These are the results of the influences of terroir.

Of course the specific elements of a terroir that are responsible for the impact on coffee flavour are numerous and complex, but here are some of the important ones: altitude, climate, soil type, topography.

We're certainly not suggesting that you need to understand every element of the terroir of every coffee you drink, but paying attention to where your coffee comes from, and what some of the defining characteristics of that terroir are, is helpful if you want to understand your coffee better.

For more insight into the impact on flavour of terroir in some of the main coffee growing regions, read more on our website here.


3) Farming Practices 

Perhaps one of the most important and least understood influences, the practices of the farm where the coffee is grown has a huge impact on the taste of the coffee you drink. Everything from the use of chemicals to planting patterns & pruning regimen are ultimately going to affect the nature of the crop.

One particularly important farming practice is picking.  Much as with other agricultural crops, coffee is best when it is picked at optimal ripeness.  But of course, coffee cherries don't ripen at a uniform rate. This means that for the best results, cherries must be picked by hand, by pickers who are trained and incentivised to pay attention to the ripeness of the fruit they are harvesting.

Commercial-grade coffee is often strip-picked (i.e. whole clusters of fruit are picked at once) or machine-picked, which means that the final product is a combination of ripe and unripe fruit. While this is less expensive, it does not yield top quality coffee!  All Spiller & Tait coffee falls under the category of Speciality, or top quality, and almost all of our beans come from fruit which has been hand-picked.  

In the case of our Classic Italian Blend, we do use a commercially grown Robusta bean which has been strip-picked.  The immaturity of some of these beans adds a harshness of flavour which provides balance and depth of flavour to that particular blend, which we feel works very well.  These beans also add the caffeine strength many of our customers are seeking in that blend.


4) Processing

Once a coffee cherry is picked, the coffee seed has to be dried before being transported for roasting.  The ways this is done can vary widely and can have a large influence on what the coffee finally tastes like.  While this is a complicated topic in and of itself, here are a few categories to look out for:

Natural or dry  this is the traditional African method of processing coffees. In this method, the coffee is actually dried while still in its fruit. This has the benefit of not requiring large amounts of running water and also allows more of the natural sugars of the coffee cherry to wind up in the bean that gets roasted.  Natural processed coffees tend to have fruity flavours, and low acidity, although sometimes they're also found to have lower clarity.  While this method of processing can be more economical in its execution, it runs a higher risk of crop spoilage and the cherries must be manually turned frequently to minimise this risk.

Washed or wet-processed coffees – this more modern style of processing involves briefly fermenting the coffee cherries and then removing the seeds from the fruit or pulp - 'washing'. This method has an advantage in that with the outer, fruity layer, some of the risk of spoilage is removed.  Washed coffees tend to have higher acidity and more clarity, characteristics that have made them very popular in the industry’s “third wave” of single origin coffee.  To learn more about single origin coffees verses blends, click here.

Honey-processed – while wet & dry processing have their benefits, a third way of processing coffee has emerged that is meant to balance the benefits of both methods.  In very simple terms, honey-processed coffees are dried with some but not all of the outer layer of the coffee cherry removed.

There are many more different styles of coffee processing, often referred to by the colour of the final dried crop (yellow, red, black) and, for the most part, they just entail removal of different amounts of the outer mucilage.  Spiller & Tait beans tend to be washed, and this method helps to create a consistent and reliable flavour.  But we also use dry and honey processed beans when they offer the flavour characteristics we are looking for in a blend.


5) Roast Profile

This is more familiar territory for most coffee drinkers, but that doesn't mean that we shouldn't reflect carefully on the impact of roast profile on flavour.  Not even the most talented roaster can take poor quality green beans and make it taste delicious, but an un-skilled roaster can certainly ruin a great batch.

After sourcing and selection, the roaster helps to realise the full potential of the coffee by carefully crafting a roast profile that will suit that set of beans. This isn't as simple as light or dark.  Indeed, roast colour can be pretty misleading. The roaster has to fine tune variables like roast time, charge temperature, rate of rise, drum speed, air flow & cooling speed, while responding to data like temperature logs, first and second crack timing, and most importantly sensory experience.

This process of calibrating the roast for the desired flavour takes time and is costly, particularly since several batches have to be roasted before the coffee can be sold. But, once this process has been completed, a well roasted coffee isn't just pleasant to drink, it's also distinctive.  It helps us to experience the influences of all the steps that came before that roast.


6) Blending

Most of the coffee sold a few decades ago was blended. While that's still probably true across the coffee industry as a whole, in the Speciality Coffee segment in which Spiller & Tait operates, single origins are becoming increasingly popular. That is probably because they enable the drinker to experience the fruits of the coffee farmer's labour.

