Pasteurisation Units Calculator

Work out pasteurisation units instantly with clear inputs, formula shown and shareable results.

About Pasteurisation Units Calculator

One pasteurisation unit is one minute at the reference temperature, and the lethal rate at any other temperature is 10^((T - Tref)/z). Beer is usually assessed at 60 C with z = 7, where 15-30 PU is typical; juice and dairy use different reference and z values. PU accumulate through heating, holding and cooling.

Formula

Pasteurisation units

PU = time x 10^((T - T_reference) / z)

Worked example

With the default values below, Pasteurisation Units Calculator returns Pasteurisation Units of 38.6140. Change any input above and every figure here is recalculated in your browser.

Inputs used

Product Temperatureminimum 0 degrees C: 62 degrees C
Hold Timeminimum 0 minutes: 20 minutes
Reference Temperatureminimum 0 degrees C: 60 degrees C
z Valueminimum 0.1 degrees C: 7 degrees C

Results

Pasteurisation Units: 38.6140
Lethal Rate At Product Temperature: 1.93070
Minutes To Reach 100 PU: 51.7947
Equivalent Minutes At Reference: 38.6140

Step by step

1Values used
2Pasteurisation units
3Pasteurisation Units= 38.6140
4Lethal Rate At Product Temperature= 1.93070
5Minutes To Reach 100 PU= 51.7947
6Equivalent Minutes At Reference= 38.6140

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 5 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Pasteurisation schedules are food safety critical and must be validated against the target organism for the specific product and verified by continuous monitoring.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Pasteurisation schedules are food safety critical and must be validated against the target organism for the specific product and verified by continuous monitoring.

Frequently Asked Questions

Why do a few degrees matter so much?

With z = 7, every 7 degrees multiplies lethality by ten. Running at 67 C instead of 60 C delivers ten times the PU in the same time — and can over-pasteurise, damaging flavour.

Should heating and cooling be counted?

Yes. Integrating the lethal rate over the whole time-temperature profile typically adds 20-50% to the PU delivered in a tunnel pasteuriser compared with the hold phase alone.