Chapter 34 — Quiz
A mix of recall, application, and "explain why" questions. Answer key with explanations at the bottom. Total: 18 questions (14 multiple choice, 4 short answer).
Multiple Choice
1. Cacao fermentation typically lasts how long?
A) 6–12 hours B) 1–2 days C) 5–7 days D) 2–3 weeks
2. During cacao fermentation, the FIRST microbial group to dominate is:
A) Acetic acid bacteria B) Lactic acid bacteria C) Yeasts D) Molds
3. During cacao fermentation, the LAST microbial group to dominate (Phase 3) is:
A) Yeasts B) Lactic acid bacteria C) Acetic acid bacteria D) Methanogens
4. Coffee was originally domesticated by Indigenous peoples of:
A) Yemen B) Indonesia C) Brazil D) Ethiopia
5. Which coffee processing method involves drying whole cherries (fruit and all) on patios for 2–4 weeks?
A) Washed B) Natural C) Honey D) Anaerobic
6. Which coffee processing method typically produces the cleanest, brightest, most acidic cup?
A) Washed B) Natural C) Honey D) Anaerobic
7. The transformation that distinguishes green tea from black tea is:
A) Microbial fermentation by Aspergillus niger B) Enzymatic oxidation by polyphenol oxidase C) Maillard reaction during processing D) Lactic acid fermentation
8. Pu-erh tea is produced from the leaves of:
A) Camellia japonica B) Camellia sinensis C) Theobroma cacao D) Coffea arabica
9. Shou pu-erh ("ripe" pu-erh) was developed in 1973. What does it simulate?
A) The taste of green tea B) The long-term aging of sheng pu-erh in about 45 days C) The flavor of black tea D) Coffee fermentation
10. The dominant microbe in shou pu-erh pile fermentation is:
A) Saccharomyces cerevisiae B) Lactobacillus plantarum C) Aspergillus niger D) Penicillium camemberti
11. Coffee was first commercialized as a beverage in:
A) Ethiopia B) Yemen C) Turkey D) Italy
12. Anaerobic coffee fermentation involves:
A) Removing all microbes from the bean B) Sealing the cherry or bean in oxygen-restricted vessels for controlled fermentation C) Drying the bean completely before fermentation D) Adding alcohol to the fermentation
13. The "fermentation" of black tea is:
A) Microbial fermentation by yeasts and bacteria B) Enzymatic oxidation, mostly by polyphenol oxidase C) A combination of both D) Neither — it is purely thermal transformation
14. Approximately what fraction of the world's cocoa is grown in West Africa?
A) 20% B) 35% C) 60–70% D) 90%
Short Answer
15. Briefly explain the role of acetic acid bacteria in cacao fermentation. Why is the heat they generate important for the bean's internal transformation?
16. The chapter argues that "all coffee is, to some extent, a fermented food." Defend this statement.
17. What is the difference between sheng and shou pu-erh? How do their flavor profiles and price points typically compare?
18. The chapter names specific Indigenous peoples — Galla/Oromo, Bulang/Dai, Olmec/Maya/Mexica — as the originators of these foods. Why is this naming important rather than the generic "discovered in Ethiopia/China/Mesoamerica"?
Answer Key
1. C) 5–7 days. Cacao fermentation runs 5–7 days under traditional heap or box conditions, through three microbial phases.
2. C) Yeasts. Saccharomyces, Hanseniaspora, Pichia species dominate the first 24 hours, fermenting pulp sugars to ethanol.
3. C) Acetic acid bacteria. Acetobacter and Gluconobacter species dominate days 4–7, oxidizing ethanol from Phase 1 into acetic acid. This phase is highly exothermic, producing the heat that drives the bean's internal transformation.
4. D) Ethiopia. Coffee was domesticated by Indigenous peoples (notably the Galla/Oromo) of the Ethiopian highlands. Yemen was where coffee was first commercialized as a beverage in the medieval period.
5. B) Natural. Natural processing leaves the entire fruit on the bean during sun-drying for 2–4 weeks. Washed, honey, and anaerobic methods all involve some pre-processing of the fruit before drying.
6. A) Washed. Washed coffees typically taste cleanest and brightest because the mucilage is removed before drying, so the bean dries without prolonged contact with fermenting fruit pulp.