Nevertheless, blending can be a masterful craft in its own right. In its basic forms, it can ensure a more consistent flavour experience throughout the year as the inputs to that blend change with the season. At its best, a blend can be a unique taste experience, whose flavour is more than just a sum of its component parts.  It's worth acknowledging that one of the primary reasons that some roasters blend is not necessarily to create a better flavour experience but to create a decent one at a lower cost.  By combining high quality and lower quality components, you can produce something very drinkable at a much lower cost per kg.

Most of Spiller & Tait coffees are blends, and this is primarily because blending enables us to create the general flavour characteristics with which we want to be associated.  That is, coffees which are consistently smooth, balanced, rich in flavour, but lacking in bitterness.  We also have two blends which include some slightly lower quality beans, in order that they can be offered at a more affordable price.  We believe our Barista Blend and Super Crema Blend stack up against all our other coffees for flavour, even though they have a minor quantity of lower quality beans.

Learn more about our Spiller & Tait blends here.


7) Freshness

Prevailing wisdom in the coffee industry is that all coffee starts to become stale and lose flavour after a few days after roasting.  The mantra is very much that fresh is best.  However, in our experience, there is a slight caveat to that phrase.  Like meat, we believe coffee needs to rest after it has been exposed to high heat. The aromatic compounds, the main source of flavour in coffee, often take time to develop after roasting.  So, we believe that fresh and rested is best.  But how long should a coffee rest? 

Our experience with our own freshly roasted coffee suggests roasted beans can reach a delicious taste profile within minutes, but this is rare.  Many reach an optimal taste within hours, but most coffees are best if left at least 1 day, and many are best left up to 7 days. This depends largely upon the variety of the bean and the degree of roast. Some varieties, notably our espresso blends, are at their best 5 to 6 days after roasting.

How the coffee is stored while resting is also important.  Roasted beans give off a considerable quantity of carbon dioxide (CO2) while resting; this emission continues at a reduced level over a couple of weeks, and, if the beans remain in contact with the CO2, this can cause the aromatic oils to degrade.  

At Spiller & Tait, all of our coffees are packed within minutes of roasting into mylar plastic bags, which have a foil lining and a one-way valve.  These bags are ideal short term storage for freshly roasted coffee.  They protect the coffee during the resting period by releasing CO2 through the valve while preventing contact with Oxygen in the air, which also causes aromatic compounds to dissipate quickly and reduce flavour.


8) Brewing

Last but certainly not least, brewing is the final stage in the process before drinking, which can also have an important influence on coffee flavour. One mistake that new coffee lovers make is assuming that the exact same brewing parameters will bring out the best in every coffee. "What's your Aeropress recipe?" is certainly a common question among new aficionados.

Any barista will tell you that your brewing variables need to match the coffee you’re brewing, as well as the brew method. In the case of espresso, they may even need to be tweaked to respond to ambient conditions like heat, humidity and altitude. Even in a simple manual brew method, changes in brewing variables can be the difference between a decent and a delicious cup.  For more information on the brewing methods which suit each of our coffees, follow this link for a guide through our different blends.


Other important variables in brewing are:

+ Brew ratio (water to coffee)

+ Grind size (and uniformity)

+ Extraction time

+ Water temperature


This is where you have the most influence over your coffee’s flavour.  So, when brewing for yourself, we encourage you to challenge yourself to bring the best out of every bag of beans you buy. If you're not experimenting and tweaking, you may be missing out on the best your coffee can be.  The various Brewing Guides on our website are a great place to start to get the best from your chosen coffee-making device, view our coffee brewing guides here.

Other Flavour Influences

Sorry, we said there were only Eight!  Although we think these 8 are the most influential, they are not the only ones.  In truth, we probably don't even know them all.  Here are a few others that at least deserve a mention:

+ Age of harvest (crop freshness)

+ Packaging (how the green beans get from origin to roaster)

+ Age of roast (roasted bean freshness)

+ Packaging again (but this time of the roasted beans, and allowing the CO2 to be released)

+ Storage (both pre- and post-roasting)

In conclusion

Hopefully you can appreciate why we are so pleased to receive awards and glowing customer feedback on the great flavour of our coffee.  It takes a lot of knowledge and work to get the desired flavour and to delivery that consistently. 

Much of the content of this blog therefore involves drastic simplification. The reality is, you could devote a significant chunk of a lifetime to understanding any one of the eight factors mentioned above.  Nevertheless, pursuing some understanding of each of these variables is an important part of the appreciation of coffee.


It's also worth noting that while each of the steps we've covered will have a significant impact on the flavour of the coffee you buy, the pre-roasting variables (1 – 4) are the most significant influence on what you pay, since these impact the price that the coffee roaster pays for the green beans.  So, when you wonder why one coffee may cost much more than another, you probably need to look to these pre-roasting steps in the process.