Spilling the beans: Coffee

Great Taste coordinators’ workshop 2025 with Marcello Geraci

Marcello Geraci has been specialising in coffee ever since he moved from Italy to the UK about 13 years ago.

The best place to start with reading or reviewing what was learnt in this workshop is with Marcello’s presentation, which can be downloaded via the button below. Below that you’ll find some useful notes and context gathered by the Guild of Fine Food team on the day.

By way of introduction, he talked our coordinators through his journey into coffee. He’s always been interested in food, sensory experience and all things from the “bella vita”, but actually didn’t get into coffee until he came to the UK.

He explained that the way we’ve experienced coffee has changed dramatically over the years. From Italian mocha pots and grandparents’ traditions, to a more scientific and schematic approach. That doesn’t mean everyone has to be a scientist when they get up in the morning, but it does mean that the coffee industry has become more technical, as has the consumer.

The growing, selecting, sourcing, roasting and grinding of coffee makes it a complex process that has many elements that affect the taste. For instance, at its most basic level, unripe coffee beans result in a sour coffee at the end of the process.

Like with other foods, for coffee, we’ll look at appearance, aroma, taste, and mouthfeel.

Aroma & taste: an activity to try at home

Aroma is made up of volatile compounds, the most complex elements. Actually what we perceive is about 80% of what we consider “taste”.

You can test this at home a packet of Skittles. Pick one, hold your taste and taste it. Keeping your nose closed, try and detect what flavour it is. Describe what you taste. Can you taste anything more than “sweet”? Didn’t think so! Now let go of your nose and you’ll find that the flavour (lemon, lime, blackcurrant, orange) becomes very pronounced. Proving the theory that aroma contributes to the vast majority of what we consider to be “taste”.

Taste is less complex than aroma. When thinking about taste, consider the “taste”, but also the aftertaste.

Bitter

Bitter and sour are sometimes difficult to distinguish. Bitter is historically our natural defence against poisonous plants: if it’s bitter, spit it out!

There are two different types of bitter in coffee:

Bitter can come from the roasting process and that means that more roast can give more caffeine, which can give the impression of more bitterness.

Burn is a slightly different bitterness, which comes from the carbon.

Think about it like the way acidity can from different sources such as citric (lemon), lactic (yoghurt) and acetic (vinegar).

Coffee plants

Marcello talked us through the key differences between the coffee plants (Arabica – Coffee arabica and Robusta – Coffee canephora). There is lots more information is in his presentation.

Caffeine is actually the defence of the coffee plant and it’s poisonous to bugs, and it’s bitter. Interestingly Robusta plants are more robust against bugs, due to the higher caffeine content.

We are losing Arabica due to climate change as it needs a cooler growing temperature. Some studies say that we will lose Arabica in the next ten years if things don’t start to change. Coffee plants are very sensitive to change and we’re in a period of extreme weather (both hot and cold), which is really affecting Arabica crops.

Robusta is very full-bodied and often not used on its own, but sometimes in a blend with Arabica. Arabica tends to be more likely to be used in speciality coffee.

Espresso – what should you expect?
Thick, creamy, emphasis on balanced sweetness and acidity. Bitterness can be present, but is general minimal and evened out by the sweetness and acidity.

Filter (pour over or drip) – what should you expect?
This won’t have the full body of espresso, instead it will be a more delicate, thinner texture, more like tea. This gives floral and fruit notes a chance to shine through. No oil as it’s been filtered out through the paper.

French press/cafetiere (Immersion) – what should you expect?
More mouthfeel, some fruitiness and there will be some oil due to the contact with the grounds. Metal filters pronounce acidity and oil.

The globalisation of coffee

It’s said that the discovery of coffee came because a goat herd saw his goats eating some berries from a bush and noticed that they seemed really energised after. The berries were picked and roasting and then brewed and tasted by humans to try and get the same effect. Where and when (and if!) this happened is up for debate, but what is for sure is that people the world over are involved in the coffee industry – from growers, to roasters, to consumers.

The ability to move plants, beans and other parts of agriculture around the world has confused some of the “traditional” outcomes from plants grown in certain areas. Now it’s harder to define coffee taste by region and plants can be transported around the world and the weather is changing too.

