Course:FNH200/Projects/2020/Coffee

Introduction, Background and History

Introduction

In 2011, coffee was the second most consumed drink in the world, trailing behind water (Butt, 2011). With almost 16 million kilograms of coffee produced worldwide in 2016 and over US $10 billion in trade, the demand for coffee has increased exponentially over the last few decades (Sisay, 2018; Butt, 2011). As of 2018, Ethiopia recorded an approximate annual production increase of 3.6% since 1990 (Sisay, 2018). From mochas to lattes, caffeinated and decaffeinated, coffee offers versatility to its millions of consumers. Coffee is often consumed because of its heavy caffeine content which ranges between 0.9- 2.4% in dry weight (Severini, 2017). As a natural stimulant, it stimulates the central nervous system, effectively increasing alertness and decreasing drowsiness (Butt, 2011).

Background and History of Coffee

Many critics consider Ethiopia to be the center of origin and diversity for Arabic coffee because Coffea arabica, the wild coffee plant, originates from a small region in Ethiopia (Sisay, 2018; Smith, 1985). While the first species of Coffea is said to have been discovered in about AD 859, there are now over 100 species known to date (Smith, 1985). Having said that, Coffea arabica is the most widely produced and sold species, as it has a richer, less acidic taste than Coffea robusta, which comes in second (Sisay, 2018). Over time, the production of coffee has adapted from solely forest production to what we see today which is forest, semi-forest, plantation and garden production (Sisay, 2018). This has allowed coffee production to spread throughout countries in Africa, South America, Australia, Asia and North America (Szenthe, 2019).

Coffee Treatment

Processing

Coffee trees bear fruit in the form of coffee cherries, which are bright red when ripe. The cherries are processed by one of two methods. The more common method is wet processing, which involves passing the cherry through a pulping machine that removes most of its skin and fruit. The remains are put into a water tank for 12 - 48 hours to ferment. Once removed, they have fermented into coffee beans and are rinsed and dried until they contain a moisture content of 11% (Vos, 2018).  The other method is dry processing, which involves laying cherries on tarps until their moisture content is reduced to the required 11% ("10 Steps from Seed to Cup", n.d.). Since this process can take weeks to complete, it is not commonly used. Before exporting, these newly dried beans must be hulled or the outer layer of the bean must be removed. Sometimes the remaining silver skin on the bean is removed afterwards in a process known as polishing.

Manufacturing

After the coffee beans are polished, they are placed on a conveyor belt that passes workers who remove any sticks and debris that may be present. They are then graded based on size, location of plantation, drying and husking methods used, and taste. Finally, coffee beans of different grades are packed and prepared for transport to fulfill orders received by various roasting companies.

If previously harvested from tropical, humid, or other undesirable conditions the beans must be shipped quickly to avoid spoiling. Once packages are received by roasting companies, the beans are roasted in a metal cylinder filled with circulating hot air in bulk. It must be noted that coffee beans are not always shipped to roasting companies. In some cases, stores receive beans directly from suppliers to roast for consumers on demand, maximizing freshness and product quality.

An alternate, older method of roasting entails placing the beans in a metal cylinder that is rotated over an electric, gas, or charcoal heater (Myhrvold, June 2020). Roasting gradually raises the temperature of the beans to a temperature range between 220°C and 230°C, regardless of the method used (Myhrvold, June 2020). This triggers the release of steam, carbon monoxide, and carbon dioxide, thus reducing the original weight of the beans by 14 to 23% (Myhrvold, June 2020). The pressure of these escaping internal gases causes the beans to swell, increasing their volume from 30% to 100% (Myhrvold, June 2020). As a result of this process the color of the beans darken, a crumbly texture is produced, and chemical reactions imbue the coffee with its familiar aroma (Myhrvold, June 2020).

