.beer-recipe-calculator {
font-family: Arial, sans-serif;
max-width: 600px;
margin: 20px auto;
padding: 20px;
border: 1px solid #ccc;
border-radius: 8px;
box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}
.beer-recipe-calculator h2, .beer-recipe-calculator h3 {
text-align: center;
margin-bottom: 20px;
color: #333;
}
.input-group {
margin-bottom: 15px;
display: flex;
align-items: center;
justify-content: space-between;
}
.input-group label {
flex-basis: 50%;
margin-right: 10px;
font-weight: bold;
color: #555;
}
.input-group input[type="number"] {
flex-basis: 40%;
padding: 8px;
border: 1px solid #ddd;
border-radius: 4px;
box-sizing: border-box;
}
button {
display: block;
width: 100%;
padding: 10px;
background-color: #4CAF50;
color: white;
border: none;
border-radius: 4px;
font-size: 16px;
cursor: pointer;
transition: background-color 0.3s ease;
}
button:hover {
background-color: #45a049;
}
#result {
margin-top: 20px;
padding: 15px;
background-color: #f9f9f9;
border: 1px dashed #eee;
border-radius: 4px;
text-align: center;
font-size: 1.1em;
color: #333;
}
#result p {
margin-bottom: 10px;
}
function calculateBeerRecipe() {
var batchSize = parseFloat(document.getElementById("batchSize").value);
var grainWeight = parseFloat(document.getElementById("grainWeight").value);
var grainSRM = parseFloat(document.getElementById("grainSRM").value);
var boilTime = parseFloat(document.getElementById("boilTime").value);
var mashTemp = parseFloat(document.getElementById("mashTemp").value);
var efficiency = parseFloat(document.getElementById("efficiency").value) / 100; // Convert to decimal
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
if (isNaN(batchSize) || isNaN(grainWeight) || isNaN(grainSRM) || isNaN(boilTime) || isNaN(mashTemp) || isNaN(efficiency)) {
resultDiv.innerHTML = "Please enter valid numbers for all fields.";
return;
}
// — Beer Recipe Calculations —
// 1. Estimated Original Gravity (OG) – Using a simplified formula (Potential points per kg/L)
// This is a very rough estimate, actual OG depends on malt types and conversion.
// A common value for Pilsner malt is around 300-310 gravity points per kg per liter (adjusted for efficiency).
// For simplicity, let's assume an average malt potential.
var maltPotentialPPG = 300; // Approximate potential points for 1 kg of grain in 1 L of water
var estimatedPoints = grainWeight * maltPotentialPPG * efficiency;
var estimatedOG = 1.000 + (estimatedPoints / batchSize); // OG = 1 + (Points / Volume)
// 2. Estimated Color (SRC – Standard Reference Color) – Based on Daniels' Formula (simplified)
// This formula estimates color based on grain weight, SRM of grain, and batch size.
// A more complex formula would account for hop utilization for bitterness.
var estimatedSRM = (grainWeight * grainSRM * 0.5) / batchSize; // Very rough estimate
// Adjust SRM for boil time – longer boils can lead to caramelization and darker color.
// This is a heuristic and highly variable.
if (boilTime > 60) {
estimatedSRM *= (1 + (boilTime – 60) / 120); // Minor increase for longer boils
}
// 3. Estimated IBU (International Bittering Units) – Placeholder – Requires hop addition data
// Calculating IBU requires specific hop varieties, amounts, alpha acid, and boil time.
// This is beyond a simple calculator without more inputs.
var estimatedIBU = "N/A (requires hop details)";
// — Display Results —
var outputHTML = "Estimated Original Gravity (OG):
" + estimatedOG.toFixed(3) + "";
outputHTML += "Estimated Color (SRM):
" + estimatedSRM.toFixed(1) + "";
outputHTML += "Estimated IBU:
" + estimatedIBU + "";
outputHTML += "Mash Temperature will influence enzyme activity and resulting fermentable sugars.";
resultDiv.innerHTML = outputHTML;
}
Understanding Your Beer Recipe Estimates
This beer recipe calculator provides estimations for key beer parameters based on your input. It's a helpful tool for planning your brew day, but remember that actual results can vary based on numerous factors.
Batch Size (Liters)
This is the final volume of beer you expect to have after brewing, fermentation, and packaging. It's the target volume for your recipe.
Total Grain Weight (kg)
This represents the total mass of all grains (malted barley, wheat, etc.) you intend to use in your mash. The type and amount of grain are primary drivers of the beer's flavor, body, and alcohol content.
Average Grain SRM
SRM (Standard Reference Method) is a unit of measurement for the color of beer. The average SRM of your grains gives an initial indication of how dark your beer will be. Different malt types contribute different colors and flavors.
Boil Time (Minutes)
The boil is a critical step in brewing where hops are added for bitterness, flavor, and aroma, and to sterilize the wort. Longer boil times can lead to caramelization of sugars, potentially darkening the beer, and can also affect hop utilization.
Mash Temperature (°C)
During the mash, enzymes in the malt convert starches into fermentable and non-fermentable sugars. The mash temperature is crucial: lower temperatures tend to favor the production of more fermentable sugars (leading to a drier, higher-alcohol beer), while higher temperatures favor non-fermentable sugars (leading to a fuller-bodied beer).
Mash Efficiency (%)
Mash efficiency refers to how effectively your brewing system extracts fermentable sugars from the grain during the mash. A higher efficiency means more sugar is extracted, resulting in a higher potential alcohol content for the same amount of grain.
What the Estimates Mean:
- Estimated Original Gravity (OG): This number, usually expressed as a decimal (e.g., 1.050), indicates the density of your wort before fermentation. Higher OG generally means higher potential alcohol content. This calculator provides a rough estimate based on your grain bill and mash efficiency.
- Estimated Color (SRM): This estimates the final color of your beer. The calculation is a simplified approximation. The actual color can be influenced by boil duration, Maillard reactions (caramelization), and adjuncts.
- Estimated IBU (International Bittering Units): Calculating IBU accurately requires precise details about the hops used (variety, alpha acid content, amount) and when they are added during the boil. Since these details are not inputs here, the calculator states "N/A" and prompts for more specific hop information for an accurate IBU calculation.
Brewing is both a science and an art. Use these estimates as a guide, but be prepared to adjust and learn from each batch!