Strike Water Temperature Calculator | Hit Your Mash Temp on the First Pour
When you mash in for an all-grain batch, cool grain pulls heat out of your hot water and the temperature drops on contact. To land on your target mash rest, you have to start hotter than the target by exactly the right amount. This tool runs the Palmer initial-infusion formula on your grain weight, grain temperature, and water-to-grain ratio, and also tells you the total water volume to heat.
💡 About this tool
Mash temperature steers the body of your beer. Around 64°C (147°F) you get a drier, more fermentable wort; around 68°C (154°F) you keep more dextrins for a fuller, sweeter beer. Miss your target by a couple of degrees and the whole character of the batch shifts, so dialing in the mash-in temperature is the first checkpoint of an all-grain day.
Grain holds about 41% as much heat as the same mass of water, so it warms up slowly and steals heat from your strike water. This calculator estimates that heat loss from your ratio and returns the strike temperature that settles to your target after you stir the grain in. It also shows the total strike water (ratio multiplied by grain weight) so you know how much to heat in the first place.
🧐 Frequently Asked Questions
I poured at the calculated temperature but landed below target. Why? A cold mash tun is the usual culprit. The vessel absorbs heat from the water, so even a perfect strike temp can drop a few degrees on contact with cold walls. Preheat by filling the tun with hot water, waiting about two minutes, then draining before you add grain. A thick-walled cooler may need only 0–2°F above the formula result, while a thin stainless pot on a cold stand can need 3–5°F extra.
What if I overshoot and land above target? Add cold water in small measured amounts, stir thoroughly, and re-check between additions; a couple of ice cubes work too. Cooling down is easier than reheating, so striking slightly hot makes the correction simpler.
How do I measure grain temperature? Use the room temperature of your crushed malt as-is. Grain stored in a cold garage reads low; grain kept at summer room temperature reads high. The colder the grain, the hotter your strike water needs to be, so this changes with the season.
What ratio should I use? A typical all-grain mash runs about 1.25 qt/lb (2.6 L/kg). A thinner mash (more water) drops less in temperature; a thicker mash (less water) drops more. Move the slider to watch how the strike temperature responds.
📚 Why the ratio changes everything
The reason a thick mash and a thin mash need different strike temperatures comes down to thermal mass. More water relative to grain means there is more hot mass to absorb the grain's heat demand, so the mix barely cools; less water means the same cold grain has less heat to draw from, so the drop is larger. That is why brewers who switch from a thick infusion mash to a high-water Brew-in-a-Bag setup often find their old strike numbers run cold. Recalculating for the new ratio, rather than reusing a memorized temperature, is what keeps your mash landing where you want it.