Here’s the second part of our series of articles demystifying common terms used to describe coffee bean types. It’s designed to make it easier to distinguish between useful information and marketing hype about coffee beans, and also understand exactly what your'e buying.

1. Should I choose bean types based on how I make coffee?

Ideally, you should choose beans for the way you make coffee. One method can extracts flavour very differently to another, leading to diverse taste from the same coffee bean types.

This tends to be more the case with distinctive flavours than “classic” ones.. If you’re buying an all-round blend with a balanced flavoured, it’ll taste equally good with most methods. Conversely, a very fruity Ethiopian single-blend will work well made with Aeropress, but may not suit most palates as an espresso.

If you drink espresso, you’re generally safest picking house blends that are designed for espresso. Most roasters and brands have a blend that’s chosen to balance out the different flavours, and create a consistent flavour that works well with the short, intense process of an espresso machine.

Good examples of espresso blends are Allpress Redchurch, Square Mile Red Brick and Ozone Empire. If you want to stretch your budget further, good value alternatives include Starbucks House Blend, Illy illy Blend and Caffe Nero Classico.

This kind of coffee will also taste good using a drip maker, French press or other method, but you’ll also find a variety of single origins and distinctive blends will also work well. Most decent stores such as Coffee Geek and Friends, Saint Espresso and Caravan will offer recommended coffee bean types for filter or aeropress.

As always, the only rule worth following is to try beans that sound interesting made using the same method you’ll use at home, and choose based on what you like.

2. What difference does roast make to coffee bean types?

Raw green coffee beans are roasted to turn them into brown ones that can be used to make coffee to drink. Varying the temperature the beans reach during roasting significantly changes their flavour.

There are three categories of roast:

Light (around 195ºC-205ºC),

Medium (around 210ºC-220ºC)

Dark (around 225ºC-245ºC).

Within these are various sub-categories, although they tend to be more commonly used in North America.  For example, Cinnamon and New England are types of Light Roast, City is a Medium Roast, and Full City and Vienna are Dark Roasts. Outside North America, the best-known names are French and Italian, both types of Dark Roast coffee bean types.

Broadly speaking, the lighter the roast, the more of the original flavour of the beans is present, and the darker the roast, the greater the effect of the roast on flavour.  The other changes as the roast progresses include bean colour and texture, moisture content, acidity and caffeine content.

The changes to beans during roasting are complex, and picking the best roast for a set of beans is a complex art.  It's usually matched to the character of the beans, and the skill of the roaster is picking how much will get the best flavours a set of beans can offer.

Rather than choosing beans based on dark, medium or light roast, we’d suggest you choose your beans based on their inherent flavours, and take the roast they come in.

If you’ve found that you like dark roasted coffee, take a closer look at the flavours – either by tasting them carefully, or using the description on the pack or in the store. There’s a decent chance what appeals is a cocoa/nut general flavour, often with tones of chocolate. If you then look for beans with a similar profile, you may well find you prefer a similar bean roasted medium.

Conversely, if you’ve enjoyed lighter roasts, you may find you have a preference for fruitier flavours. In that case, good Central American single origin coffee bean types may also be to your taste, even if medium roasted.

Finally, some people look for a “kick” from their first cup of coffee for the day, and equate this with dark roasts. If that’s you, you may be surprised to know that light roasts have more caffeine than dark! The smokey flavour of some cheaper dark roasts is actually a sign of a lower quality bean, but the strength of flavour from the longer roasting time is overpowering the overall flavour. You might find that a better quality, less strongly roasted bean transforms your experience of your morning coffee ritual.

3. How soon should coffee beans be used after roasting?

Once beans are roasted, it takes about a week for the best of the flavours to come through to the coffee made from them. Then, about 2 or so weeks later, those flavours start to fade, depending on how well you’ve stored the beans.

So you should buy beans around 1-2 weeks after the roast date, rather than when freshly roasted.

If you have access to a decent grinder, you should grind the beans just before you use them, and ideally only grind enough what you’re making. If you need to grind more than that, try to avoid grinding more than you’ll use that day.

If you’re buying pre-ground coffee, you should still buy coffee ground around a week earlier, but try to buy as little as you can get away with before your next purchase, as ground coffee loses its flavour more quickly than whole beans.

4. Does it matter if I buy pre-ground or whole bean coffee?

If you have no space for a coffee grinder, or can’t manage the extra time/hassle of grinding your own beans, then pre-ground coffee is your only option. The difference in flavour between freshly ground beans and pre-ground is significant, but for most people it's about balancing flavour with convenience.

Having said that, a decent grinder makes more difference to the flavour of your coffee than a good coffee maker. So you if you haven't tried grinding your own beans, you may be surprised at how much better they taste.

But before you rush out to buy a grinder, you should also know that a bad grinder can really get in the way of making a decent drink. So the choice between grinding whole beans at home in a poor grinder and buying professionally ground powder from a good store is much trickier.

Our rule of thumb is that if you grind whole beans at home, invest in a burr grinder. A good manual one will cost as little as £20, and decent electric one will be around three times that.

If you can’t stretch budget or time to using a good burr grinder, our advice is don’t bother with any blade grinder or a poor burr grinder – stick to pre-ground and spend the money you’ve saved on beans!

5. How much coffee should I buy at a time?

The simple rule for making good coffee is only buy as much as you’ll get through before the coffee gets stale – around 3 weeks for beans, or a week for powder.

Vacuum-packing and other forms of modern packaging means the “best-before” date on coffee is many months. The coffee bought that way is invariably of lower quality than fresh beans or powder, and rarely if ever tastes as good, but it’s less costly and more convenient, and a good choice for many. If that’s your coffee of choice, you can start using it up to the date on the packet. But once it’s opened, the same rules apply, and you’ll start to notice a degrading of flavour within around a week.

