Strike Water Calculator
Updated — 2026
Strike Water Calculator: Temperature and Volume for Mashing
Use this strike water calculator to find the exact water temperature and volume you need to hit your target mash temperature on the first try. Enter your grain weight, the current temperature of your grain, your target mash temperature, and your water-to-grain ratio — the calculator accounts for the thermal mass of the grain so the water doesn’t just match your target, it actually gets you there once the two are mixed. Works for traditional mash tuns, coolers, and BIAB (Brew in a Bag) setups alike.
Strike water temp
Strike water volume
Heat above target
Taking a gravity reading straight from a warm mash or wort? A hot sample throws off a hydrometer’s reading — correct it first with the Hydrometer Temperature Correction Calculator before you write your numbers down.
How to Use This Strike Water Calculator
- Enter your grain weight — the total grain bill for the batch you’re mashing.
- Enter your grain’s current temperature — almost always room temperature, unless your grain has been stored somewhere warmer or colder.
- Pick a mash profile or enter your own target — choose a profile from the dropdown for a sensible default, or type your target mash temperature directly.
- Select your mash tun heat loss — a bare metal pot or uninsulated cooler pulls more heat from the strike water than a preheated one, so add a small correction if that applies to your setup.
- Choose your mash thickness or enter a custom ratio — thicker mashes use less water per pound of grain, thinner mashes (and BIAB) use more.
- Click Calculate to see your exact strike water temperature and volume.
Once you’ve mixed water and grain, stir thoroughly and wait a few minutes before taking your real mash temperature reading — a fresh dough-in reading is often misleading until everything has evened out.
Understanding Your Results
Why Strike Water Has to Be Hotter Than Your Mash Target
Grain absorbs heat the moment it hits water, which pulls the temperature of the mixture down below the temperature of the water alone. The colder your grain and the more grain relative to water, the bigger that drop. This calculator works out exactly how much hotter than your target the water needs to start, so that once it’s fully mixed with your grain, the resulting mash settles right where you want it.
The Strike Water Formula
The calculator is built on a heat-balance formula that’s been used by homebrewers since it was first popularized at a late-1980s American Homebrewers Association conference. In its commonly cited imperial form:
where R = water-to-grain ratio in quarts per pound
The constant 0.2 comes from the ratio between the specific heat of grain and the specific heat of water — grain holds roughly 0.4 as much heat per degree as an equal mass of water, and this calculator applies that same heat-balance principle directly in metric units for its internal math, so the result stays accurate whether you’re working in pounds and Fahrenheit or kilograms and Celsius.
Volume Formula
This is simply your chosen ratio multiplied by how much grain you’re mashing — a thicker mash (lower ratio) needs less water, a thinner mash or full-volume BIAB (higher ratio) needs more.
Water-to-Grain Ratios by Mash Style
These are typical starting ranges — your ideal ratio depends on your equipment and how thick or thin you like to mash. You can always enter your own ratio directly in the calculator above.
| Mash type | Ratio (qt/lb) | Ratio (L/kg) | Notes |
|---|---|---|---|
| Thick / traditional | 1.0 – 1.25 | 2.1 – 2.6 | Higher stuck-sparge risk, less total sparge water |
| Standard single-infusion | 1.25 – 1.5 | 2.6 – 3.1 | Most common default for homebrew setups |
| Thin mash | 1.5 – 1.75 | 3.1 – 3.65 | Easier to stir and pump, steadier temperature |
| BIAB, full volume | 2.0 – 3.0 | 4.2 – 6.3 | All brewing water used as mash water, no separate sparge |
| Decoction / step mash-in | 0.75 – 1.0 | 1.6 – 2.1 | Thicker so portions can be pulled and boiled without scorching |
Strike Water Volume Quick Reference
Want a rough number before you run the full calculator? This chart shows strike water volume in quarts (US gallons in parentheses) for common grain bill weights at three typical ratios. If your grain weight or ratio falls between rows, use the calculator above for an exact figure.
| Grain weight | 1.25 qt/lb (thick) | 1.5 qt/lb (standard) | 1.75 qt/lb (thin) |
|---|---|---|---|
| 5 lb (2.3 kg) | 6.25 qt (1.56 gal) | 7.5 qt (1.88 gal) | 8.75 qt (2.19 gal) |
| 10 lb (4.5 kg) | 12.5 qt (3.13 gal) | 15 qt (3.75 gal) | 17.5 qt (4.38 gal) |
| 12 lb (5.4 kg) | 15 qt (3.75 gal) | 18 qt (4.5 gal) | 21 qt (5.25 gal) |
| 15 lb (6.8 kg) | 18.75 qt (4.69 gal) | 22.5 qt (5.63 gal) | 26.25 qt (6.56 gal) |
| 20 lb (9.1 kg) | 25 qt (6.25 gal) | 30 qt (7.5 gal) | 35 qt (8.75 gal) |
This chart shows strike water volume only, not the strike temperature — temperature depends on your grain and target mash temp, so use the calculator above for that number.
