Mash Strike Water Calculator

Frequently Asked Questions

How do I calculate mash strike water temperature?

Use Tw = (0.2 ÷ R)(T2 − T1) + T2, where R is the water-to-grain ratio in qt/lb, T1 is grain temperature, and T2 is target mash temperature. The 0.2 is the grain's specific heat relative to water.

What does the 0.2 constant represent?

It is the approximate thermal mass of malt relative to water (grain absorbs heat at about one-fifth the rate of equal-weight water). That is why hot strike water cools when it hits the grain.

Worked example for a single infusion mash?

For R = 1.25 qt/lb, grain at 65°F, target 152°F: Tw = (0.2 ÷ 1.25)(152 − 65) + 152 = 0.16 × 87 + 152 ≈ 166°F strike water.

Why is my actual mash temperature off?

Cold mash tuns and tubing steal heat, so preheat the vessel or aim 1–3°F higher than calculated. A thicker mash (lower R) holds temperature better but needs hotter strike water.

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Estimates for informational purposes only.

Important Disclaimer: Estimates for informational purposes only.

This calculator provides estimates for informational purposes only. Results are based on assumptions and may not reflect actual outcomes. Consult qualified professionals in relevant fields before making important decisions based on these results.

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How This Calculator Works

Enter your grain weight, the water-to-grain ratio, the temperature of your grain, and your target mash temperature. The calculator returns the strike water temperature - how hot to heat your water before mixing - and the strike volume to collect. Because the cool grain pulls heat out of the water, strike water must start hotter than the mash target. It supports US and metric units for all-grain homebrewers.

This is an informational brewing tool, not drinking advice - brew and enjoy responsibly, and know your limits.

Formula / Method

The standard strike-temperature equation is T_w = (0.2 ÷ R)(T₂ − T₁) + T₂, where R is the water-to-grain ratio (qt/lb or L/kg), T₁ is the grain temperature, and T₂ is the target mash temperature. The 0.2 is the ratio of grain's specific heat to water's. Strike volume is simply ratio × grain weight, converted to gallons or liters. A thinner mash (higher R) needs a smaller temperature boost; a thick mash needs a bigger one.

Worked Example

For 10 lb of grain at 68°F, a 1.25 qt/lb ratio, and a 152°F target: T_w = (0.2 ÷ 1.25)(152 − 68) + 152 = 0.16 × 84 + 152 ≈ 13.4 + 152 = 165.4°F. Strike volume = 1.25 × 10 = 12.5 qt ≈ 3.13 gal. Heat 3.13 gallons to about 165°F, then dough in - the grain pulls the mash down to roughly your 152°F target. Always stir well and check with a calibrated thermometer.

Common Mistakes

Ignoring a cold mash tun - an unheated cooler steals several degrees, so preheat it or aim a couple degrees higher.

Using the wrong ratio units; this formula expects qt/lb (US) or the L/kg equivalent (metric).

Forgetting that grain temperature changes with the seasons - cold winter grain needs hotter strike water.

Not stirring thoroughly, leaving hot and cold pockets that read an inaccurate average temperature.

Treating the result as exact; equipment heat loss varies, so calibrate to your own system over a few brews.

Tips & FAQ

What mash temperature should I target? 148–154°F (64–68°C) is typical - lower for a drier, more fermentable wort, higher for a fuller body. What ratio is normal? 1.25–1.5 qt/lb (2.6–3.1 L/kg) for most batch-sparge mashes. Why is my mash too cool? Usually a cold tun or unstirred grain; preheat and stir. Should I add a fudge factor? Many brewers add 1–2°F to the strike temp to offset tun loss. Dial the formula to your equipment after a brew or two and it becomes very repeatable.

Mash Strike Water Calculator

Frequently Asked Questions

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