Calculator Inputs
Example Data Table
| Batch | OG | FG | Hop Weight | Alpha Acid | Boil Time | Expected Focus |
|---|---|---|---|---|---|---|
| Pale Ale Trial | 1.050 | 1.012 | 50 g | 5.5% | 60 min | Balanced strength and bitterness |
| Session Batch | 1.040 | 1.010 | 35 g | 4.8% | 45 min | Lower alcohol planning |
| Dark Malt Test | 1.060 | 1.016 | 40 g | 6.0% | 60 min | Color and body review |
Formula Used
Alcohol by volume: ABV = (OG - FG) × 131.25.
Apparent attenuation: Attenuation = ((OG - FG) / (OG - 1)) × 100.
Estimated gravity: Gravity points = PPG × grain pounds × efficiency / batch gallons.
Tinseth bitterness: IBU = hop grams × alpha fraction × utilization × 1000 / liters.
Color: MCU = Lovibond × grain pounds / gallons. SRM = 1.4922 × MCU^0.6859.
Strike water: Strike temperature adjusts target mash temperature by grain temperature and mash thickness.
Priming sugar: Dextrose grams = added CO₂ volumes × liters × 4.0.
How to Use This Calculator
- Enter the batch volume, original gravity, and final gravity.
- Add grain weight, potential, and efficiency for predicted gravity.
- Enter hop weight, alpha acid, and boil time for bitterness.
- Add malt color data for a color estimate.
- Enter mash and grain temperature for strike water planning.
- Enter beer temperature and target CO₂ for priming sugar.
- Press the calculate button to show results above the form.
- Download the CSV or PDF file for recipe records.
Brewing Calculation Guide
Brewing rewards careful measurement. A small gravity change can alter strength. Hop timing changes bitterness fast. Color depends on grain weight, shade, and volume. Carbonation needs temperature knowledge. This handbook style calculator joins those checks in one page. It helps home brewers, pilot brewers, and recipe planners compare targets before brew day. It does not replace records. It organizes them. Use readings from a calibrated hydrometer or refractometer. Use stable volume measurements. Then compare the results with taste, fermentation behavior, and yield.
Why These Numbers Matter
Original gravity shows dissolved sugar before fermentation. Final gravity shows what remains. Their difference estimates alcohol strength and apparent attenuation. Estimated gravity from grain weight helps you test mash efficiency. Bitterness uses hop weight, alpha acid, boil time, volume, and gravity. Color uses malt color units and the Morey curve. Strike temperature helps hit mash rests. Priming sugar estimates bottle conditioning needs from beer temperature and target carbonation.
Better Brew Planning
Use the calculator during recipe design. Start with a normal batch volume. Enter your expected original and final gravity. Add grain data if you want a predicted gravity. Add hop data for bitterness. Enter malt color to estimate visual depth. Adjust one input at a time. This shows which ingredient drives the result. Save each result as CSV. Download a PDF for your brewing folder. Repeat the same process after brew day. Actual readings create better future recipes.
Practical Accuracy Tips
Sanitize sampling tools. Cool wort before gravity readings. Correct hydrometer readings for temperature when needed. Weigh hops and grain carefully. Record boil length and final volume. Keep carbonation targets realistic for the beer style. Use the strike water output as a starting point. Real mash systems lose heat differently. Kettle shape, grain crush, yeast health, and fermentation temperature can affect results. Treat every number as a guide. Brewing improves when calculations and tasting notes work together.
Recording Results
A clear log makes the calculator more useful. Note recipe date, yeast strain, mash length, water salts, and room temperature. Keep original notes beside exported tables. When a batch tastes balanced, reuse its numbers. When a batch misses, compare inputs first. This habit turns simple arithmetic into dependable brewing decisions later.
FAQs
What does original gravity mean?
Original gravity measures dissolved sugars before fermentation. Higher values usually mean more fermentable material. It helps estimate strength, balance, and yeast workload.
What does final gravity mean?
Final gravity measures remaining extract after fermentation. It helps estimate dryness, body, apparent attenuation, and alcohol strength when compared with original gravity.
Is the alcohol result exact?
No. It is an estimate based on common brewing math. Accurate readings, temperature correction, and calibrated tools improve the result.
Why does bitterness change with gravity?
Higher gravity wort can reduce hop utilization. The Tinseth method includes gravity, boil time, hop weight, alpha acid, and volume.
What is SRM?
SRM estimates beer color. This calculator uses malt color units and the Morey equation to provide a practical color estimate.
Can I use kilograms and liters?
Yes. The form accepts metric entries. The calculator converts values internally when formulas require pounds, gallons, or quarts.
Why is strike water temperature only a guide?
Mash tuns, grain crush, room temperature, and heat loss vary. Use the result as a starting point and adjust with your own records.
Can I save my brewing results?
Yes. After calculation, use the CSV button for spreadsheet records. Use the PDF button for a simple printable report.