Pasteurisation Units Calculator
Convert hold temperature and hold time into pasteurisation units with the formula PU = t x 10^((T - Tref) / z), then compare the result with common packaged-beer planning bands and hold-time trade-offs.
Process Inputs
Enter the hold temperature and hold time to convert one flat process segment into equivalent reference-temperature minutes.
Quick Scenarios
PU Summary
Pasteurisation units
19.31 PU
Common planning band: Often aligns with routine packaged-beer planning checks when 5 to 25 PU is the working window.
Lethal rate multiplier
1.93x
Equivalent time at reference
19.31 min
Time to 15 PU
7.77 min
Time to 25 PU
12.95 min
This lands inside a common packaged-beer planning range. Use it as a line check, then confirm against your product, package, micro load, and shelf-life target instead of treating the number as a universal rule.
Detailed Breakdown
Current process math
Lethal rate = 10^((62 - 60) / 7)
PU = 10 x 1.93
Result: 19.31 PU
Hold-time targets at this temperature
15 PU requires about 7.77 min
25 PU requires about 12.95 min
Use these as process checks, not as universal product rules.
| Metric | Value |
|---|---|
| Hold temperature | 62 C |
| Hold time | 10 min |
| Reference temperature | 60 C |
| z-value | 7 C |
| Temperature lift above reference | 2 C |
| Lethal rate multiplier | 1.93x |
| Pasteurisation units | 19.31 PU |
| Time to 5 PU | 2.59 min |
| Time to 15 PU | 7.77 min |
| Time to 25 PU | 12.95 min |
| Time to 40 PU | 20.72 min |
Assumption notes
- This calculator assumes one flat hold segment, not a full tunnel temperature profile.
- The default reference temperature of 60 C and z-value of 7 C are common beer assumptions, not universal beverage constants.
- Equivalent reference time is a planning translation, not a substitute for micro validation or forcing tests.
Current scenario highlights
- Status: Common packaged-beer range
- Current hold: 62 C for 10 min
- Equivalent reference time: 19.31 min
Editorial & Review Information
Reviewed on: 2026-03-15
Published on: 2025-12-01
Author: LumoCalculator Editorial Team
What we checked: Formula math, example arithmetic, planning-band wording, and source accessibility.
Purpose and scope: This page is for beverage heat-treatment planning and line checks. It does not replace challenge studies, forcing tests, or a product-specific validation protocol.
How to use this review: Match the reference temperature and z-value to your internal method, calculate one hold segment, and compare the result with your validated PU window before changing a live setpoint.
Use Scenarios
Tunnel setpoint review
Check whether a hold zone, warmest package point, or dwell-time assumption is still landing inside the PU range your brewery already validates.
Flash hold verification
Translate short, high-temperature flashes into equivalent reference-time so a seconds-based process can be compared with a lower-temperature hold.
Shelf-life versus quality trade-off
Pressure-test whether extra heat is buying useful microbiological protection or mostly increasing flavor, aroma, and color risk.
Formula Explanation
1) Core PU equation
PU = t x 10^((T - Tref) / z)
t is hold time in minutes, T is product temperature, Tref is the reference temperature, and z is the temperature change required for a 10-fold change in lethal rate.
2) Why the rate changes so fast
Lethal rate = 10^((T - Tref) / z)
When the z-value is 7 C, moving 7 C above the reference makes the lethal rate 10x higher. That is why a hotter flash section can generate the same PU in seconds instead of minutes.
3) How to read equivalent time
Equivalent reference time = PU minutes at Tref
A result of 19.3 PU means the process delivered the same lethality as 19.3 minutes at the reference temperature. This makes low-temperature holds and high-temperature flashes comparable on one scale.
How to Read the Result
Below 5 PU
Minimal treatment. Useful as a quick stress check, but usually below routine packaged-beer planning ranges.
5 to 15 PU
Lighter treatment. Often used when freshness matters and the line is already tightly controlled.
15 to 25 PU
Common packaged-beer planning band in many brewing discussions, with 15 PU frequently used as a reference point rather than a universal rule.
Above 25 PU
Heavier protection. It may support tougher stability goals but also increases the chance of sensory trade-offs and unnecessary heat load.
Example Cases
Case 1: Standard tunnel beer check
Inputs
- Temperature: 62 C
- Hold time: 10 min
- Reference: 60 C
- z-value: 7 C
Computed Results
- Lethal rate: 1.93x
- PU: 19.31 PU
- Equivalent time: 19.31 min
- Time to 25 PU at same temperature: 12.95 min
Interpretation
The line lands inside a common packaged-beer planning range without pushing into a heavy overprocessing zone.
Decision Hint
Keep the setpoint if shelf-life and sensory checks are already passing, then trend the real tunnel profile instead of increasing heat by habit.
Case 2: Flash hold verification
Inputs
- Temperature: 72 C
- Hold time: 18 sec
- Reference: 60 C
- z-value: 7 C
Computed Results
- Lethal rate: 51.79x
- PU: 15.54 PU
- Equivalent time: 15.54 min
- Time to 25 PU at same temperature: 28.8 sec
Interpretation
A very short hold can still reach a meaningful PU target because the lethal-rate multiplier is much higher at 72 C.
Decision Hint
If sterile filling or downstream hygiene is strong, verify the actual hold section and sensor placement before extending the hold time.
Case 3: Extended shelf-life push
Inputs
- Temperature: 63 C
- Hold time: 10 min
- Reference: 60 C
- z-value: 7 C
Computed Results
- Lethal rate: 2.68x
- PU: 26.83 PU
- Equivalent time: 26.83 min
- Time to 25 PU at same temperature: 9.32 min
Interpretation
The process clears a common packaged-beer range and moves into a heavier protection band where flavor trade-offs matter more.
Decision Hint
Use lab, forcing, and sensory evidence to confirm the extra heat is worth the stability gain before locking the recipe or package spec.
Boundary Conditions
Sources & References
- GEA - GEA ECO-FLASH Pasteurization System - Process-equipment context for flash pasteurization, PU control, and the practical difference between temperature exposure and final validated heat load.
- Brewers Association - Pasteurization: Getting Started With the Basics - Process framing for brewery teams, including the role of validated targets, product differences, and practical pasteurization planning.
- Brewers Association - Foundations of Pasteurization for Regular and Non-Alcohol Beers - Presentation-level detail on z-value choice, regular versus non-alcohol beer sensitivity, and why validated targets move with product risk.
- Calculator Academy - Pasteurisation Units Calculator - Secondary formula walkthrough and example arithmetic used to cross-check the calculator math and notation.