Canning Heat Penetration Testing: Loggers, Fittings & Method

Shelf-stable canned foods depend on a thermal process that reaches the slowest-heating point in the container. Heat penetration testing measures the temperature at that point during real retort or pasteurisation cycles, so you can prove the process delivers the required lethality — and adjust it with confidence.

Heat distribution vs heat penetration

• Heat distribution tests measure temperature around the containers, across the retort or vessel, to find its coldest zone.
• Heat penetration tests measure temperature inside the containers, at the product's cold spot, to determine how quickly the product heats.

Both are needed to establish and validate a thermal process.

The equipment

A canning process temperature logger must sit on the container with its probe inside, without leaking. That needs three things:

1. A heat penetration logger — the HiTemp140-CF is submersible, withstands up to 140 °C and is designed to attach to containers through a canning fitting.
2. A fitting that seals the container — the CF202 canning fitting mounts the HiTemp140-CF on jar lids, cans and other containers (the CF200 does the same for HiTemp140-FP, -PT and transitional diameter models).
3. A holder for difficult packaging — the ThermaLock supports cans, jars, bottles, Recart cartons and pouches, and keeps the probe tip precisely at the cold spot.

Method in brief

1. Find the cold spot. For conduction-heating foods (thick purées, solid packs) it is usually near the geometric centre; for convection-heating liquids it is usually lower down. Confirm with preliminary runs.
2. Prepare test containers. Fit the logger and fitting, fill with product exactly as in production, and seal.
3. Place test containers in the slowest-heating zone found by heat distribution testing.
4. Run the process under normal conditions, repeating across several runs.
5. Analyse the data. Calculate lethality (for low-acid foods, F0 at a reference of 121.1 °C) and confirm the process meets your target with a safety margin.

Tips for reliable results

• Use the shortest probe that reaches the cold spot — the probe should not touch the container wall.
• Check fitting seals every run; a leak changes how the product heats.
• Keep logger calibration current — see our calibration services.
• Replace batteries before critical studies; the HiTemp140 series uses the ER14250-01 battery.