A strike water calculator determines the exact temperature and volume of water needed to hit your target mash temperature in all-grain brewing. Using the Palmer infusion formula, it accounts for grain weight, grain temperature, and water-to-grain ratio so your mash starts at the right temperature for optimal enzyme activity and starch conversion.
Mash Parameters
Strike Water Results
Sparge & Pre-Boil Water
Grain absorption is estimated at 0.125 gal/lb (0.52 L/kg). Adjust boil-off rate based on your kettle and burner.
Step Mash Infusion
Calculate how much boiling water to add to raise your mash temperature for a step mash.
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Mash Temperature Guide
| Rest Type | Temp Range | Purpose |
|---|---|---|
| Acid Rest | 95-113 °F / 35-45 °C | Lowers mash pH (rarely used with modern malts) |
| Protein Rest | 113-138 °F / 45-59 °C | Breaks down proteins, improves clarity and head retention |
| Beta-Amylase | 140-150 °F / 60-65 °C | Produces fermentable sugars, drier/lighter beer |
| Alpha-Amylase | 150-160 °F / 65-71 °C | Produces unfermentable sugars, fuller body |
| Mash-Out | 168-170 °F / 76-77 °C | Stops enzyme activity, improves lautering flow |
How to Use the Strike Water Calculator
In all-grain brewing, the strike water calculator is one of the most important pre-brew-day tools. When you add hot water to crushed grain, the water temperature drops as the grain absorbs heat. If your water is not hot enough, you will undershoot your target mash temperature and get poor starch conversion. Too hot, and you risk killing the enzymes that convert starches into fermentable sugars. This calculator uses the Palmer infusion formula to tell you exactly what temperature your strike water needs to be.
Step 1: Enter your grain weight
Enter the total weight of your grain bill. This is the combined weight of all base malts and specialty grains. You can toggle between pounds and kilograms using the unit switch at the top. A typical 5-gallon batch uses 8-14 pounds (3.5-6.5 kg) of grain depending on the target gravity.
Step 2: Set your target mash temperature
Choose a mash temperature based on your desired beer character. Use the style presets for quick selection: Light/Dry (148 °F) emphasizes beta-amylase for a highly fermentable, dry wort; Medium (152 °F) provides a balanced blend of fermentable and unfermentable sugars; Full-Bodied (156 °F) favors alpha-amylase for a sweeter, fuller beer. You can also type in any custom temperature.
Step 3: Check grain temperature and ratio
The grain temperature defaults to room temperature (70 °F / 21 °C). If your grain is stored in a cold garage or warm attic, adjust accordingly — even a few degrees off can change your strike water temperature by several degrees. The water-to-grain ratio defaults to 1.33 qt/lb, which works well for most mash tuns. Adjust if your system requires a thinner or thicker mash.
Step 4: Review strike water results
The calculator shows your required strike water temperature, total strike water volume, and mash thickness. Heat your water to the strike temperature, then slowly add the grain while stirring to prevent dough balls. Stir the mash thoroughly and check the temperature after a minute or two to confirm you hit your target.
Step 5: Calculate sparge and pre-boil volumes
Enter your target batch size, boil time, and boil-off rate to calculate how much sparge water you need and your total pre-boil volume. The calculator accounts for grain absorption (approximately 0.125 gal per pound of grain) and equipment losses. Heat your sparge water to 168-170 °F and rinse the grain bed to collect the remaining sugars.
Step 6: Plan infusion steps (optional)
For a step mash, use the infusion section to calculate how much boiling water to add to raise your mash from one rest temperature to another. This is useful for traditional brewing styles like German lagers and Belgian ales that benefit from protein rests or step-mashing. All calculations are private and run entirely in your browser.
Frequently Asked Questions
Is this strike water calculator really free?
Yes, the strike water 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 brewing data is transmitted to any server, stored in any database, or shared with anyone.
What is the Palmer infusion formula?
The Palmer formula calculates the temperature your strike water needs to be so that when it mixes with room-temperature grain, the combined mash hits your target temperature. The formula is: Strike Temp = (0.2 / ratio) x (target - grain temp) + target, where ratio is quarts of water per pound of grain.
What water-to-grain ratio should I use?
Most all-grain brewers use a ratio between 1.25 and 1.5 quarts per pound. A thinner mash (higher ratio) is easier to stir and lauter, while a thicker mash (lower ratio) can produce a fuller-bodied beer. Start with 1.33 qt/lb and adjust based on your system and style.
Why is my actual mash temperature different from the target?
Several factors can cause a mismatch: heat loss to the mash tun (especially if not preheated), inaccurate grain temperature readings, or heat loss during transfer. Preheat your mash tun with hot water before doughing in, and account for any known temperature loss in your system.
What temperature should sparge water be?
Sparge water is typically heated to 168-170 degrees Fahrenheit (75-77 degrees Celsius). Going above 170 F risks extracting harsh tannins from the grain husks, which can cause astringent off-flavors in the finished beer.
How do I calculate an infusion step to raise mash temperature?
Use the step mash section of this calculator. Enter your current mash temperature, target temperature, and the calculator determines how much boiling water to add. The formula accounts for the thermal mass of both the grain and the existing mash water.
Does mash thickness affect enzyme activity?
Yes. A thinner mash (1.5+ qt/lb) favors beta-amylase, producing a more fermentable, drier beer. A thicker mash (1.0-1.25 qt/lb) favors alpha-amylase, producing a fuller-bodied beer with more residual sweetness. Mash temperature has a larger effect, but thickness plays a supporting role.