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Pasteurisation Units Calculator

📅Last updated: December 1, 2025
✓Reviewed by: LumoCalculator Team

Calculate Pasteurisation Units (PU) for beer, juice, and other beverages. Determine heat treatment effectiveness based on temperature and time, with lethal rate calculations and process recommendations.

Calculate PU

Enter process parameters

Typical: 60-72°C for beer

Advanced Options

Standard: 60°C for beer

Standard: 7°C (temperature change for 10× rate change)

Pasteurisation Results

Pasteurisation Units:51.79 PU
High✓ Adequate
Lethal Rate
5.18
at process temperature
Equivalent Time
51.79 min
at 60°C reference
✓ Recommendation

High pasteurisation level suitable for juice and fruit beverages. May cause flavor changes in beer.

Calculation Steps

Formula:
PU = t × 10^((T - T_ref) / z)
L = 10^((65 - 60) / 7) = 10^(0.7143) = 5.1795
PU = 10 × 5.1795 = 51.79
Equivalent time at 60°C = 51.79 minutes

Related Calculators

What are Pasteurisation Units?

Pasteurisation Units (PU) are a standardized measure of heat treatment effectiveness used primarily in the brewing and beverage industry. One PU is defined as one minute of exposure at the reference temperature of 60°C (140°F).

Key Concepts

  • ✓1 PU: One minute at 60°C reference temperature
  • ✓Lethal Rate: Kill rate relative to reference temperature
  • ✓Z-Value: Temperature change for 10× rate change (7°C for beer)
  • ✓Exponential Effect: Higher temps dramatically reduce time needed

Recommended PU Targets

Product/ProcessPU RangeTypical Conditions
Tunnel Pasteurisation (Beer)15-30 PU60-65°C for 15-30 min
Flash Pasteurisation (Beer)30-50 PU72-74°C for 15-30 sec
Draft Beer50-100 PUHigher for longer keg life
Fruit Juice50-100 PUHigher acidity organisms
Cider25-50 PUSimilar to beer requirements

Note: Actual requirements depend on product pH, packaging type, target shelf life, and regional regulations.

The PU Formula

Pasteurisation Units Formula

PU = t × 10((T - Tref) / z)
t = Treatment time (minutes)
T = Process temperature (°C)
Tref = Reference temperature (60°C for beer)
z = Z-value (7°C for beer)

Calculation Steps:

  1. 1
    Calculate Temperature Difference
    Find (T - T_ref): Process temp minus reference temp
  2. 2
    Calculate Lethal Rate
    L = 10^((T - T_ref) / z) - the kill rate multiplier
  3. 3
    Multiply by Time
    PU = time × lethal rate

Pasteurisation Methods

🌊 Tunnel Pasteurisation

Filled containers pass through heated water zones

  • • Temperature: 60-65°C
  • • Time: 15-30 minutes
  • • PU: 15-30
  • • Best for: Bottles, cans
⚡ Flash Pasteurisation

Rapid heating before sterile packaging

  • • Temperature: 72-74°C
  • • Time: 15-30 seconds
  • • PU: 30-50
  • • Best for: Kegs, bulk
🔥 HTST (High-Temp Short-Time)

Standard dairy-style pasteurisation

  • • Temperature: 72°C
  • • Time: 15 seconds
  • • Used for: Milk, juice
  • • Preserves nutrients better
🥶 Cold Pasteurisation

Non-thermal alternatives

  • • Methods: UV, HPP, irradiation
  • • No heat damage
  • • Fresh flavor retention
  • • Higher equipment cost

Temperature vs Time Trade-off

⚠️ Key Principle

Every 7°C increase in temperature reduces required time by 90% (10-fold) to achieve the same PU. This is why flash pasteurisation works in seconds!

TemperatureLethal RateTime for 20 PU
60°C (reference)1.020.0 minutes
63°C2.687.5 minutes
65°C5.183.9 minutes
67°C (z-value)10.02.0 minutes
72°C51.823 seconds
74°C (2×z)100.012 seconds

Quality Considerations

✓ Benefits of Higher PU
  • • Better microbiological stability
  • • Longer shelf life
  • • Safer for export/distribution
  • • Reduced spoilage risk
✗ Drawbacks of Higher PU
  • • Flavor changes (cooked notes)
  • • Color darkening
  • • Hop aroma loss
  • • Higher energy costs
🎯 Best Practice
  • • Use minimum PU for target shelf life
  • • Prefer higher temp, shorter time
  • • Monitor and validate regularly
  • • Consider product-specific needs
🧪 Quality Testing
  • • Forcing tests for shelf life
  • • Microbiological counts
  • • Sensory evaluation
  • • PU logger validation

Frequently Asked Questions

What are Pasteurisation Units (PU)?
Pasteurisation Units (PU) are a measure of heat treatment effectiveness in beverages, particularly beer. One PU equals one minute of exposure at 60°C (140°F). The PU value accounts for both temperature and time, allowing comparison of different pasteurisation processes. Higher temperatures achieve the same PU in less time due to increased microbial kill rates.
How many PU are needed for beer pasteurisation?
For standard beer tunnel pasteurisation, 15-30 PU is typically required. Flash pasteurisation may use 30-50 PU. The exact requirement depends on the beer type, packaging, desired shelf life, and regulatory requirements. Craft beers may use lower PU to preserve flavor, while export beers may need higher PU for extended stability.
What is the z-value in pasteurisation?
The z-value represents the temperature change required to achieve a 10-fold (one log) change in the lethal rate. For beer pasteurisation, the standard z-value is 7°C. This means increasing temperature by 7°C will reduce the required pasteurisation time by 90% to achieve the same PU. Different organisms have different z-values.
How do I calculate PU for my process?
PU is calculated using the formula: PU = t × 10^((T - T_ref) / z), where t is time in minutes, T is process temperature in °C, T_ref is reference temperature (60°C for beer), and z is the z-value (7°C standard). Our calculator automates this calculation and shows step-by-step results.
What is the difference between tunnel and flash pasteurisation?
Tunnel pasteurisation heats filled containers (bottles/cans) in a water tunnel at 60-65°C for 15-30 minutes, achieving 15-30 PU. Flash pasteurisation rapidly heats beer to 72-74°C for 15-30 seconds before packaging, achieving 30-50 PU. Flash is faster and uses less energy but requires sterile filling. Tunnel is gentler on flavor.
Why does temperature matter more than time in pasteurisation?
Temperature has an exponential effect on microbial kill rate. Increasing temperature by one z-value (7°C for beer) increases lethal rate 10-fold. A 5-degree increase doubles the lethal rate. This means small temperature increases dramatically reduce required time. This is why flash pasteurisation at 72°C needs only seconds, while tunnel at 60°C needs 20+ minutes.