Thursday, 23 April 2015 21:40

Cupping Fundamentals

Cupping is perhaps one of the most important skill anyone can develop within the coffee industry. Initially developed by green coffee buyer, "cupping" provides a consistent methodology for evaluating a coffee's quality before determining a price on a lot. In much the same way that a wine connoisseur would evaluate a fine Cabernet, cuppers must use a strict set of tasting protocols to assess quality. 

Thursday, 23 April 2015 14:00

Anatomy of a Coffee Bean

Perhaps the single most important factor in determining coffee quality is the care taken during post-harvest processing. A single mistake can have serious implications, at times, capable of spoiling en entire batch of coffee. But before we discuss the various processing methods, lets take a look at the coffee bean itself.

Thursday, 23 April 2015 23:55

The Aroma of Green Coffee and Bell Peppers

That's right. These nitrogen containing pyrazines or specifically 3-isobutyl-2-methoxypyrazine are present in a wide range of food products including green coffee and bell peppers. 

Friday, 24 April 2015 00:30

Polyphenol Oxidase

Friday, 15 May 2015 19:26

Chemistry

How much caffeine is in green coffee beans?


There are over 60 species of coffee currently in existence, but only two are of main commercial value. Namely, Coffee Arabica or "Arabica" and Coffee Cenaphora or more commonly known as "Robusta" coffee. On average caffeine content in Arabica is 1.2% (range 0.9-1.4%) and 2.2% in Robusta (1.8-4.0%).

How much caffeine is in my cup of coffee?


Caffeine content varies widely in various beverages due to beverage serving size and beverage strength. The table below summarizes caffeine content in common foods and beverages:

Source: NCA, August 1999, www.coffeescience.org

There are number of other variables such a the species of the coffee, grind level, duration of brew, water brew temperature, etc. that greatly vary total caffeine in the final beverage.

Why is coffee "bitter"?


Contrary to popular belief, coffee is not bitter due to caffeine, but rather due to the formation of several protein containing compounds created during roasting. In fact, its been estimated that less than 10% of coffee's 'bitterness' can be attributed to caffeine alone.

What are "melanoidins"?


Melanoidins are brown colored polymetric compounds created during roasting process and responsible for giving coffee it characteristic brown hue. It accounts for approximately 25-30% of coffee's dry beverage and has been identified as a potent antioxidant, generally higher in medium color roasts.

Whats the most common method of decaffeination?


Methylene chloride (CH2Cl2) is the most common method of decaffeination, representing 50-75% of the decaf market. The method is sometimes referred to as the KVW method or European process. A large percentage of the coffee is still decaffeinated in Germany since this is where much of the technology originated.

What is chemical free decaffeination?


"Chemical free" decaffeination refers to the removal of caffeine without the use of traditional chemicals, namely methylene chloride or ethyl acetate.

There are several "chemical free" methods currently on the market with the most popular being the patented Swiss Water method, Mexican Water process, and Super Critical Carbon Dioxide method. The first two use water as a solvent used to extract caffeine from the bean, whereas the super critical method uses naturally occurring compressed CO2 gas as the solvent.

What is "naturally decaffeinated" coffee?


Naturally decaffeinated coffee is coffee decaffeinated using ethyl acetate (C4H8O2), a naturally occurring compound created during the ripening of several fruits.

Although manufactures label coffee as "naturally decaffeinated"  the truth is that the solvent is produced synthetically. In pure form ethyl acetate exists as a clear volatile liquid with a fruity smell. It is also used in a number of industries including perfumes, nail removers, and in the storage of insects (entomology).

What is OTA?


Produced by a mycotoxin Aspergillus ochraceus, OTA is short for "Ochratoxin A". Thus far, researchers have identified three distinct strains of the toxin: ochratoxin A, B and C, though only ochratoxin A has been associated with coffee.

OTA has been under extensive research over the past decade, since studies have shown to cause renal tumors in animal models. Currently the toxicity of OTA has been debated, since studies have shown its inability to form reactive intermediates in humans.

OTA formation in coffee has been correlated with poor manufacturing practices, namely: poorly stored cherries, improper drying, and rewetting of the beans on drying patios. Cases have also been found in poorly processed decaffeinated coffee samples.

Although OTA exposure from coffee is minor, it accounts for an estimated 4% - much behind its occurrence in other products, including cereals (44%), wine (10%), and beer (7%).

Thursday, 23 April 2015 20:59

Washed Processed Coffee

Once coffee has been cultivated and transported to processing stations, the next step is to remove the outer pulp from the cherry, so that the bean itself can be extracted out. By far the vast majority of the coffee processed is via the washed process, where mechanical and biochemical processes are used to remove the outer layers surrounding the coffee bean. 

Thursday, 23 April 2015 21:19

Natural Processed Coffee

Typically in those countries such as Brazil where water is not readily accessible to farms, the dry process is the preferred method of processing. In this process, the coffee goes through a cursory separation to remove any debris then the cherries are set out on drying patios for anywhere between 2 to 6 weeks.

Monday, 27 April 2015 11:07

Chemical Changes During Roasting

The transformation from raw bean to finished product is perhaps one of the more complex stages in coffee production.

If you take a lot of green beans and smell it, it hardly has any of the characteristics that we would typically associate with roasted coffee. Yet once roasted, the raw materials within the raw bean undergo a significant transformation to give rise to hundreds of new compounds that we can appreciate.

Monday, 27 April 2015 18:31

Drum vs Fluid Bed Roasters

Unlike products other food products which require minimal amounts of thermal processing, coffee undergoes a dramatic chemical changes before it even exhibits any hint of its aromatic complexity. For this to occur, we must pass the coffee over the fire, so to speak, and transform this relatively boring bean into a bean with a myriad of complexity.