1. In what places was coffee first discovered and then cultivated? What are some of the legends of the origins of its roasting and brewing?
Coffee was first discovered, according to legends, by the Abyssinian shepherds who consumed the seeds of some Coffea plant. The appeal of the coffee mostly likely had to do with the physiological effects of the caffeine that they experienced.
The ripe cherries are usually picked by hand and then either lay out in the sun for drying or depulping. This releases two seeds per fruit, which are the coffee beans.
According to Wikipedia, Coffee was believed to have been discovered in Ethiopia. It then spread to Egypt and Yemen. (http://en.wikipedia.org/wiki/History_of_coffee).
2. Petracco tells us that the end products in coffee roasting are typically on the order of 10,000 Daltons (which is the same as saying “10,000 grams/mole”). Approximately how many atoms is that?
I’m not sure exactly how to do this and I’m trying to remember back to my high school chemistry class. I believe that we can use Avogadro’s number (6.02x10^23), which is equal to the number of atoms in 1 gram of a substance. So we could do 10,000 times Avogadro’s number to find out how many atoms are in that substance. It would then equal 6.02x10^27.
3. Activity to try at home, if possible: Place equal amounts of salt or sugar in two different glasses. To one, add cold water, and add hot water to the other. Which dissolves the substance the fastest? If the substance doesn’t dissolve immediately, what happens when you wait for a little while?
Salt dissolves better in hot water because the particle are moving around faster, because heat creates more energy in the particles.
4. Petracca states on p. 1166 that espresso is “often considered a ‘strong’ cup of coffee” and “fully deserves this attribute based on its sensory properties.” However, it generally contains a much smaller amount of caffeine than we might anticipate. Why is this (in terms of the chemistry of brewing)?
Espresso has less caffeine then a normal cup of coffee because of a couple reasons. A shot of espresso is usually very small and is brewed from a small amount of coffee beans. The pressure of the water pushed through the coffee grounds is high so the water has a very short contact with the coffee grounds. Caffeine dissolution is slow, so a lot of the caffeine stays in the grounds because the water was not in the coffee grounds for a long enough period of time.
5. In order for you to use olfaction to taste coffee, volatile molecules must make their way up inside your nose. Choose one or two molecules from the food-info page. Can you explain, in chemical terms, why these molecules are volatile, compared to water or a fatty acid (e.g., CH3(CH2)16COOH)?
I am not sure why certain molecules are volatile. I tried to look up some information, but I did not really understand it. I believe that Methional and vanillin are volatile because they are both light molecules that can easily evaporate.
6. One of the reasons for the success of coffee shops such as Starbucks is that they throw away beans that were roasted more than a week ago. Why are freshly roasted coffee beans better than months-old coffee (provide a chemical explanation)?
The longer that roasted coffee beans set out the more chemical reactions can occur to it so that the flavor is not as strong as freshly roasted coffee beans. The aroma of the coffee comes from roasting the coffee beans. After roasting, the coffee beans are at the perfect state for their flavor and smell. The longer the time after roasting, the more time chemical reactions can occur.
7. “Terpenes” is old nomenclature for molecules built from the 5 carbon isoprene unit: . Count the carbons in cafestol. If it is a “diterpene,” how many carbons are found in a terpene?
I counted 20 carbons in the cafestol molecule. Terpene molecules usually containg about 30 or more carbon molecules.
8. If you had the opportunity, would you want to try kopi luwak?
No, I don’t think I could ever drink coffee made from these beans. It sounds really gross!
9. Trace the history of tea from the far-east to the west. When was tea first discovered and how was it introduced to the west?
The legend of the discovery of tea believes that tea was discovered in 2737 BC by emperor Shen Nung who was interested in herbs. While drinking water, some leaves fell into his drink. Tea became popular under the Tang dynasty from 618-906 AD. Shortly after this tea was introduced to Japan. Later in the 16th century, tea was starting to appear in Europe. The Dutch traders were the first ones to ship back tea as a commercial import. The Dutch shipped back tea from Java, and it soon became a popular drink in Holland and it spread to other countries of Europe.
10. How was tea initially used during the Han Dynasty (206 BC – 220 AD)?
Tea was sent to the emperor’s court as a tribute to him.
11. Which western traders are credited for bringing tea to the west?
The Dutch were the first ones to bring tea back to Holland from Java. The Portuguese also brought tea back with them.
12. What was the Boston Tea Party about?
The British wanted to tax the colonist for the tea and the colonist were angry with them and believed that it was illegal to do this. The colonist would not let the ships leave nor would they let the ships unload. They then went aboard the ship one night and dumped all the tea in the water.
13. What addiction did the English create among the Chinese people due to their desperate dependency on Chinese tea?
Opium
14. Which chemical in tea has psycho active properties known to reduce mental and physical stress?
It is the polyphenols in the tea that help to reduce stress. It is also believed that the process of making the tea can be very relaxing for some people.
15. What other chemicals are found in tea and what are their therapeutical benefits?
Flavonoids – Antioxidant
Caffeine – reduces the sensation of being tired
Fluoride - Helps to prevent dental caries,
16. How is green tea produced?
The withered leaf is steamed and rolled before drying or firing. This prevents the veins in the leaf from breaking and stops any oxidizations of the leaf. Green tea has a very pale color and the wet leaf is often left whole.
17. How is black tea produced?
The leaves are set out to wither so that the moisture in the leaf evaporates in the warm air, which takes about 10 to 16 hours. The leaf is then broken by machine so that the natural juices are released and will oxidize. The leaves are then laid out to ferment or oxidize and it turned once and awhile. After oxidization passing through hot air chambers dries the leaves.
18. Read the Key Tasting Terms described in Tea Tasting Notes (page 1), and describe using the key tasting terms, how you prefer your cup of tea.
I like my tea to taste sweet. I also like to have a long length of time that I can taste my tea after I drink it. I like a balance of my tea.
19. Based on your moods, write down the types of teas you may wish to consume. (refer to the Tea Tasting Notes for tea and mood information)
- English Breakfast tea
- Assam
- Lady Grey’s
- Chai
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