Friday, 19 November 2010
A really good cup of coffee
First pick your coffee berries, and this is where your problems start as berries on a plant ripen at different rates. It is possible to use green, unripe, berries, but the resulting coffee is more bitter and lacks the mellow taste and aromatic aroma of ripe, red berries. The problem of course is that selecting only ripe berries is very labour intensive and cannot be mechanised, but for the best quality coffee that's what you have to do. Well..., normally. In Malaysia, "kopi luwak" or civet coffee, is produced from berries that have passed through the local palm civet, a type of cat, producing an aromatic coffee which is one of the most expensive in the world. One grower in Espirito santo has improved on this idea.
Native to the forests of the area are two type of"Jacu", seed eating birds about the size of chickens - the Rusty-margined Guan (Penelope superciliaris) and Dusky-legged Guan (P. obscura). Jacu are very selective in their feeding, only picking ripe berries, which in due course pass through the bird. Thus if you collect the droppings from a Jacu, you should have only ripe berries. It sounds bizarre, but Jacu coffee has regularly won prizes and is one of the most highly prized coffees in the world. I can testify that it makes a very mild, delicious brew.
Most coffee however is made without the aid of Jacus. After picking there are more or less two options, the wet and dry methods. Most of Brazil uses the dry method. Harvested berries are cleaned and debris and damaged berries removed, sometimes by passing through a flotation channel where the ripe berries will sink and the damaged ones float away. Ripe fruit are then spread out to dry, turning regularly to give even drying and avoid mildew. In many old manor farms in Brazil you can still see the large brick area where this took place.
This stage is very important in the final taste of the coffee and traditionally drying took about 4 weeks to reach the right stage - too dry and the beans become brittle and don't handle well later, too wet and they are prone to rot. Nowadays, many plantations use machine drying to give a more controlled result.
Dried fruit are then send to a mill to remove all the remaining fruit residue, leaving just the coffee bean. Sometimes the beans are then aged, potentially for up to 8 years, but most experts seem to agree that flavour peaks at about a year after harvest. The last important stage is roasting, which normally takes place in a rotating drum heated from below to between 180 and 280 C. Coffee with delicate flavours are only roasted for a few minutes, but roasting itself endows a strong flavour which is also popular. Beans are then cooled (air cooling is much better than water) and then the last stage is grinding, which for optimum flavour should take place just before use.