One variable changed · simulated on the CoffeeScope V3 engine · updated 23 July 2026
Water temperature is the quietest of the big four dials — no change to grind, dose or ratio, just how hot the kettle is. We held everything else fixed and changed only the water temperature: a cool 85 °C against a near-boiling 96 °C — simulated in CoffeeScope.
Extraction is a chemical reaction, and reactions run faster when they are hotter. Cooler water pulls solubles out more slowly, so on a fixed recipe it tends to under-extract — a thinner, more sour cup — while hotter water extracts more of everything, gaining sweetness and body but risking bitterness if pushed too far. The practical question: on the same recipe, how much does 11 °C actually move the cup, and does cooler water leave real coffee on the table?
Both lanes are the simulator's stock V60 recipe (16 g, 1:16, 600 µm, spiral pour). The only difference is brew-water temperature: 85 °C vs 96 °C.
{
"brewer": "v60", "doseG": 16, "ratio": 16, "grindUm": 600,
"roastLevel": 0.4, "roastAgeDays": 7, "grindSpread": 0.45,
"bloomWaterX": 2, "bloomTimeS": 45, "pourRate": 4,
"pourHeight": 8, "pourPattern": "spiral", "bedLevel": 0,
"pourHeadroom": { "stopMm": 10, "resumeMm": 13 },
"resolution": "medium",
"waterTempC": 85 // Lane A — cool
"waterTempC": 96 // Lane B — near-boiling
}
Every number on this page is read from these two runs, taken to brew completion on the deterministic V3 engine.
Physics-based simulation, calibrated to move in the right direction — not a measurement of your specific coffee. How to read these numbers →
| Measure | 85 °C | 96 °C | Takeaway |
|---|---|---|---|
| Extraction yield (EY) | 18.3 % | 19.9 % | Cool water lands at the bottom edge of the ~18–22 % Gold Cup window; hot water sits squarely inside it. |
| Strength (TDS) | 1.27 % | 1.39 % | The hotter brew dissolves more into the same water — a fuller cup. |
| Drawdown time | 198 s | 198 s | Identical here: temperature changes reaction rate far more than it changes this bed's flow. |
| Cup volume | 230.0 ml | 229.8 ml | Same beverage volume — temperature shifts what dissolves, not how much water passes. |
| Cup temperature at finish | 63.2 °C | 70.5 °C | The cooler kettle also lands a cooler cup — worth remembering for drinking temperature. |
The taste axes are directional calibrations, not sensory-panel scores. A difference is flagged tasteable when it clears the model's own threshold of 0.045 (0–1 scale).
| Axis | 85 °C | 96 °C | Direction |
|---|---|---|---|
| Clarity | Very clean | Balanced | Small shift |
| Aroma | Muted | Aromatic | Small shift |
| Astringency | Soft | Slightly drying | Small shift |
| Body | Lighter | Fuller | Minimal shift |
| Bitterness | Clean | Slightly bitter | Minimal shift |
| Acidity | Bright | Bright | Minimal shift |
| Sweetness | Sweet | Sweet | Unchanged |
| Axis | 85 °C | 96 °C | Δ |
|---|---|---|---|
| Clarity | 0.76 | 0.69 | 0.07 |
| Aroma | 0.78 | 0.83 | 0.05 |
| Astringency | 0.00 | 0.05 | 0.05 |
| Body | 0.55 | 0.59 | 0.04 |
| Bitterness | 0.35 | 0.39 | 0.04 |
| Acidity | 0.57 | 0.55 | 0.02 |
| Sweetness | 0.47 | 0.46 | 0.01 |
Temperature is a quieter lever than its reputation: three of the seven axes shift tasteably, all in the direction extraction theory predicts. The cooler cup is cleaner; the hotter one is more aromatic (more volatiles extracted, though heat also destroys some) with a first hint of drying late-extraction compounds. Sweetness, acidity and bitterness barely move over these eleven degrees — on this recipe the choice is a clean-vs-aromatic style call, not a rescue.
Cumulative extraction yield, sampled during the brew:
| Time | 85 °C — EY | 96 °C — EY |
|---|---|---|
| 60 s | 7.1 % | 8.3 % |
| 120 s | 13.8 % | 15.4 % |
| Final | 18.3 % | 19.9 % |
The hot lane is ahead from the very first pour and never gives the lead back — the cooler brew is playing catch-up the whole way and still finishes short.
Each extraction channel in the model carries an Arrhenius temperature dependence: raise the water temperature and the rate constant climbs, so more of every soluble class comes out in the same contact time. Because the bed geometry and drawdown are unchanged, that extra rate translates directly into higher yield (18.3 % → 19.9 %) and TDS. The taste readback follows: aroma and body build as extraction moves deeper into the balanced window, while the cooler cup's higher clarity is the signature of a lighter extraction — clean and simple, with the aromatic, slightly drying side arriving only with heat. See the methodology for the Arrhenius extraction kinetics and heat-transport model.
Load this exact A/B in the live simulator and watch the temperature field drive the extraction field:
Run 85 °C vs 96 °C live →Get Early Access →
Related experiments: Medium vs coarse grind Light vs dark roast 1:14 vs 1:17 ratio