Mash Infusion and Strike Water Calculator

Strike water hits a target mash temperature by mixing hot water with room-temperature grain, and Palmer's infusion equation models that thermal exchange to return the water temperature and volume needed. The same model extends to multi-step infusion mashes, where boiling water is added to raise the mash to each successive rest temperature in turn.

Grain weight and either a water-to-grain ratio or an exact strike water volume set how much water is involved; common ratios run 1.0 to 2.0 quarts per pound (2.0 to 4.0 liters per kilogram). First rest temperature is the target mash temperature, with common saccharification rests running 148 to 158 degrees Fahrenheit (64 to 70 degrees Celsius). Grain temperature is typically room temperature, around 68 to 72 degrees Fahrenheit (20 to 22 degrees Celsius), though grain stored somewhere colder should use its actual measured temperature. Boiling temperature matters at altitude, since water boils below 212 degrees Fahrenheit (100 degrees Celsius) as elevation increases, dropping roughly 1 degree Fahrenheit per 500 feet.

The underlying formula is Strike Water Temperature = (0.2 / R) x (T_target - T_grain) + T_target + TunLoss, where R is the water-to-grain ratio in quarts per pound and 0.2 is the specific heat of grain relative to water. Mash tun heat loss, the heat absorbed by the tun's own walls, typically runs 2 to 5 degrees Fahrenheit and can be set to 0 for a tun that has been thoroughly pre-heated. For a multi-step mash, each additional target temperature after the first is reached by adding a calculated amount of boiling water rather than a fresh strike.

A single-infusion mash targets 152 degrees Fahrenheit starting from 68-degree grain at a 1.25 quarts-per-pound ratio, with a 3-degree tun heat loss. Strike Water Temperature = (0.2 / 1.25) x (152 - 68) + 152 + 3 = 0.16 x 84 + 155 = 13.44 + 155, or about 168.4 degrees Fahrenheit.

Mash schedules depend on hitting each rest temperature precisely, and strike water that is a few degrees off shifts the enzyme activity that sets a beer's fermentability and body. A single-infusion ale and a multi-step lager both start from the same calculation of how much water at what temperature to add.

• Single Infusion Mash: A straightforward saccharification rest at 152 degrees Fahrenheit with 12 pounds of grain and a 1.25 quarts-per-pound ratio needs an exact strike water temperature to hit that target on the first try.
• Multi-Step Infusion Mash: A traditional German-style mash with a protein rest at 122 degrees Fahrenheit, a beta-amylase rest at 146 degrees Fahrenheit, and a mash-out at 168 degrees Fahrenheit needs the boiling water addition calculated separately at each step.
• Brew in a Bag (BIAB): A higher water-to-grain ratio, 2.0 quarts per pound or higher, with mash tun heat loss set to 0 since the kettle is already heated, gives the precise strike temperature for a full-volume mash.
• Altitude Brewing: A lower boiling temperature at high-altitude locations changes infusion step calculations; a brewer at 5,000 feet would set boiling temperature to approximately 202 degrees Fahrenheit.
• Decoction Alternative: Infusion additions can step through temperature rests instead of pulling and boiling portions of the mash, with the required water volumes comparing the two techniques directly.
• Recipe Development: Testing different water-to-grain ratios shows how thinner or thicker mashes affect strike water temperatures and total mash volume, useful for optimizing ratios to a specific mash tun's capacity.
• Homebrew Education: Palmer's equation and the thermal relationship between grain, water, and target temperature become explicit in the step-by-step formula display, useful as a teaching aid for new brewers.