Debris in green coffee is an unfortunate fact of life. It's mostly
due to the realities of the whole process of picking and preparing
coffee for shipment. First, when coffee is picked, leaves and twigs
inevitably end up in with the coffee cherries. Then, depending on
how it is processed, either the dry coffee cherries or the wet,
washed hulled coffee beans end up spread out on vast concrete pads
to dry in the sun. In some of the poorer countries they are simply
laid out on tarpaulins on the side of the road.
Rocks, seeds, bird poop, clods of dirt etc. can all get mixed in
with the green beans. It doesn't really affect the green coffee,
because at this stage of the processing the beans are still enclosed
in a sort of hard seed case called parchment. It's only when the
beans are sufficiently dry that they are put through a machine to
remove the parchment and into bags or containers for shipping.
This step removes most of the rubbish along with the parchment
fragments, but some bits of junk still get through. They are
predominantly small rocks, some seeds (including corn, which is
often processed on the same pads) and the odd twig. However, all the
junk has one thing in common, it's about the same general size,
shape and colour as a green coffee bean.
The bit in between when the parchment is removed and the coffee is
bagged can also lead to contamination with man-made junk like bag
staples, nails, bullet casings (true!), personal jewelry and the
like, involuntary contributions from the people who do the work of
bagging and loading the beans.
When the roaster (that's us) gets the beans we have no way of
knowing what lurks in each bag, so we just weigh out the beans and
tip them in to the roaster. One thing that you can be sure of is
that coffee coming out of the roaster at 215°C is absolutely
sterile, and that most organic junk (seeds, twigs etc.) has been
burned away. Funnily enough corn survives and pops, and fresh coffee
flavored popcorn is very nice.
The roasted coffee then goes through a machine called a de-stoner,
basically a monster vacuum cleaner with just enough suck to lift up
roasted coffee beans and not enough to grab rocks and metal. A
magnet in the destoner gets most ferrous metals anyway. Like most
machines, though, the destoner isn't perfect.
Small, light rocks (basically pumice) that weigh about the same as a
roasted bean can get through the processing and end up in your bag
of coffee. Normally they are harmless, but every now and then a
slightly harder one can jam up a domestic grinder. Unfortunately we
have no way of making sure that this never happens despite our best
In the end, our last line of defense is the good old mark-1 eyeball.
Popcorn is white and pumice is generally light grey and can be
spotted when we're weighing the beans before putting them into the
bags. If we see a rock, we pick it out. The popcorn gets eaten.
Coffee is a seasonal product, which means that the very best coffees
will only be available once or twice a year. This will be the last
time you'll see this coffee until about March or April next year, so
Costa Rica Tarrazu Miel
Rich coffee aroma, with sweet acid, smooth fruity mid palate and
creamy body, the coffee-est coffee you'll ever taste.
Until next month