A brewhouse efficiency calculator measures how effectively your brewing system extracts fermentable sugars from grain during the mash and transfers them into the fermenter. Tracking mash efficiency and brewhouse efficiency across brew days helps you predict original gravity, dial in recipes, and identify where your process loses extract.
Grain Bill
Pre-Boil Readings
Volume in kettle before boil (gal)
Specific gravity reading before boil
Post-Boil Readings
Volume transferred to fermenter (gal)
Specific gravity reading after boil
Tips to Improve Efficiency
Finer grain crush
A finer crush exposes more starch to enzymes. Double-mill or adjust your mill gap to 0.035-0.040 inches.
Optimize water-to-grain ratio
A thinner mash (1.5-2.0 qt/lb) promotes better enzyme activity and starch conversion.
Fly sparge slowly
Fly sparging at a slow, steady rate rinses sugar more completely from the grain bed than batch sparging.
Check mash pH
Target a mash pH of 5.2-5.4 for optimal enzyme activity. Use brewing water salts or acid to adjust.
Mash longer if needed
A 60-minute mash is standard, but extending to 75-90 minutes can improve conversion of stubborn starches.
Mind grain bed depth
A deeper grain bed (3-4 inches minimum) acts as a natural filter and improves lautering. Avoid shallow beds.
Grain PPG Reference Table
PPG (points per pound per gallon) is the maximum extract potential of a grain. It represents the gravity points one pound of grain can yield when dissolved in one gallon of water at 100% efficiency.
| Grain Type | PPG | Notes |
|---|---|---|
| 2-Row Pale Malt | 37 | Standard base malt, most common |
| Pilsner Malt | 38 | Light base malt for lagers |
| Wheat Malt | 36 | Used in wheat beers, aids head retention |
| 6-Row Pale Malt | 35 | Higher enzyme content, lower extract |
| Vienna Malt | 35 | Lightly kilned, biscuity flavor |
| Munich Malt | 34 | Rich malty flavor, darker color |
| Crystal / Caramel Malt | 33 | Specialty malt, adds sweetness and color |
| Oat Malt | 33 | Adds body and silky mouthfeel |
| Roasted Barley | 32 | Dark color, coffee/chocolate notes |
How to Use the Brewhouse Efficiency Calculator
Knowing your brewhouse efficiency is essential for repeatable all-grain brewing. Without it, you are guessing at how much grain to use, and your original gravity will miss the target batch after batch. This free calculator takes your grain bill, pre-boil readings, and post-boil readings to compute mash efficiency, brewhouse efficiency, and lauter efficiency in seconds.
Step 1: Enter Your Grain Bill
Enter the total weight of grain used in your mash. Select the unit (pounds or kilograms) and choose the grain type from the dropdown to set the PPG (points per pound per gallon) value automatically. If your grain bill contains multiple grains, use a weighted average PPG or select the base malt since it typically makes up 80% or more of the grain bill. For mixed bills, you can also enter a custom PPG value.
Step 2: Record Pre-Boil Readings
After lautering and sparging, measure the total volume collected in your kettle before the boil starts. Take a gravity reading with a hydrometer or refractometer and enter the specific gravity (for example, 1.042). These pre-boil numbers are used to calculate mash efficiency, which tells you how much sugar the mash process extracted from the grain.
Step 3: Record Post-Boil Readings
After the boil, measure the volume that goes into the fermenter and the original gravity (OG). The post-boil volume is typically lower than pre-boil due to evaporation, and the gravity is higher because the wort has concentrated. These values are used to calculate brewhouse efficiency, which accounts for all losses from mash through fermenter transfer.
Step 4: Review Your Efficiency Numbers
The calculator displays three efficiency metrics: mash efficiency (typically 80-90%), brewhouse efficiency (typically 65-80%), and lauter efficiency (typically 85-95%). Each metric receives a grade from poor to excellent. The visual progress bars and detailed breakdown show exactly where your extract points went, helping you identify whether losses come from the mash, the lauter, or the boil.
Step 5: Use Results to Improve
Track your efficiency over several batches to find your system's baseline. Once you know your typical brewhouse efficiency, plug that number into recipe formulation software to hit your target gravity consistently. If mash efficiency is low, focus on grain crush and water chemistry. If lauter efficiency is low, work on your sparge technique and flow rate. The tips section below the results offers specific advice for each scenario. All calculations run in your browser, so your brew day data stays completely private.
FAQ
Is this brewhouse efficiency calculator really free?
Yes, the brewhouse efficiency calculator is completely free with no limits and no account required. All calculations run locally in your browser. Nothing is sent to any server or stored anywhere.
Is my brewing data safe and private?
Absolutely. Every calculation happens entirely in your browser using JavaScript. No brew day data is transmitted to any server, stored in any database, or shared with anyone.
What is the difference between mash efficiency and brewhouse efficiency?
Mash efficiency measures how much sugar you extracted during the mash and sparge, based on pre-boil volume and gravity. Brewhouse efficiency measures total extraction into the fermenter, accounting for boil-off losses, trub, and dead space. Brewhouse efficiency is always lower than mash efficiency.
What is a good brewhouse efficiency for homebrewing?
Most homebrewers achieve 65-75% brewhouse efficiency. Experienced brewers with well-tuned systems often reach 75-80%. Efficiency above 80% is excellent and typically requires fine-tuned crush, water chemistry, and sparge technique. BIAB systems typically see 60-70%.
How do I improve my mash efficiency?
The biggest factors are grain crush (finer crush extracts more), water-to-grain ratio (thinner mashes convert better), sparge technique (fly sparging is most efficient), and grain bed depth. Also ensure proper mash temperature and pH for complete starch conversion.
What is lauter efficiency and why does it matter?
Lauter efficiency measures how well you collect the sugary wort from the grain bed during the sparge. It is calculated as brewhouse efficiency divided by mash efficiency. Low lauter efficiency means you are leaving sugar behind in the grain, which can often be improved with slower sparging or more sparge water.
What PPG value should I use for my grain?
PPG (points per pound per gallon) varies by grain type. Use 37 for standard 2-row base malt, 36 for wheat malt, 35 for 6-row, 34 for Munich, and 33 for crystal and oat malts. The calculator includes a grain type selector with preset PPG values for common grains.
Why is my brewhouse efficiency different every batch?
Batch-to-batch variation is normal and can result from inconsistent grain crush, different grain bills, varying sparge techniques, temperature fluctuations, and equipment changes. Tracking efficiency over multiple batches helps you identify your system's baseline and spot issues early.