7. B) Enzymatic oxidation by polyphenol oxidase. Despite the traditional industry term "fermentation," the green-to-black tea transformation is enzymatic oxidation. Microbes are not involved.
8. B) Camellia sinensis. Both pu-erh and all other true teas come from this species (Camellia sinensis), specifically the Chinese variety (var. sinensis) and the Assamese variety (var. assamica).
9. B) The long-term aging of sheng pu-erh in about 45 days. The wò duī ("wet pile") technique developed at the Kunming Tea Factory uses controlled microbial fermentation to simulate, in 45–60 days, the slow microbial transformation that aged sheng undergoes over years to decades.
10. C) Aspergillus niger. The black-spored mold A. niger (and the closely related A. luchuensis) dominates pu-erh pile fermentation, producing the theabrownins and gallic acid that characterize shou pu-erh.
11. B) Yemen. While coffee was domesticated in Ethiopia, it was first commercialized as a beverage in Yemen in the 15th century, and from there spread through the Arab world to Europe.
12. B) Sealing the cherry or bean in oxygen-restricted vessels for controlled fermentation. Often combined with intentional bacterial dominance, controlled temperature, and sometimes added microbial cultures. A specialty-coffee innovation since around 2010.
13. B) Enzymatic oxidation, mostly by polyphenol oxidase. The same PPO that browns a cut apple oxidizes tea catechins to theaflavins and thearubigins, producing the dark color and characteristic flavors of black tea.
14. C) 60–70%. Côte d'Ivoire alone produces about 40% of world cocoa; Ghana adds another ~20%. Together with Cameroon and Nigeria, West Africa produces 60–70% of the world's cacao.
15. Acetic acid bacteria (Acetobacter, Gluconobacter) oxidize ethanol (produced by yeasts in Phase 1) into acetic acid in Phase 3 of cacao fermentation. This reaction is highly exothermic — heap temperatures rise to 45–50°C. The combination of heat and acid penetrates the bean: it kills the seed embryo, breaks down internal cell membranes, activates bean proteases that hydrolyze storage proteins into free amino acids, and oxidizes catechins to less astringent compounds. Without this acetic-acid-and-heat phase, the bean does not develop the flavor precursors that roasting will later combine into chocolate flavor.
16. Even in washed processing — the cleanest of the methods — the depulped beans spend 12–48 hours in tanks of water where microbial activity (yeasts, lactic acid bacteria, acetic acid bacteria) digests remaining mucilage. Natural processing involves several weeks of microbial activity around the bean during fruit-on drying. Honey processing retains mucilage that ferments during drying. Anaerobic processing involves controlled microbial fermentation in sealed tanks. All four standard methods involve microbial steps. The differences between them are differences in how the fermentation was managed, not whether fermentation happened. Coffee is a fermented food in every commercial form.
17. Sheng pu-erh ("raw" pu-erh) is essentially a pressed green tea that ages naturally over years to decades through slow microbial action. Young sheng tastes vegetal and bitter; aged sheng (10+ years) tastes deep, woody, mellow, with a sweet aftertaste. Shou pu-erh ("ripe") is a 1973 innovation that uses a 45-day pile-fermentation (wò duī) to simulate aged sheng's character; it tastes earthy, smooth, immediately drinkable. Price: shou is affordable (20–50 USD per cake); aged sheng from named mountains can cost 500+ USD per cake; very old sheng can reach tens of thousands.
18. Generic geographic attributions ("discovered in Ethiopia/China/Mesoamerica") obscure the specific human work of specific peoples over many generations. Coffee did not just "appear" in Ethiopia — it was domesticated and developed by the Galla/Oromo and other peoples of southwestern Ethiopia in landscapes their descendants still cultivate. Tea did not just "appear" in China — it was domesticated and refined by the Bulang, Dai, Yi, Hani, Wa, Lahu, and Han Chinese peoples of Yunnan and Sichuan. Cacao did not just "appear" in Mesoamerica — it was developed across millennia by specific civilizations: the Olmec, Maya, Mexica/Aztec, and others. Naming the actual originators credits real human labor and knowledge, prevents the "discovery" narrative that erases pre-contact achievements, and supports current efforts by Indigenous communities to reclaim and benefit from their food traditions.