Ponder, for a moment, the coffee plant. Done pondering? Good.

Inside the ripe red cherries of this bush lie the beginnings of great coffee: the green coffee bean. The weather, the soil, the irrigation - everything affects the flavour.

In fact, from soil to roaster, there's a complex list of factors which affect the quality of beans. And that's before we even think about grinding and extracting.

Getting it right takes care, attention and expertise - and those cost. In other words, good green beans don't come cheap.

Take shade, for example.
Healthy coffee bushes need to be shielded from fierce sunlight. This doesn't involve embarrassing hats and mirrored sunglasses. It does involve nestling the coffee bushes beneath natural shade, like banana plants. They not only protect the valuable bushes, but provide the farmer with another crop and source of income.

Even the wildlife wins - as the trees are a perfect home for migratory birds. Growing this way rules out mechanical harvesting - so costs are high. But we reckon it's a price worth paying.

The age and condition of the coffee bushes is vital too. Most plants don't start producing a usable crop for at least 3-4 years, and many farmers believe that after 10 years the crop just doesn't taste as good.

During that short period of time when the bushes are at their best, they need to be harvested the right way. The cherries need to be picked when they're perfectly ripe, and that means revisiting the same bushes again and again. If the cherries are too ripe, the coffee will have a nasty, fermented taste - if they're not ripe enough they'll taste sour and bitter.

As only the perfectly ripe beans will do, mechanical "strip picking" just doesn't make sense when you need to revisit the bushes.

No trouble at mill
When farmers take their crop to the mill, it's weighed and checked for ripeness - the best beans command a premium. Then the cherries need to give up those valuable beans. There are different ways of doing this, and each lends the beans a different character.

Dry
Imagine the biggest patio you've ever seen (minus cheerful gnomes and ornamental fountain). Then imagine a thin layer of coffee cherries being raked over it, drying under the searing sun for 2-3 weeks.

The beans are then put through a hulling machine to remove the remaining fruit as well as the parchment which surrounds the bean (it's like a thin shell). This part of the process is tricky - if the machine is too harsh, the beans will get damaged. But if it's too gentle, there will be lots of parchment left on the beans - bad news when it comes to roasting.

Dry coffees are usually smooth, with lots of body and a distinctively earthy taste.

Wet
The cherries are pulped in a machine, then washed in tanks of water - which is where they gently ferment. This bit is vital - too long in the tanks and the beans will be distinctly stinky. Not long enough and they'll be salty and sour.

Then the beans are washed again. Many forward-thinking mills recycle this water, by using reeds to soak up the impurities.

The beans are then dried - sometimes using driers fuelled by burning old coffee bushes or the parchment from cherries. Again, this process has to be closely monitored. If the beans are dried too much, the flavour gets dulled.

Finally, the beans are held in large containers to help equalise the moisture content - vital for precise roasting.

In the main, wet coffees command a higher price - they have a cleaner flavour, with a pronounced fruity taste.

This article originally appeared in Fresh 17