Formula Used
The calculator uses a standard infusion mash heat balance formula.
Strike Temp = Target Temp + ((Thermal Factor / Water Ratio) × (Target Temp - Grain Temp)) + Heat Loss + Tun Adjustment
For US inputs, a common grain thermal factor is 0.20. For metric inputs, a common value is 0.41. You may edit this value for your malt, system, or measured brewing notes.
How to Use This Calculator
Choose the unit system first. Enter your target mash rest temperature. Add the current grain temperature. Enter grain weight and mash thickness. Use heat loss if your water cools during transfer. Use tun adjustment when your mash vessel absorbs heat. Press calculate. The result appears below the header and above the form.
Example Data Table
| Batch |
Target |
Grain Temp |
Ratio |
Heat Loss |
Estimated Strike |
| Pale Ale |
152 °F |
68 °F |
1.25 qt/lb |
2 °F |
167.4 °F |
| Dry Stout |
154 °F |
66 °F |
1.35 qt/lb |
1 °F |
168.0 °F |
| Wheat Beer |
150 °F |
70 °F |
1.50 qt/lb |
2 °F |
162.7 °F |
| Metric Lager |
67 °C |
20 °C |
3.0 L/kg |
1 °C |
74.4 °C |
Strike Water Temperature Guide
Why Strike Temperature Matters
Strike water temperature controls the first mash rest. That rest shapes fermentability, body, and flavor. If the water is too cool, conversion may slow. If the water is too hot, enzymes can suffer. A planned strike temperature gives the brewer a better start.
Main Inputs
The target mash temperature is your desired rest. Grain temperature is the actual malt temperature before dough-in. Water ratio describes mash thickness. A thin mash needs less extra heat. A thick mash needs more. Grain weight is used to estimate water volume. It also helps document the batch.
System Adjustments
Every brewing setup behaves differently. Plastic coolers, metal kettles, and insulated tuns lose heat at different rates. Transfer distance also matters. The heat loss field lets you raise the strike water target. The tun adjustment field helps account for a cold or preheated vessel.
Thermal Factor
The default factor is based on common brewing practice. Use 0.20 for US mash ratios. Use 0.41 for metric mash ratios. These values are estimates. You can refine them after several brews. Compare the predicted rest with the measured rest. Then adjust the factor or offset.
Better Brewing Notes
Use the batch name field for tracking. Save a CSV file after each calculation. Download the PDF report for brew day records. Over time, your notes reveal patterns. You may learn that your tun absorbs two degrees. You may also find that winter grain needs warmer strike water.
Practical Brewing Advice
Always stir well after adding grain. Check temperature in more than one spot. Close the tun after mixing. Wait a short time before judging the rest. Mash temperature can settle after dough balls break apart. Small corrections are normal. Add hot or cool water only when needed.
FAQs
1. What is strike water temperature?
It is the hot water temperature before grain is added. It must be higher than the target mash rest because grain absorbs heat.
2. Why is grain temperature important?
Cold grain lowers mash temperature more than warm grain. Measuring grain temperature improves the strike water estimate.
3. What thermal factor should I use?
Use 0.20 for US ratios and 0.41 for metric ratios. Adjust the value after testing your real brewing system.
4. What does heat loss offset mean?
It adds extra temperature for cooling during transfer, waiting, or pouring. Use measured loss from your own brew day notes.
5. What is mash tun adjustment?
It accounts for heat absorbed or added by the mash vessel. A cold tun may need a positive adjustment.
6. Can this calculator use metric units?
Yes. Select metric, then enter temperature in Celsius, grain weight in kilograms, and ratio in liters per kilogram.
7. Why is my strike temperature above boiling?
Your mash may be very thick, your grain may be very cold, or the target may be high. Review the input values.
8. Can I export my result?
Yes. Use the CSV button for spreadsheet records. Use the PDF button after calculation for a simple brew report.