Strike Water Temperature Calculator

This tool computes the strike water temperature required to hit your target mash temperature on a single-infusion mash. It supports US and Metric units and shows the exact equation with a line-by-line example for transparency and reproducibility.

How to use

  1. Select Units (US or Metric).
  2. Enter your Target mash temperature and the current Grain temperature.
  3. Set the Mash thickness (water-to-grain ratio). Optionally enter your Grain bill to compute the starting strike volume.
  4. Optionally apply a small Mash tun correction if your tun is unusually cold/hot.
  5. Read the results instantly. Use Copy link to share or bookmark your setup.

Calculation formulas

US units (°F, qt/lb):

$$T_w \;=\; \left(\frac{0.2}{R}\right)\,(T_2 - T_1)\;+\;T_2$$

where \(T_w\) is strike water temperature, \(T_2\) is the desired mash temperature, \(T_1\) is the current grain temperature, and \(R\) is the mash thickness in qt/lb.

Metric (°C, L/kg):

$$T_w \;=\; \left(\frac{0.41}{R}\right)\,(T_2 - T_1)\;+\;T_2$$

The constant (~0.41) reflects grain’s heat capacity relative to water and unit conversion when using L/kg.

Why 0.2 and 0.41?

Following John J. Palmer, grain has roughly 40% of the heat capacity of water. In US customary units with qt/lb the expression uses 0.2; in metric with L/kg it appears as about 0.41. See sources below for the exact statement and derivation.

Worked example

Goal: Mash at 152 °F with grain currently at 68 °F, ratio 1.25 qt/lb.

US equation: \(T_w = (0.2/R)(T_2 - T_1) + T_2\)

\(T_w = \big(0.2 / 1.25\big)\,(152 - 68) + 152 = 0.16 \times 84 + 152 = 13.44 + 152 = \mathbf{165.44\,^\circ F}\)

If your tun is quite cold, pre-heat it (e.g., with hot water) or add a small correction (e.g., +1 °F).

Glossary

  • Strike water: The hot water used for the initial infusion of the mash.
  • Mash thickness (R): Water-to-grain ratio; qt/lb (US) or L/kg (Metric).
  • Target mash temperature (T₂): Desired rest temperature for enzymatic activity.
  • Grain temperature (T₁): Actual temperature of milled grain before dough-in.

Authoritative sources

  • Palmer, J. J. — How to Brew, “Mash Methods / Infusion Equations.” Metric presentation uses \(0.4\) (≈0.41) with \(R\) in L/kg and explains the heat-capacity rationale. :contentReference[oaicite:0]{index=0}
  • Homebrew Academy—summary of Palmer’s US formula with \(0.2\) and \(R\) in qt/lb. :contentReference[oaicite:1]{index=1}
  • Braukaiser Wiki—infusion mashing page referencing Palmer’s strike temperature equation. :contentReference[oaicite:2]{index=2}
  • Brewer’s Friend—usage notes on strike water and acceptable miss ranges (±2 °F / ±1 °C). :contentReference[oaicite:3]{index=3}

Practical tips

  • Stir thoroughly and measure after 2–3 minutes of stabilization.
  • If you miss by a small margin (±2 °F | ±1 °C), keep mashing; larger misses → adjust with small additions of boiling/cold water in steps. :contentReference[oaicite:4]{index=4}
  • Record your system’s typical correction (e.g., +1 °F) to reuse next time.