Questions: Tea and Coffee Preparation

Question 1

You brew a cup of green tea using water that just came off a full boil (212°F/100°C). It tastes sharp and unpleasantly bitter. What most likely explains this?

• A. The tea leaves were too old and stale
• B. The boiling water over-extracted bitter compounds that green tea's delicate chemistry releases at high temperatures
• C. You used too little tea relative to the water volume
• D. You didn't steep it long enough for the flavor to fully develop

Answer: (B)

Green tea is typically brewed at 160–175°F specifically because its delicate compounds extract — and its bitter tannins over-extract — at lower temperatures than black tea. Boiling water doesn't bring out more flavor; it brings out the wrong flavor. This is a case where the common intuition 'hotter is better' directly produces a worse result.

Question 2

Your morning coffee tastes sour and thin, lacking richness. Which adjustment most directly addresses an under-extraction problem?

• A. Use less coffee per cup of water
• B. Use cooler water to slow the extraction
• C. Increase the water temperature or extend contact time
• D. Switch to a coarser grind

Answer: (C)

Sourness and thinness indicate under-extraction — desirable aromatic compounds haven't fully dissolved into the water. The fix is to increase extraction: hotter water or longer contact time (or a finer grind, which increases surface area and speeds extraction). Using less coffee or cooler water would worsen the problem. A coarser grind would also under-extract further.

Question 3

Black tea and green tea are both made from the same plant (Camellia sinensis), but they require different brewing water temperatures.

• T. True
• F. False

Answer: True

True. Processing differences — green tea is minimally oxidized while black tea is fully oxidized — change the chemical composition of the leaf and therefore the extraction behavior. Green tea's delicate, volatile compounds are destroyed by high heat, and its bitterness is easily over-extracted; black tea's robust flavors require the higher temperature to fully dissolve. Same plant, very different optimal brewing temperatures.

Question 4

Steeping tea for twice the recommended time is a reliable way to get a stronger, more flavorful cup.

• T. True
• F. False

Answer: False

False. Desirable flavor compounds extract quickly in the first few minutes; the astringent tannins and polyphenols that cause bitterness extract more slowly and continue accumulating with extended steeping. Doubling the steep time doesn't double the flavor — it produces a bitter, tannic cup. The recommended steep time represents the optimal extraction window, after which the beverage degrades rather than improves.

Question 5

Why does grind size affect extraction in coffee, and how does it relate to contact time?

Model answer: Finer grinds have more surface area, so water contacts more of the coffee simultaneously and extracts faster. This means a fine grind needs shorter contact time or lower temperature to avoid over-extraction. A coarse grind has less surface area, extracts more slowly, and needs longer contact time. Grind size is effectively a way to control the extraction rate — which is why espresso (very fine, 25–30 seconds) and French press (coarse, 4 minutes) require completely different contact times to achieve balanced extraction.

Surface area and contact time are inversely related in well-designed brewing: as surface area increases, you need to compensate by decreasing contact time. Understanding this relationship lets you diagnose and fix extraction problems by adjusting any of the three variables — temperature, time, or grind — rather than needing to memorize separate rules for each brewing method.