Most of the world's beans are graded by size - too small and they'll burn in the roaster, too large and they won't develop much flavour. They're sorted by using a large vibrating table. This helps ensure the selected beans are all very similar in size. Pale, broken, crushed or simply sub-standard beans need to be whittled out - usually by hand, but increasingly by using optical sorters, which are expensive but very effective. All this effort culminates in a roasting and cupping at the mill - which checks for obvious problems like secondary fermentation - and finally, the green coffee beans are ready for the market. Try before you buy Before we buy beans, we get a sample from the mill - which we brew and taste to pick out flavour characteristics. It's a case of making sure the coffee we're going to roast will taste great - before committing to buying the whole batch.

In fact, we taste the coffee at least four times before we put it into our main roasters. It's this constant testing which almost completely guarantees we don't have to turn away coffee because it's not good enough.

So everyone wins - we get great green beans, you get great coffee and farmers get the reassurance that we're happy with their shipment.

Raising the standard
There are several ways of controlling how green coffee is produced: the Ethical Trading Initiative, Fairtrade and organic.

For us, taste is everything. So it's good to know that ethically traded coffee and organic farming don't compromise the uncompromisable.

Ethical Trading Initiative
The Ethical Trading Initiative (ETI) does things like make sure the work environment is safe, with clean drinking water and proper sanitation. They also ensure that children aren't exploited, and that workers can join a trade union - and that's just a small selection of the rules.

ETI is also about traceability - which means tracking the beans through every stage, right back to the farm they were grown on. The result is that we now work even more closely with farmers, which creates trust and a culture of constant improvement.

Fairtrade
Fairtrade is about making sure farmers get a fair and sustainable price for their crop - a price that's fixed in advance above the costs of production. This helps people plan for the future, and avoid being hurt by price fluctuations in the world coffee market.

Organic
Organic coffee also helps farmers - they get a higher price for their coffee, which they can use to invest in even better facilities. However, it's a big decision for them to make - organic certification takes at least two years.

It also means we need to purge our roasters by putting through two lots of organic beans which we have to throw away, before roasting up a full batch. But we think it's worth it - organic farming promotes sustainable farming methods which are better for the environment.

This article originally appeared in Fresh 17