With all that in mind, Marcello recommends it’s actually better to consider the process that the coffee has gone through instead. (see “What is coffee processing? How they affect the flavours” page in the presentation for more information).

Tasting

We tried two coffees: a washed and natural processed and had to distinguish between them to guess which was which. (See slides for a guide on what to look for in each).

Ideally you should see the following on a packet of coffee:

• Process
• Elevation
• Origin
• Traceability

Marcello is personally against tasting notes, because all of our taste – and so what we consider to the different flavours in terms of words – are different. It’s a starting point, but ideally customers should try and learn what their preferences are in terms of process, origin and style, as well as which businesses they’d like to support in terms of who they feel is doing this well and treating their supply chain fairly.

We then tasted two more coffees: a blend (of washed & natural processed) and a dark roast (see slides for the differences).

Nothing is better or worse, but it gave a clear understanding of what we might individually prefer. Of course, as Great Taste judges, we need to see the merits of each process and what might make a good example of a coffee produced through each process.

Questions asked by our coordinators:

Is there price difference between washed & natural process coffee?
Washed takes more energy, equipment and also most washed coffee is grown in high elevation. It’s more manual, the labour is harder – remember coffee berries don’t ripen at the same time, it’s harder to move around in high elevation and so it can’t be mechanised.

Remember that coffee is a colonial product and often the strongest coffee markets aren’t the ones who grow it. Therefore the coffee markets also dictate what’s grown. Some coffee farmers will try and grow both: Arabica at higher elevation and Robusta at lower levels. Arabica is more often washed and therefore overall is much more labour intensive.

How should certifications affect how we taste?
There are some brilliant and robust accreditation schemes out – and some that are less thorough. The key for anyone (judges, buyers, retailers and consumers) is to take into account when looking at accreditations and certificates is to really understand the process behind the label. What’s needed to gain the certification, is it a continual process, what can producers still do that might be an area to work on or something slightly less positive, and how transparent is that? It’s one of the reasons that we try to be as transparent as possible about the process for Great Taste!

How would you approach the range of descriptions we get as judges for coffee?
Whilst it’s ideal if we have information from the producers, we won’t always have this. We can still evaluate coffees even without the information.

Does where the coffee come from have as much influence on the taste as the process?
Just like with other products, like wine or chocolate, terroir, varietals and other aspects have a huge impact on taste. The globalisation of coffee has meant that there are more and more varietals grown in different areas, meaning there are more and more variations. Within countries and even regions there are micro-variations, e.g. volcanic soil would produce a very different coffee to one grown in a different area, but could be geographically close to each other. The same goes for elevation, varietals (there are more than 6000 varietals of coffee in the world), climate – the list goes on. It’s therefore very hard to define a typical example from a particular country, e.g. an Ethiopian coffee should taste like X, a Kenyan coffee should taste like Y.

What is the type of coffee used in commercial outlets and global coffee chains – how does it taste the same?
Like many industrial food processes, the aim for a global coffee chain is a standard flavour. In essence, they’re trying to standardise the process so that all elements of natural variation, terroir and environment are eradicated from the process.

Some coffees are “better” with milk? How do you take this into consideration?
Milk adds an extra element and you start getting into questions over heat, fat content, steaming etc. Some coffees are designed to take milk and if that is specified, then judges are encouraged to try with milk in the judging room.

How long after roasting is coffee at its peak for tasting?
All coffee goes through a curve. After being freshly roasted, coffee beans are actually not in a good state to try coffee in as gases are still being released and need to settle). The time that the coffee remains in this stage will depend on the machine and roasting.
In a drum roaster, coffee beans will likely be ready 2 to 3 weeks later when the gases has settled and the coffee aromas (the volatile aromatics) are at still at their peak. From a food safety perspective, three months later a coffee will be absolutely fine to drink, however the coffee aromas will no longer be at their peak. Air drum infrared heat means that the beans don’t release their gases as quickly so you need to wait at least 3 weeks – 1 month. Winter and summer also affects this. Summer = more heat and so a faster process. This means that the supply chain relationships are so important. Your supplier needs to understand what you’re trying to achieve.