Almost everything you wanted to know about green coffee beans!
Here's a quick review for your Home Coffee Roasting edification!
The four main sections below are:
-What is green coffee?
-What are the processing methods of green coffee, such as natural (dry), washed and semi-washed?
-How do I describe what I'm tasting?
Green Coffee Beans are actually the seeds from the fruit of
Fresh coffee beans are
green when removed from the fruit of the tree. It is the roasting
process that changes them from green beans to the various shades
of brown, depending on your roast preference. So in the industry,
Green Coffee simply means unroasted coffee beans (that are ready
Click here to
review our offering of fine green coffees.
There are two main species of coffee trees:
- Arabica - the source of our premium specialty coffees
- Robusta - a heartier, more prolific tree, with higher
caffeine (unfortunately it often has a rubbery, flat taste)
While some coffee blends do contain beans from the Robusta tree (to add caffeine, body and crema). In general, specialty grade single origin coffee comes from the Arabica plant.
The SCAA standard for Arabica Coffee is subdivided into 5 grades, distinguished primarily by the number of "defects" the coffee contains per pound. For example, grade 1 coffees must have less then 5 twigs, or broken or discolored beans, etc. per pound. In general, the coffees here at Burman Coffee Traders are grade 1 Arabica, the best coffees available.
However, sometimes we discover an excellent coffee from a region that grades their coffee differently, i.e. that contains a higher number of broken beans, etc. The Yemen Mochas and some Ethiopians are such coffees. (top)
Processing Methods of Green Coffee
Before they can be roasted, green coffee beans must be separated from the moist, sweet cherry pulp and inner hulls, then cleaned and dried. This series of steps is known as processing or preparation (prep). The main processing methods are known as natural (dry), washed and semi-washed.
The method used for preparing beans has a dramatic effect on coffee flavor, as we’ll see below. Also, preserving the subtle, intense cup quality of Specialty beans requires processing steps far beyond the simple hulling and drying needed to prepare other coffees, seeds and grains for their markets. These extra steps, directed by expert quality management, add significant expense and value to specialty coffee beans.
Natural or Dry Processing (top)
The traditional way of preparing coffee beans for market, it is the preferred method for many origins, especially where water is at a premium. At its most basic, ripe cherries are spread on the ground in the sun. When the fruit is dry, it’s pounded and winnowed to separate the beans away from the dried fruit and hulls; they’re then graded, weighed and bagged.
In terms of appearance, the presence of fruit pulp during drying and the pounding during cleaning mean that Natural beans are pretty varied in color and shape. Many technical quality improvements have been incorporated to prepare Naturals for the specialty market - drying patios of gravel/cement instead of earth, or elevated racks to facilitate quicker drying. Also, machinery is now commonly used to hull, separate and clean the dried beans. The result is cleaner cupping specialty Naturals with beans that have a more consistent appearance.
In the cup, Natural coffees exhibit heavier body and flavor profiles with deeper-toned and more varied fruit, chocolate, spice and savory notes than the same beans prepared by the washed method. These coffees add depth and authority when used in blends. Natural coffees tend to have more chaff when roasting.
Washed or Wet Processing (top)
Wet processing, with its improved physical consistency, cleanliness and appearance of coffee beans, developed during the Industrial Revolution to facilitate advances in technology. It requires abundant water resources, and was pioneered in the tropical uplands of the New World.
Washed processing has 2 stages. The first “wet milling” stage starts with several washing and brushing cycles to separate the sweet pulp completely from the hull encasing coffee beans known as ‘parchment’. Next, the cleaned parchment soaks in concrete pools for several hours, allowing chemical changes that develop beans with very clean and bright flavor profiles. They are then dried; either by the sun on cement patios, or mechanically in huge rotating heaters called gardiolas.
In the second “dry milling” stage, the beans pass through a series of machines: they’re hulled and de-chaffed; graded by high-speed sorters to regularize size, color and/or density; then weighed, bagged and marked for shipping. The extremely consistent size, shape, color and flavor of beans processed by the washed method facilitates larger batch sizes and longer, darker roasting with less fire danger.
In the cup, washed coffees exhibit bright, clean flavor and aroma, with notes of fruit, citrus, floral and spice. Flavor is mainly perceived from tongue-tip through mid-mouth and up into the sinuses. Washed coffees have light to medium-heavy body, and provide a blend’s crisp, vital first impression.
Semi-dry or Semi-Washed Processing (top)
A hybrid process used in Indonesia, Brazil and other origins with abundant water, it is used to improve the flavor and physical consistency of Natural coffees. It is used mainly for Specialty-grade beans due to its higher expense.
The process begins with removal of the outer cherry using wet pulping machines. The beans, still coated with sweet pulp, are ‘rested’ - cured for up to a day to develop the characteristic ‘Natural’ flavor profile. The pulp is again rinsed and the parchment coffee, still with traces of pulp, is fully sun-dried. Grading, weighing and bagging is accomplished in mechanized dry mills, similar to those used in wet processing.
