A guide to filter coffee: Processing and brewing methods, roast levels and grind size
A good filter coffee lets you experience the beautifully unique nuances of your cup. That can be floral notes, fruity notes or pronounced acidity. To brew a great filter coffee we need to dive deeper into the different brewing methods, roast profiles, processing methods and grind sizes that let the coffee’s characteristics shine.
Brewing methods for filter coffee
Drip coffee – Pour over and batch brew
Think V60, Chemex, Kalita, Moccamaster ...
Drip coffees are prepared by simply pouring hot water over a bed of ground coffee. This pouring action is either done manually (pour over) or with the aid of an automatic coffee maker (batch brew).
Both, pour over and batch brew, allow gravity to draw the water through the coffee bed and filter the extracted coffee into a vessel. The hot water and the coffee grounds are in contact for a shorter period. The water extracts the coffee’s solubles and oils in a constant flow without clogging the paper filter (provided you have the correct grind size). We talk about grind size in a minute.
Based on the brewing device and paper filter thickness, filter drip coffees catch nearly all of the extracted oils and ultrafine particles. The result is a cleaner cup with a lighter mouthfeel which lets the coffee flavours and acidity shine.
Because of the drip coffees’ ability to highlight the subtle nuances of the coffee, this brewing method is well suitable for using a lighter roast profile.
Think plunger coffee, AeroPress, Clever Dripper …
These coffee brewing devices use a full immersion technique. That means the coffee grounds are fully immersed in water extracting the coffee’s solubles and oils over a longer time. The eternally popular plunger-style coffee uses a metal filter to separate the extracted coffee from the coffee grounds and allows its natural oils and fine particles (sediment) to pass through into your cup. This gives plunger coffees a richer and bigger mouthfeel but makes it harder to experience more subtle sensory notes.
Whatever your preferred filter brewing method, it won’t change the flavour of your coffee, but will affect how different flavours are accentuated and shine through.
Roast profiles: Light or medium
Which roast profile accentuates the coffee's subtle sensory profile best?
Lighter roasted coffee beans aim to accentuate the coffee’s quality and its intrinsic sensory profile. Coffee beans are roasted for a shorter time and are less porous than coffee roasted to a darker roast level. This means the coffee’s solubles, the tasty bits, extract more slowly. That’s why lighter roasted coffees are best suited to slower extraction methods such as in pour over, batch brew and plunger-style coffees and are less suited to espressos.
Of course, you can enjoy a filter coffee using a medium roast profile. A medium roast profile will give you a sweeter, more comforting cup with more body.
After all, beauty lies in the eye of the beholder, and we believe that applies to coffee too. As a rule of thumb, drink the coffee you enjoy, the way you like it.
Processing methods: Natural-processed vs washed coffees
Which processing method lets you explore the coffee's intrinsic characteristics best? Well, that depends on the characteristics you’d like to explore.
Natural-processed coffees have the ability to display a diverse range of fruit notes. That’s because after the coffee cherries have been harvested, they are left intact and spread out to dry in the sun. That allows the beans inside the coffee cherries to draw in all those yummy fruit flavours and sweetness from the surrounding fruit flesh.
Washed coffees are known for their pronounced acidity and often floral notes. In the washed process the outer skin and most of the fruit flesh are separated from the coffee bean in a procedure called de-pulping. The coffee is then moved into fermentation tanks with clean water where the remainder of the fruit flesh is removed by fermentation.
Which grind size is best for filter coffee?
The grind size for filter coffees often determines whether you get a good or a bad cup.
Ever wondered how the tasty bits of coffee beans end up in your brew? The key is extraction.
Coffee extraction can be simply described as the process during which water infuses the roasted ground coffee and passes all the tasty (and sometimes not so tasty) bits into our cup. Now, not all the mass of the coffee bean is soluble when it comes into contact with water. Only an estimated 30% are soluble and of that 30 % only 2/3 are considered good solubles, so the tasty bits we want to extract.
Solubles are extracted at different times during the extraction process. Fortunately, the ‘bad’ solubles, the not-so-tasty ones, take a longer time to dissolve and therefore are released last. If the grind size is too fine, your paper filter will clog up in drip methods. That means your coffee grounds are in contact with the hot water for a longer period, and you’ll probably end up with a bitter brew. To avoid this, grind a bit coarser. Or simply try to brew smaller batches. Also, you may want to try hotter water to extract solubles faster and avoid clogging the filter.
Now, what happens if you have a too coarse grind size for your filter coffee. You don’t give your ground coffee and water sufficient contact time to extract enough tasty solubles and end up with a watery, sour-tasting brew.
We typically grind plunger coffee very coarse and drip coffee to medium-find grind size.
HAPPY FILTER COFFEE BREWING!