Avoiding Common Strike Water Mistakes
Missing your mash temperature is one of the most common brew day frustrations — and almost always avoidable. A few habits make it far more consistent:
- Preheat uninsulated equipment. A cold metal pot or an unheated cooler pulls extra heat from your strike water before the grain even goes in — swirl a little near-boiling water through it first, or use the mash tun heat loss setting above.
- Calibrate your thermometer. Check it in ice water (should read 32°F / 0°C) and in a boil (should read close to 212°F / 100°C at sea level) so you know it’s telling you the truth.
- Stir thoroughly, then wait. Dough balls and uneven mixing can make an early reading swing several degrees either way — stir well and re-check after a few minutes.
- Use the right ratio for your method. BIAB brewers mashing at full volume need a noticeably higher ratio than a traditional two-vessel setup with a separate sparge.
- Log your actual results. If your real mash temperature consistently lands a degree or two off from this calculator, that gap is your equipment’s personal correction factor — use it next time.
Ready to move from mash to fermentation? Once you know your pitch volume and gravity, size your yeast addition correctly with the Yeast Pitch Rate Calculator.
Frequently Asked Questions About Strike Water
What is strike water temperature?
Strike water temperature is how hot your brewing water needs to be right before it meets the grain, so that once the two are mixed and the grain has pulled some heat out of the water, the resulting mash lands at your actual target rest temperature. It’s always higher than the mash temperature itself.
What is the strike water formula?
The most widely used version is Strike Temp (°F) = (0.2 ÷ R) × (T_target − T_grain) + T_target, where R is your water-to-grain ratio in quarts per pound. It’s based on a heat-balance calculation between the specific heat of grain and water — this calculator runs the same underlying physics for both imperial and metric units.
How much strike water do I need per pound of grain?
Most single-infusion mashes use 1.25–1.5 quarts of water per pound of grain (2.6–3.1 L/kg), with thicker mashes using less and thinner mashes using more. BIAB brewers mashing at full batch volume typically need 2–3 quarts per pound (4.2–6.3 L/kg) since there’s no separate sparge step.
Is the strike water calculation different for BIAB?
The underlying formula is the same, but the ratio is usually much higher for BIAB because all of your brewing water goes in at mash-in rather than being split between mash and sparge water. Select the BIAB option in the mash thickness dropdown above to auto-fill a typical full-volume ratio.
Do I need to preheat my mash tun?
Yes, especially if it’s an uninsulated metal vessel or an unheated cooler — cold equipment pulls extra heat out of your strike water before the grain is even added, which can leave your mash noticeably below target. Preheating with hot water first, or adding a mash tun heat loss correction like the one in this calculator, corrects for that.
What’s the difference between strike water and sparge water?
Strike water is the hot water mixed with grain at the start of the mash to hit your rest temperature; sparge water is the water used afterward to rinse remaining sugars from the grain bed. Strike water temperature is calculated to account for the grain’s thermal mass, while sparge water is usually held at a fixed temperature (around 168–170°F / 75–77°C) and its volume is set by how much pre-boil wort you still need.
What if my mash comes in too hot or too cold after mixing?
A few degrees off is normal and easy to fix. If the mash is too cold, add a small amount of near-boiling water and stir; if it’s too hot, add a splash of cool water. Note how far off you landed from this calculator’s prediction so you can dial in a personal correction factor for your equipment next time.
Can I use this calculator for step mashes or decoction?
Yes, for the initial dough-in step. Enter your first rest temperature as the target to get your strike water numbers, then handle later temperature steps separately — step mashes typically raise temperature with direct heat or infusions of boiling water rather than a second “strike,” and decoction mashing pulls out and boils a thick portion of the mash instead.
Why is my calculated strike temperature so much higher than my mash temperature?
This is expected with a thick mash or cold grain. The less water relative to grain, and the colder that grain is, the more heat it pulls out of the water — so a thick mash with cold grain can call for strike water 15–20°F (8–11°C) above the target, while a thin mash with warm grain might need only a few degrees more.
What temperature should I mash at for a drier vs. sweeter beer?
Lower mash temperatures (around 148–150°F / 64–66°C) favor beta-amylase and produce a more fermentable, drier wort, while higher temperatures (around 154–158°F / 68–70°C) favor alpha-amylase and leave more unfermentable sugar for a fuller, maltier body. Most ales land in between, around 150–154°F (66–68°C).