How Brewing Temperature Affects Coffee Taste

Main Ideas

Brewing temperature is often misunderstood. The old advice to let boiled water cool so it would not “burn” coffee is challenged: coffee is roasted at much higher temperatures. Hotter water can increase extraction, but the more important question is how it affects the cup’s taste.

The presenter suggests that higher temperatures may bring out more roastiness and bitterness, even in very light-roasted coffee. Cooler water can reduce bitterness, but water that is too cool may produce a dull cup with little structure.

Temperature is only one way to affect extraction. If a coffee needs more extraction, the presenter suggests adjusting grind size, agitation, or brew structure rather than relying on hotter water alone.

The results are an exploratory example, not a general rule. The test used one coffee, one setup, and one tasting. Personal preference matters, and bitterness is not inherently undesirable.

Experiment and Method

The presenter brewed the same lightly roasted coffee five times, changing only the water temperature:

• Temperatures: 96°C, 93°C, 90°C, 87°C, and 84°C
• Recipe: 15 g of coffee to 250 g of water
• Brewer and technique: Plastic V60, same filter and grind, and a three-pour recipe

The V60 was rinsed between brews to return it to roughly the same starting temperature. Before the blind tasting, the coffee samples were brought to the same temperature so the taster could not identify them by warmth. However, stirring the samples to equalize their temperatures made the experiment imperfect.

Extraction measurements were kept from the taster until after the tasting to avoid influencing perceptions. The presenter also cautions that variable-temperature kettles may not deliver their displayed temperature precisely. Small differences, such as 1°C, may be within a kettle’s margin of error, so larger temperature intervals are more useful for home comparisons.

Tasting Results

The presenter’s favorites were 90°C and 93°C, with 87°C also enjoyable.

• 96°C: More complex and structured, but with a noticeable roasty, caramelized bitterness that the presenter did not prefer.
• 87°C: A juicier impression of acidity, but less sweetness and balance than the preferred cups.
• 84°C: Comparatively dull and less aromatic, with little bitterness but insufficient structure and excitement.

The presenter correctly identified the samples’ temperature order during the blind tasting, but emphasizes that this was a single tasting. The same preferences may not hold for other coffees or brewers.

Measurements and Interpretation

Brew times, from hottest to coolest, were 2:31, 2:20, 2:10, 2:20, and 2:27. They did not steadily increase as the water cooled; instead, they dipped in the middle and rose again at the cooler temperatures. The presenter treats this unexpected pattern cautiously, noting that it could reflect small variations or other factors.

The reported extraction yield fell by about 1.5 percentage points from the hottest brew to the coolest. Adjacent differences were approximately 0.7, 0.15, 0.4, and 0.2 percentage points.

TDS differences were described as smaller than the extraction-yield differences, though the subtitle figures were inconsistent. The presenter’s takeaway is that measured extraction changed with temperature, but those numbers alone do not determine which cup tastes best.

The broader lesson is to test variables independently and judge by taste rather than assuming that higher extraction—or a particular temperature—is automatically better.

Speakers and Sources Featured

• Lance Hedrick: Presenter, brewer, and taster.
• Hugo: Briefly assists by rearranging the cups for the blind tasting.
• An unnamed friend who works in chemistry: Referenced in connection with sensory experiments suggesting that a temperature difference of about 3°C may be needed to detect a difference.
• Sensory experiments on espresso: Mentioned by the presenter, but no specific study or researcher is identified.