B-TIP – PROCESS PT.1 – THE BASICS
Let’s have a conversation about process.
Process hugely influences the flavour of our coffee – but how exactly? The coffee ‘beans’ that we drink are in fact the seeds of a piece of fruit, referred to as a ‘coffee cherry’. How this seed is removed (or processed!) dramatically changes the cup qualities of the end product.
The two main processes are wet (or washed) and dry (or natural). We can very basically liken the difference in cup notes between the processes to fresh and dried fruit. Think of a grape – a fresh, green grape has bright acidity alongside a lovely fruity sweetness, leaving your mouth watering with a crisp finish. A dried grape (raisin) still has acidity but it tends to be more jammy, with a deeper more molasses-y sweetness and a textured finish.
We’re running a pair of almost identical Ethiopian coffees in the coming months where the only difference is the way the coffee has been processed – keep process in mind as you’re tasting these coffees.
So how do these processes work, I hear you ask?
WET (WASHED) PROCESS
The specifics of this process differ a little from country to country, but here’s a basic run through:
- Picking and sorting: Perfect fruit makes perfect coffee. A floatation tank is often used to separate under ripe or damaged coffees; the good stuff sinks and the poorer quality coffee floats.
- Getting the seeds out: The coffee that passed the sorting process goes into a wet pulping machine, which squishes the fruit to separate the skin & flesh from the seeds.
- Fermentation: The skins & flesh are discarded, and the seeds are placed in a water bed to undergo wet fermentation. The period of ferment can change country to country. This serves to remove any remaining flesh from the seeds, as well as influence flavour.
- Drying: The coffee at this stage needs to be dried down to an appropriate moisture content; around 11%. Many farms will dry their coffee in the sun, but some also use mechanical driers.
DRY (NATURAL) PROCESS
Dry process coffees differ to the wet process above:
- Picking and sorting: As above, the quality of the fruit is paramount to the flavour of the end product. A flotation tank usually isn’t used in this process, so the coffee is hand sorted for ripeness and defects both before it goes out to dry & after hulling.
- Fermentation & drying: You guessed it – no water here either. Natural coffees undergo a whole cherry dry fermentation under the sun, where the sugars from the fruit ferment and are in contact with the seed for the drying period. As above, these coffees are dried to around 11% moisture content.
- Getting the seeds out: After drying, the whole coffee cherry is quite brittle. This coffee is ‘hulled’ using a machine that cracks the outer layer of dried fruit & skin, leaving us with just the seeds. Density tables are also used to grade the coffee after hulling.