How you store coffee makes a big difference to how long you can keep it tasting good. Once the pack is opened, keep the beans or powder in an airtight jar, and ideally somewhere dark and dry. It goes without saying it shouldn’t be near other foodstuffs with strong smells.

Many people believe that coffee beans should be kept in a freezer or fridge. As long as it’s in a truly airtight container, that shouldn’t make much difference in practice. The risk you run is moisture getting into the beans and ruining them quickly. If it helps, no professional or commercial set up we know of stores coffee in a fridge or freezer.

6. What are Washed, Natural and Dry coffee bean types?

Coffee beans start life as little red berries, known as “cherries”. The red colour means they’re ripe and ready to be picked. The coffee bean we buy is actually the seed of the coffee cherry, and processing is needed to extract the seed. Terms like Wet and Dry refer to the way the seed is removed from the fruit.

There are two common ways of extracting the seed – one involves soaking the whole fruit (“wet” or “washed”), the other is done by sun-drying them (“dry” or “natural” processing).

There’s a third approach called “semi-washed” which is a mix of the two. “Monsooning” is a variation on semi-washed, specific to India.

Washed coffee beans are often considered superior, because it usually involves more careful, hand-picking of only the ripe, red cherries. The fruit is then left in tanks for the outer layers to ferment before they’re removed by washing. What’s left are the green coloured seeds, which is what we know as “beans”. Once these are roasted, they turn the familiar brown colour.

Dry processing is the original, much older way of extracting seeds. Previously, the picked fruit was left to dry in the sun before the dry outer layers were removed by hand or machine. Today, the machines that do this hulling or de-husking can also work successfully on unripe fruit. So the reason some think dry processing is inferior to wet is that many farms simply strip the fruit from branches, regardless of whether all the fruit is properly ripe. The milling machines then extract all the beans, which can leave a mix of ripe and (less tasty) unripe beans.

Both wet and dry processing can bring out great flavours from coffee, particularly the more delicate notes such as fruitiness. However, dry processing often leads to greater variation in quality, so unless you’re buying from a place that is in close touch with its farms and processors, you’ll often find wet processed coffee bean types more reliable.

Semi-washed processing involves using soaking to remove the first outer layers, then sun-drying the fruit to remove the rest. This adds a depth to the flavour, but doesn’t change the inherent fruitiness, sweetness or other characteristics of the bean.

Monsoon Malabar coffee from India is a version of semi-washing, but the final step is for the beans to be carefully exposed to monsoon rains and winds. This creates a characteristic “heaviness”. These coffee bean types are specific to the southern states of India.

As a coffee drinker, you’ll certainly notice differences in flavour from the different processes, but the quality of the bean and how it’s roasted will have a much greater impact. Our advice is to not worry too much about how beans are processed.

7. How is coffee decaffeinated, and does it taste any good?

Until relatively recently, removing caffeine from coffee involved adding chemicals, which not only affected the flavour significantly, but also created concerns about health risks. These arose because the first decaffeination techniques used a chemical which we now know to be carcinogenic!

Those days are long gone, and decaffeination technology has moved on a lot. It’s now inherently safe, and can produce good tasting coffee. As a result, around one in ten cups sold are caffeine-free, and virtually all good roasters offer at least one decent version.

However, there’s still plenty of lousy decaf coffee on sale, and it’s impossible to tell from appearance or smell how a given set of decaf beans will taste compared to their natural relatives.

Decaffeinated coffee is rarely completely free of caffeine. US law says coffee labelled decaffeinated has had at least 97% of its caffeine removed; the EU equivalent is 99.9% of the beans by weight. A small irony is that to save costs, many manufacturers increase the amount of Robusta beans, which contain almost double the caffeine of Arabica beans.

There are 4 ways of removing caffeine from beans today, which is always done to raw green beans before they’re roasted. They all rely on the fact that caffeine is water-soluble, so involve soaking the beans in water. The differences arise because water also removes other things from the coffee which we want to keep, because they add to the flavour – such as sugar and proteins.

Two of the methods are solvent-based – Direct and Indirect. Both involve adding a (safe) chemical to the water to remove the caffeine, the difference is that in one the chemicals work directly on the soaked beans, in the other they don’t.

A third technique uses carbon dioxide gas (CO2) instead of chemicals, but is otherwise similar to the Direct solvent-based method.

The final method is probably the best-known, the Swiss Water method. This uses only water to dissolve the caffeine, adding extra steps to replace the positive ingredients lost along the way.

It’s not usually obvious which method has been used for a given set of decaffeinated beans, and firms rarely publicise it. Smaller places often use the Swiss Water method, but it’s harder to tell with larger firms, often because techniques change over time. Lavazza is an exception, explaining on its website why it uses the CO2 method. Caffe Nero has been reported to use the CO2 and Swiss Water method, Starbucks has been reported to use Direct and Swiss Water, and Costa may use a variation of the Swiss Water method called the Mexican Mountain Water method.

In case you think it’s obvious from the descriptions that the Swiss Water method is better, renowned roasters Square Mile have been quoted as saying they use the CO2 method.

One of the challenges of creating good quality decaf beans is that the decaffeination process changes the colour of the raw beans from green to brown. This means it’s much harder for roasters to judge what’s happening during roasting. Also, firms may save money by using cheaper beans to recover the costs of decaffeination.

Our experience is that good stores which care about the beans they sell generally stock good quality decaf. That’s less clear with bigger brands, where financial pressures often constrain their choices. However, regardless of where you get your beans from, there’s much less choice of available flavours if you want decaffeinated coffee.