Enter Gravity Readings
Example Data Table
| Original Gravity | Final Gravity | Standard ABV | Likely Style Range |
|---|---|---|---|
| 1.040 | 1.010 | 3.94% | Light ale or session beer |
| 1.060 | 1.012 | 6.30% | Strong ale or cider |
| 1.080 | 1.018 | 8.14% | Imperial ale or strong wine |
| 1.100 | 1.025 | 9.84% | High gravity fermentation |
Formula Used
Standard ABV: ABV = (Original Gravity - Final Gravity) × 131.25
Alternate ABV: ABV = (Original Gravity - Final Gravity) × 133.62
Advanced ABV: ABV = (76.08 × (OG - FG) / (1.775 - OG)) × (FG / 0.794)
Apparent Attenuation: ((OG - FG) / (OG - 1)) × 100
The calculator also applies a hydrometer temperature correction. This helps when the sample temperature differs from the tool calibration temperature.
How to Use This Calculator
Enter the original gravity before fermentation starts. Then enter the final gravity after fermentation ends. Select the formula type you prefer. Use the advanced formula for stronger batches. Use the standard formula for quick brewing records.
Add the sample temperature and calibration temperature. This improves accuracy for hydrometer readings. Enter batch volume and serving size. The calculator estimates servings, alcohol per serving, calories, and attenuation. Press the calculate button. The result appears above the form and below the header.
Specific Gravity to Alcohol Guide
Why Gravity Matters
Specific gravity shows how dense a liquid is compared with water. In brewing, sugar raises gravity. Yeast consumes that sugar during fermentation. Alcohol and carbon dioxide are then produced. A starting reading is called original gravity. A finishing reading is called final gravity. The difference between them helps estimate alcohol content.
Better Batch Control
This calculator gives more than a basic alcohol number. It also estimates attenuation, calories, servings, and alcohol per serving. These details help improve records. They also make batch comparison easier. A brewer can compare recipes, yeast performance, and fermentation progress with less guesswork.
Temperature Correction
Hydrometers are usually calibrated at a fixed temperature. A warm or cool sample can shift the reading. This calculator includes a temperature correction factor. The corrected readings are then used in the selected formula. That makes the result more dependable.
Choosing a Formula
The standard formula is simple and common. It works well for normal strength fermentations. The alternate formula gives a slightly different quick estimate. The advanced formula is helpful for stronger batches. It adjusts the relationship between gravity loss and alcohol more carefully.
Reading the Output
Alcohol by volume shows the estimated strength. Apparent attenuation shows how much sugar seems fermented. Higher attenuation often means a drier finish. Calories are only an estimate. Ingredients, residual sugars, and recipe style can change the real value. Use the result as a planning guide.
Record Keeping
Good records improve future recipes. Save the CSV file for spreadsheets. Save the PDF file for batch sheets. Record tasting notes beside the gravity data. Over time, these notes show patterns. They can reveal yeast behavior, mash efficiency, and fermentation consistency.
FAQs
What is original gravity?
Original gravity is the specific gravity before fermentation begins. It shows the dissolved sugar level available for yeast activity.
What is final gravity?
Final gravity is the reading after fermentation finishes. It helps measure how much sugar remains in the finished liquid.
Which ABV formula should I choose?
Use the standard formula for quick estimates. Use the advanced formula for stronger batches or more careful brewing records.
Why is temperature correction included?
Hydrometer readings change with sample temperature. Correction adjusts readings toward the calibration temperature for better accuracy.
Can final gravity be higher than original gravity?
No. For alcohol estimation, final gravity must be lower than original gravity. Otherwise, fermentation loss cannot be calculated correctly.
Are calorie estimates exact?
No. Calories are approximate. Residual sugars, ingredients, alcohol level, and serving size can all affect the final calorie count.
What does attenuation mean?
Attenuation shows how much extract appears fermented. Higher values usually suggest a drier and more fully fermented batch.
Can I save the result?
Yes. Use the CSV download for spreadsheets. Use the PDF download for batch notes, printed records, or recipe files.