Example Data Table
| Batch | Grain | Thickness | Strike Water | Sparge Water | Total Water |
|---|---|---|---|---|---|
| Small ale | 8 lb | 1.25 qt/lb | 2.50 gal | 4.05 gal | 6.55 gal |
| Standard ale | 12 lb | 1.35 qt/lb | 4.05 gal | 3.70 gal | 7.75 gal |
| Strong batch | 18 lb | 1.50 qt/lb | 6.75 gal | 2.85 gal | 9.60 gal |
Formula Used
Strike water: grain weight in pounds × mash thickness in qt/lb ÷ 4.
Grain absorption: grain weight in pounds × absorption rate in gal/lb.
First runnings: strike water − grain absorption − mash tun dead space.
Boil off: boil off rate per hour × boil time in hours.
Hot post-boil target: target fermenter volume plus trub loss, divided by cooling shrinkage factor.
Pre-boil target: hot post-boil target + boil off volume.
Sparge water: pre-boil target − first runnings. Negative values are shown as zero.
Strike temperature: ((0.2 ÷ mash thickness) × (target mash temperature − grain temperature)) + target mash temperature.
How To Use This Calculator
- Enter the total grain weight for your mash.
- Select the grain unit and water volume unit.
- Add the mash thickness used by your recipe.
- Enter grain absorption and mash tun dead space.
- Add fermenter target volume, trub loss, boil off, and boil time.
- Enter target mash temperature and grain temperature.
- Press the calculate button to view the water plan.
- Use CSV or PDF download buttons to save the result.
Mash Water Volume Guide
Mash Water Planning Matters
Mash water planning matters. A mash starts with grain and hot liquor. The ratio controls mash thickness. It also affects enzyme access, heat stability, and runoff behavior. Too little water can make stirring hard. Too much water can reduce sparge room. This calculator builds a practical plan before heating begins.
What The Estimate Covers
The tool starts with grain weight and the chosen thickness. That gives strike water. Then it estimates water held by the grain. Mash tun dead space is removed from first runnings. The remaining amount shows what you may collect before sparging. Next, it estimates a hot pre-boil target from fermenter volume, trub loss, cooling shrinkage, boil off rate, and boil time.
Why Advanced Losses Help
Many simple tools only multiply grain by a ratio. That is useful, but it can miss real brew house losses. Grain absorbs water. Some wort stays below the false bottom. Some wort remains with hops, break, or chiller tubing. Hot wort also contracts when cooled. These small losses can add up. A planned sparge amount helps reduce missed kettle volume.
Strike Temperature Guidance
The strike temperature result is an estimate. It uses grain temperature, target mash temperature, and mash thickness. Cooler grain needs hotter strike water. Thinner mash needs less temperature lift. Equipment heat loss is not included, so preheating the tun can improve accuracy. Always measure and adjust with a trusted thermometer.
Using The Results
Treat the result as a starting plan. Round volumes to marks on your kettle or bucket. Keep notes after each brew. Update absorption, dead space, and boil off values from real measurements. After two or three sessions, the calculator can match your system more closely. This improves consistency. It also makes recipe scaling easier.
Good Brewing Practice
Add water first when your process allows. Stir the grain slowly to prevent dry pockets. Check mash temperature after a short rest. Vorlauf until runoff clears. Then collect first runnings and sparge as planned. If the kettle volume is low, add water carefully. If it is high, extend the boil. Careful records create better volume control over time. For larger batches, confirm vessel capacity before filling. Leave safe headspace for stirring, foam, and easy transfer during active lautering.
FAQs
What is mash water?
Mash water is the hot water mixed with crushed grain. It hydrates the grain and helps enzymes convert starch into fermentable sugars during the mash rest.
What is strike water?
Strike water is the first hot water added to the mash. Its volume depends on grain weight and mash thickness. Its temperature helps reach the target mash temperature.
What is sparge water?
Sparge water rinses sugars from the grain bed after first runnings. The calculator estimates it from your pre-boil target and expected first runnings.
Why include grain absorption?
Grain holds water after draining. Absorption changes with crush, grain type, and system design. Including it gives a better estimate of collected wort volume.
Why include mash tun dead space?
Dead space is liquid left below the pickup or false bottom. It lowers collectable first runnings, so sparge water may need to increase.
What mash thickness should I use?
Many recipes use about 1.25 to 1.50 qt/lb. Metric users often work near 2.6 to 3.1 L/kg. Your process may need a different ratio.
Is the strike temperature exact?
No. It is an estimate. Mash tun heat loss, grain moisture, stirring speed, and thermometer accuracy can change the real temperature.
Can I use liters instead of gallons?
Yes. Select liters as the water volume unit. The calculator converts internal values and displays strike water, sparge water, and totals in liters.