By gently removing most of the fruit before drying, controlling the amount of pulp contact during drying, then using mechanized dry milling – coffee flavor, and especially its physical consistency, is greatly improved. The beans retain the same flavor and body as Natural process coffees.
The Taste of Good Coffee
Specialty coffees can be further distinguished by a number of interesting taste and aroma characteristics. These are
not necessarily on a scale of good to bad, but rather differences
that accommodate individual taste preferences plus providing a
pleasing variety of experiences available. Quite often these taste
and aroma differences are tied to a certain world region, where
altitude, sunlight, average temperatures, moisture, and a variety
of regional environmental differences produce different taste
characteristics from the same kind of coffee tree.
At Burman Coffee and on BurmanCoffee.com we use the following taste characteristics to help describe the differences among our coffees.
Brightness (acidity) (top)
Acidity, or brightness, is the first impression of a cup of coffee - that crisp sensation at the tip of your tongue. It’s important to know we’re talking in terms of perceived acidity here, not pH; coffee is actually less acid then most soft drinks.
We perceive pleasantly acid flavors almost instantly on the tongue’s tip and front corners, and just behind the upper teeth. Trace amounts of various acids found in coffee - Citric, Lactic, Malic, Acetic and a dozen or so others – also contribute many different bright, snappy flavor notes.
Beans grown at higher altitudes and processed by washed methods generally have greater perceived acidity then lower-grown or naturally-processed beans from the same origin and region.
During roasting, heat causes acids to be formed and consumed, converted into sugars and other flavor compounds. Roasters manage roasting time, roast profile and outturn temperature as methods of controlling acidity, balancing it with body, and providing flavor notes. Some examples:
- Dark roasts have lower acidity then lighter roasts of the same origin;
- Origins or blends roasted on short roast times cup brighter then the same origin/blend roasted to the same level on longer times;
- Internal changes to a roast profile also changes relative levels of acids in a coffee, resulting in a cup with significantly different flavor notes.
Take a sip of coffee. Ask yourself - how full of flavor does my mouth feel, and for how long? Along with perspective gained from hundreds of tasting trials, that’s how cuppers and roasters learn to evaluate body. Laboratory testing quantifies components of coffee related to body - levels of viscosity, oils, sugars, dissolved solids such as cellulose, suspended particles, etc. – but comprehensive sensory evaluation is a matter of perception and practice.
Using a consistent brewing method for evaluating coffees has a profound effect on coffee’s body level and flavor profile. Coffee brewed by French press or cowboy-style shows a more complete flavor profile and significantly fuller body then the same coffee drip-brewed with a paper filter - the filter traps oils and solids that are part of body, and fine particles that carry darker flavors.
Green bean processing methods also dramatically affect a coffee’s body. Washed processing removes the sugary fruit pulp completely from coffee beans, producing coffees with light to medium body and very clean, bright flavors. Natural processing, in contrast, dries beans and fruit together to produce coffees with deeper-toned, more diverse flavors and heavier body.
Roasting also affects body. In general, longer roasting times build a coffee’s body, while shorter times accent its acidity. This, however is true only to a point; too long a roast causes a coffee to lose both acidity and body, a fault known as baked or bakey.Bakey coffees brew a cup that’s insipid and lifeless.
Varietal Characteristics: In addition to body and acidity
or dryness, a good specialty coffee imparts several distinctive
flavor and aroma characteristics. These flavors may be bold or
subtle and helps further hallmark a particular coffee. (top)
Seasonal Variations: Like fine wine, the taste of particular region and grower's coffee can be affected by weather. Coffee is a crop that varies by season, and by region, depending on the conditions present during that growing season. Our job is to uncover where the best coffees are being grown at any moment in time, and select the best lots from that region.
One of the many advantages of home coffee roasting is, that green coffees will keep for a year or more. Thus, when you find a particular coffee that you especially like, you can order a larger quantity and keep it around, and roast it fresh for special occasions. (top)
The Burman Coffee Traders Selection
The first step we take in acquiring new coffee is to eliminate the ones that have any negative characteristics. You won't find any bitter or sour or rubbery tasting coffees here. Then we decide if this coffee is distinctive enough to stock. Our goal is to provide a broad selection of the best examples of the classic coffees from the world market. We often go through many samples of outstanding coffees from different sources just to find right lot.
We supplement our selection of classic coffees with high quality decaffeinated coffees and organic/shade coffees. Incidentally, many of our decaffeinated coffee drinkers, have found our freshly home roasted decaffeinated coffee beans produce a coffee light years ahead of any decaffeinated coffees they have experienced.
We always make a special effort to support those growers who produce excellent coffees and provide fair wages and conditions to their workers.(top)