Does less water make better coffee? A pour-over ratio experiment

The myth of the golden ratio

If you've spent any time reading about pour-over coffee, you've encountered the 1:16 ratio — one gram of coffee for every 16 grams of water. It shows up in every beginner's guide, and it's a reasonable place to start. But calling it "golden" implies it's the best, and that's a much harder claim to defend.

Ratio is one of several variables in extraction, alongside grind size, water temperature, and contact time — and all of them interact. To understand what ratio actually does to a cup, you need to isolate it as cleanly as possible and taste the results. That's exactly what this experiment sets out to do.

 

How the experiment was set up

Five brews, same coffee, same grind size, same water temperature, same recipe structure. The only variable was how much water hit the 15 grams of coffee in each cup: 180 ml, 210 ml, 240 ml, 270 ml, and 300 ml — giving ratios of 1:12, 1:14, 1:16, 1:18, and 1:20 respectively.

Keeping the dose fixed at 15 grams mattered. The temptation with ratio experiments is to adjust the dose instead, keeping water constant, but that introduces bed depth as an additional variable. A deeper bed of grounds creates a different flow rate and extraction pattern. By changing only the final water volume, the bed depth stayed consistent across all five brews.

Each brew used a 45-gram bloom, then a single pour to the target volume. Contact time varied slightly — an unavoidable consequence of using more or less water — but that trade-off is inherent to isolating ratio and was accepted as part of the test.

 

What TDS tells you — and what it doesn't

Before tasting, each brew was measured for TDS (total dissolved solids) and extraction yield. TDS is simply the percentage of the liquid that isn't water. A reading of 1.3 means 1.3% of your brewed coffee is dissolved material — the rest is water. Extraction yield tells you what percentage of the coffee's dry mass made it into the cup.

The results were predictable in direction but striking in magnitude:

• 1:12 — TDS 1.73 / extraction yield 16.86%
• 1:14 — TDS 1.51 / extraction yield 17.8%
• 1:16 — TDS 1.36 / extraction yield 18.9%
• 1:18 — TDS 1.22 / extraction yield 19.4%
• 1:20 — TDS 1.09 / extraction yield 19.74%

 

The tighter ratio produced a far more concentrated brew but extracted less from the coffee. The looser ratio extracted more yet tasted much weaker. That inverse relationship — more water means higher extraction yield even though the cup seems thinner — is one of the least intuitive things about coffee brewing. More solvent refreshes the concentration gradient between the liquid and the grounds, pulling more compounds out even as it dilutes what's already there.

It's also worth noting what TDS numbers can't tell you: whether the cup is actually good. A 20% extraction can taste bright and floral or harsh and bitter depending on which compounds were extracted. The numbers are a map, not the territory.

 

Equalizing concentration — and what that reveals

Tasting five cups at wildly different concentrations makes fair comparison difficult. The 1:12 brew is thick and syrupy; the 1:20 is thin and tea-like. Your palate responds as much to intensity as to flavor. To get a cleaner read on extraction quality, the brews were diluted to a common TDS of 1.3 using a straightforward equation: C1 × V1 = C2 × V2. Plug in the measured TDS, your target TDS, and your current volume, and you get exactly how much water to add.

Why 1.3? It sits comfortably in the range — 1.15 to 1.35 — that research from the 1950s identified as where most drinkers find their preference, a benchmark that has held up surprisingly well. At that concentration, there's enough body to support the coffee's acidity and sweetness without the brew feeling either punchy or flat.

Once equalized, the cups told a more nuanced story. The highest-extraction brew (1:20) was bright to the point of sharpness — acidity without quite enough balance to hold it together. The lowest-extraction brew (1:12) was pleasant but restrained, its positive qualities somewhat muted. The sweet spot landed around the 1:16 to 1:18 range — not because the "golden ratio" is universally correct, but because at this particular grind size and water temperature, those ratios happened to pull the right balance of compounds. A different coffee, a coarser grind, or cooler water could shift that sweet spot entirely.

 

When it's better to brew tight and dilute

One of the more counterintuitive takeaways: brewing at a tighter ratio and diluting afterward can produce a better cup than brewing at your target ratio directly. When you extract at 1:12 and then add water to reach 1.3 TDS, you're capturing the early-extraction compounds — fruit, sweetness, florals — at high concentration, then lowering the intensity with clean water. Brewing at 1:20 to chase those same TDS numbers isn't really an equivalent swap, because the looser ratio has also pulled more of the bitter, late-extraction compounds into the cup.

This is where a refractometer earns its place, even a budget one. You don't need a lab-grade instrument. As long as your device gives consistent readings, you can use C1V1 = C2V2 to dilute any brew to your preferred strength. If your refractometer reads 1.5 where a calibrated unit would read 1.27, that's fine — your preference is a consistent "1.5 on my device," and the math works the same. The point isn't precision for its own sake; it's repeatability.

 

Frequently Asked Questions

What is the best coffee-to-water ratio for pour-over?

There is no universally best ratio. The commonly recommended 1:16 is a solid starting point, but your ideal ratio depends on your grind size, water temperature, and personal taste. Experimenting between 1:14 and 1:18 and adjusting from there is more useful than treating any single number as a rule.

 

What does TDS mean in coffee?

TDS stands for total dissolved solids — the percentage of your brewed coffee that isn't water. A TDS of 1.3 means 1.3% of the liquid is dissolved coffee compounds. It measures concentration, not quality. Most drinkers find their preference somewhere between 1.15 and 1.35 TDS.

 

Does using less water make coffee taste better?

It makes coffee more concentrated, which some people prefer. But less water also means a lower extraction yield — fewer compounds are pulled from the grounds. Whether that tastes "better" depends on the coffee and your palate. Brewing tight and diluting afterward is often the best of both worlds: high-quality early-extraction compounds at a drinkable concentration.

 

How do I dilute coffee to the right strength?

Use the dilution equation C1 × V1 = C2 × V2. Measure your current TDS (C1) and volume (V1), set your target TDS (C2), and solve for the new volume (V2). The difference between V2 and V1 is how much water to add. A budget refractometer is enough to make this work consistently — absolute accuracy matters less than consistency.

 

How does water ratio affect extraction yield?

More water refreshes the concentration gradient between the liquid and the coffee grounds, which drives more extraction. A 1:20 ratio will produce a higher extraction yield than a 1:12 ratio even though the resulting cup tastes weaker. This is why TDS and extraction yield move in opposite directions as you add more water.

 

What this experiment actually teaches you

Ratio matters — and it matters more than most people expect. Shifting from 1:12 to 1:20 with the same coffee and grind produces measurably different extractions and dramatically different concentrations. The "golden ratio" landed somewhere in the middle of the preference range here, but that was partly circumstantial: it happened to suit the specific coffee, grind, and temperature in this test.

The more durable lesson is that finding your preferred TDS is more important than hitting any particular ratio. Once you know what concentration you enjoy, you can brew anywhere and dilute to get there — or use ratio deliberately as a lever to push extraction in one direction or another.

Brew a few cups at different ratios. Taste them undiluted, then equalize the concentration and taste again. What you learn about your own preferences will tell you far more than any number on a bag.