French Press (1:15 – Strong)
AeroPress (1:16 – Balanced)
Drip / Pour Over (1:17 – SCA Standard)
Chemex (1:18 – Light/Tea-like)
Espresso (1:2 – Traditional)
Custom Ratio
Brewing Recipe:
function updateCustomRatio() {
var method = document.getElementById("brewMethod").value;
var customDiv = document.getElementById("customRatioDiv");
if (method === "custom") {
customDiv.style.display = "block";
} else {
customDiv.style.display = "none";
}
}
function getRatio() {
var method = document.getElementById("brewMethod").value;
if (method === "custom") {
return parseFloat(document.getElementById("customRatio").value) || 0;
}
return parseFloat(method);
}
function calcByCoffee() {
var coffee = parseFloat(document.getElementById("coffeeWeight").value);
var ratio = getRatio();
var resDiv = document.getElementById("coffeeResult");
var resText = document.getElementById("resultText");
if (isNaN(coffee) || coffee <= 0 || isNaN(ratio) || ratio <= 0) {
alert("Please enter valid coffee weight and ensure ratio is set.");
return;
}
var waterNeeded = coffee * ratio;
resDiv.style.display = "block";
resText.innerHTML = "To use " + coffee + "g of coffee at a 1:" + ratio + " ratio, you need " + waterNeeded.toFixed(0) + "ml of water.";
}
function calcByWater() {
var water = parseFloat(document.getElementById("waterVolume").value);
var ratio = getRatio();
var resDiv = document.getElementById("coffeeResult");
var resText = document.getElementById("resultText");
if (isNaN(water) || water <= 0 || isNaN(ratio) || ratio <= 0) {
alert("Please enter valid water volume and ensure ratio is set.");
return;
}
var coffeeNeeded = water / ratio;
resDiv.style.display = "block";
resText.innerHTML = "To make " + water + "ml of coffee at a 1:" + ratio + " ratio, use " + coffeeNeeded.toFixed(1) + "g of coffee grounds.";
}
The Science of the Golden Ratio in Coffee
Coffee brewing is essentially a game of extraction. To get the best flavor out of your beans, you must balance the amount of coffee grounds with the amount of water used. This is known as the Coffee-to-Water Ratio.
Why is the Ratio Important?
If you use too much water, the coffee becomes "over-extracted," leading to a bitter, thin, and hollow taste. If you use too little water, the coffee is "under-extracted," resulting in a sour, salty, or overly concentrated brew. The Specialty Coffee Association (SCA) suggests a "Golden Ratio" of 1:18, but most home enthusiasts find a range between 1:15 and 1:17 to be the sweet spot.
Common Coffee Ratios by Brew Method
Method
Ratio
Resulting Profile
Espresso
1:2
Intense, syrupy, concentrated
French Press
1:15
Heavy body, rich, bold
Pour Over / Drip
1:16 – 1:17
Clean, balanced, highlights origin notes
Cold Brew
1:8 (Concentrate)
Smooth, low acidity, very strong
Realistic Calculation Example
Let's say you are making a standard morning mug of coffee (roughly 350ml or 12oz). If you are using a standard 1:17 ratio for a drip machine:
Total Water: 350ml
Calculation: 350 / 17 = 20.5
Result: Use 20.5 grams of coffee grounds.
Tips for the Perfect Brew
Use a Scale: Volumetric measurements (scoops and cups) are notoriously inaccurate because dark roasts are less dense than light roasts. Always measure by weight in grams.
Water Temperature: Aim for 195°F to 205°F (90°C – 96°C).
Grind Size: Match your grind to your method. Coarse for French Press, medium for Drip, and fine for Espresso.
Freshness: Grind your beans immediately before brewing to preserve the volatile aromatic oils.