After roasting, the beans are placed in a cooling vat, where they are stirred while cold air circulates around them. High quality beans are sorted through an electric sorter that eliminates any beans that are too light or dark in color. The now roasted coffee beans are then packaged for retail, either as they are or pre-grounded as specified by the order.

To produce instant coffee, for instance, coffee is brewed and boiled down to a concentrate. The concentrated liquid is then sent through a spray drying tower, which is shown in Figure 2. The tower pumps the concentrates through an atomizer turning them into small droplets ("All about Spray Dried Coffee", n.d.). The falling droplets lose their water content rapidly as they come in contact with drying gases.

Different Types of Coffee

Coffee, a popular commodity across the world, has multiple variants. One variant is Black Coffee, which is brewed only from coffee grounds. Black coffee is low in calories, fats, carbohydrates and potassium (Nahida, 2019). For instance, an 8-ounce cup has 0% fat, cholesterol, sodium, carbohydrates, sugars, and 4% potassium, therefore it may be a good alternative to sweeter variants of coffee (Nahida, 2019). The addition of  sugar, milk, cream, or additives to black coffee would impart flavor as well as calories, which is not favored for some who enjoy its strong bitter taste (Nahida, 2019).

Another example of a variant is Cappuccino, which was invented in Italy in the early 1900’s and adapted by other countries (Goodwin, 2020). The current-day regular cup of cappuccino has  ⅓ espresso, ⅓ steamed milk, ⅓ airy foamed milk ("Cappuccino vs Latte: Both Use Espresso, So What's The Difference?", n.d.). Although similar to a latte, the cappuccino has more foam and less milk that is not mixed with its espresso portion ("Cappuccino vs Latte: Both Use Espresso, So What's The Difference?", n.d.).

Latte is another type of coffee invented in Italy. It is made from a combination of steamed milk, espresso, and foamed milk. A latte consists of  one shot of espresso mixed with 6-8 ounces of steamed milk then topped with lots of foamed milk (Papazian & Pritikin, 2019), which makes it much milkier than a cappuccino (Goodwin, 2020).  The main difference between a cappuccino and a latte are the ratios of their common ingredients ("Cappuccino vs Latte: Both Use Espresso, So What's The Difference?", n.d.).

Storage and Preservation

To prevent coffee staling, it is crucial to keep coffee beans, ground or whole, in a dry airtight container (Goodwin, 2019). If possible, coffee should avoid areas with moisture, heat, and light, as all those factors negatively impact the preservation of coffee (Goodwin, 2019). First, light breaks down organic cell structures through the process of photo degradation (Oden, 2020). Additionally, with every 10°C increase, chemical reactions, specifically oxidation reactions, happen twice as quickly ("How to store coffee beans (and tips for freezing coffee beans)", n.d.). Therefore, these reactions caused by heat encourage the growth of microorganisms (Oden, 2020). Besides heat, humidity promotes bacterial growth, along with altering the moisture level of the coffee beans, which negatively changes the flavour (Oden, 2020). Coffee’s hygroscopic nature makes it easily absorb moisture and odors around it, causing its original flavors to change ("How to store coffee", n.d.).

The best containers to maintain quality coffee beans are an opaque glass, ceramic, or non-reactive metal container with an airtight gasket seal (Goodwin, 2019). With these types of containers, those previously-stated limiting factors will have no effect on the beans. It is recommended to avoid storing coffee beans in a fridge, even though refrigeration is a form of food preservation, since it is not cold enough, the coffee beans will absorb the aromas in the fridge ("How to spot freshly-roasted beans", n.d.). Furthermore, a fridge causes coffee to condensate and push oils to its surface, expediting its aging process (Goldberg, 2015). Although freezers are not recommended as storage places, if used, ensure that the coffee beans thaw to room temperature completely, or condensation will occur (Oden, 2020), leading to freezer-burn (("How to store coffee beans (and tips for freezing coffee beans)", n.d.), loss of moisture in solid and liquid foods through evaporation.

The storage and preservation of coffee beans differs for whole and ground coffee. Regardless of the beans that are used,  maximum freshness is achieved within 72 hours ("How to spot freshly-roasted beans", n.d.). Whole beans lose significant amounts of flavor within two weeks of roasting, compared to ground beans that lose significant amounts of flavour within two days ("Coffee packaging and shelf life issues", n.d.). Figure 1 shows the change in freshness for ground beef ("Coffee packaging and shelf life issues", n.d.).  Therefore, it is recommended not to store ground coffee, and to store a maximum of one week’s worth of whole beans if you want to maximize freshness ("How to spot freshly-roasted beans", n.d.).

Storage and preservation of coffee beans differs for whole and ground coffee. Regardless of the beans used, maximum freshness is achieved within 72 hours after roasting ("How to spot freshly-roasted beans", n.d.). Whole beans lose significant amounts of flavor within two weeks of roasting, and ground beans within two days ("Coffee packaging and shelf life issues", n.d.). Figure 4 shows the change in freshness of ground coffee over time ("Coffee packaging and shelf life issues", n.d.). Therefore, it is recommended to store a maximum of one week’s worth of whole beans and not to store ground coffee for longer durations if optimum freshness is desired ("How to spot freshly-roasted beans", n.d.).

Health Benefits and Detriments

Health Benefits

When taken in adequate amounts, coffee has more benefits than harms with the greatest reduction in health outcomes seen at 3-4 cups of coffee a day (Poole et al., 2020). Meta analysis research indicates an inverse association between coffee consumption and a reduction in cardiovascular diseases, specific cancers and neurological, metabolic, and liver conditions (Poole et al., 2020). Coffee is a complex chemical mixture that is rich in several bioactive molecules including chlorogenic acids, caffeic acids, and melanoidins; principal polyphenols (micronutrients) that have a potent antioxidant effect (Wolde, 2014). Antioxidants help reduce oxidation reactions, which reduces damage to body tissues and protects against these undesirable health outcomes (Wolde, 2014). In particular, polyphenols improve by helping treat digestion issues with weight management difficulties and thus lowering the likelihood of developing diabetes and cardiovascular diseases (Bidel & Tuomilehto, 2013).

Health Risks of Coffee

Excessive consumption of coffee over long periods of time has been shown to pose various long term health risks to individuals (Higdon & Frie, 2006). Excessive consumption has been found to be directly correlated with an increase in numerous cardiovascular disease risk factors, blood pressure, plasma homocysteine, and is associated with increased risk of coronary heart disease and heart attacks (Higdon & Frie, 2006).

Food and Drug Regulations (FDR) of Canada: Composition standards for Coffee

Coffee is described as a separate entity under DIVISION 5, Part B, of the FDR. It categorizes green coffee (raw and unroasted coffee) into 3 types; Coffee arabica L., C. liberica Hiern, and C. robusta Chev (“Food and Drug Regulations”, 2020). The regulations highlight that roasted coffee should be roasted green coffee, and shall not contain less than 10% fat, and may contain no more than 6% total ash (“Food and Drug Regulations”, 2020). Decaffeinated should indicate the type of the coffee from which caffeine has been removed by means of extraction solvents (in Table XV in DIVISION 16) and that contains not more than;

• 0.1% caffeine for decaffeinated coffee and decaffeinated raw coffee (“Food and Drug Regulations”, 2020)
• 0.3% caffeine for decaffeinated instant coffee (“Food and Drug Regulations”, 2020)

Exam Question

Which drying technique is used in the production of instant coffee?

A) Tray drying

B) Spray drying

C) Drum drying

D) Deep fat frying

Correct Answer: B

In the spray drying section of module 8.4 it mentions that coffee is commonly dehydrated in this manner.

This question helps to reinforce the different purposes of each drying technique. For liquids such as concentrated coffee, spray drying is effective and used in manufacturing.