Fridge monitoring for restaurants and cafes.

What a restaurant or cafe fridge should hold

Cold potentially hazardous food belongs at 5°C or below, and most kitchens run their fridges at 2°C to 4°C for a safe margin. Freezers sit at minus 18°C or colder. The food safety danger zone runs from 5°C to 60°C, so the moment a fridge creeps past 5°C is the early warning worth catching, long before anything smells wrong.

The trouble in a real kitchen is not knowing the number, it is that nobody is free to check it every hour through a service. Between the lunch rush, a delivery and close, a fridge can sit warm for a long time before anyone opens it and notices. That gap between "looks fine" and "is fine" is where the loss lives.

What a fridge monitoring system actually does

A wireless sensor sits in each fridge or freezer and reports its temperature to a dashboard. It raises an alert the moment a reading crosses the threshold you set, or the moment a door is left open past a grace period. Every reading is logged, so alongside the live warning you build a continuous, timestamped record without anyone touching a clipboard.

Two things make it work in a real kitchen. It has to ignore the normal cycle: fridges and freezers defrost and a reading spikes then settles, so a sensible setup uses a threshold with a short delay plus a trend rule, or staff learn to ignore the alarm. And the alert has to reach whoever is on that night by a channel they will see, SMS, email or a call, after hours included, and keep working in a blackout on battery and a cellular link rather than the shop wifi that dies with the power.

What normal looks like, during service and overnight

A fridge trace has two modes. Through service the door swings constantly, the air inside jumps with every opening, and the graph turns into a sawtooth: up with the door, back down within minutes as the compressor catches up. That bounce is mostly air. The food, sitting in mass, warms far slower, so a unit that recovers quickly after each opening is healthy even when its worst reading looks bad.

Overnight is the opposite: doors shut, no traffic, and the trace should be a flat line inside the safe band with a small regular bump where the defrost runs. That flat line is the baseline worth knowing for every unit you own. A fridge that held 3°C at 4am all winter and now holds 4.5°C is telling you something weeks before it fails.

Display fridges are the hard case. Glass doors, lights, warm room air and stock stacked past the load line all work against them through trade, so judge a display unit by its overnight line rather than its 1pm reading. A storage fridge out the back has no such excuse: if it moves much at all, look at it.

The silent losses a cafe or restaurant actually hits

None of these announce themselves. A door not sealed after a delivery, a tiring compressor losing ground over weeks, a power cut over a public holiday, an iced-up evaporator choking the airflow while the unit still hums along sounding normal. They all creep, which is why watching the trend beats watching a single number. If you have already had the near miss, our guide to catching a failing fridge or coolroom before stock spoils covers the warning signs in detail.

Door ajar, defrost cycle or a failing compressor

Three different problems make a fridge read warm, and the shape of the trace tells them apart.

A defrost cycle is a short, sharp spike at the same times every day. The reading climbs a few degrees for twenty or thirty minutes, then drops straight back to where it sat. It repeats on a schedule, the recovery is immediate, and an alert rule with a short delay ignores it entirely.

A door left ajar is a steady climb from one identifiable moment, usually straight after a delivery, a rush or a close, and it keeps climbing until someone shuts the door. Recovery is quick once they do, because the machine was never sick. A door alert turns this from a morning-prep discovery into a two-minute fix the same night.

A failing compressor is the slow one. The unit still runs and still sounds right, but each cycle claws back a little less: the peaks sit higher, the recoveries stretch longer, and the overnight baseline creeps up across days or weeks. That drift is easy to miss on the front readout and unmistakable on a trend line, which is exactly the failure a trend alert exists to catch.

What to do when a fridge alert fires

The alert worth paying for is the one that lands at 2am on the Saturday of a long weekend. That is the classic write-off: the compressor gives out after Friday close, the fridge is full because the weekend order arrived that afternoon, and nobody is due in until Tuesday. Unwatched, the meat, dairy and prep sit in the danger zone for three days, the lot goes in the bin, and there is no record of when it started. Watched, it is one SMS and a short drive.

When the message lands, the order of operations is short:

• Acknowledge the alert so it stops escalating, then open the trace before you get in the car: a spike already falling is a defrost or a door someone has since shut, a steady climb is the door or the power, a slow grind is the machine.
• At the unit, buy time. Keep the door shut, and if the unit is clearly dead move the stock into another watched fridge or the coolroom. Cold leaves a closed, full fridge slowly; every opening spends some of it.
• Let the log decide what to keep. The record shows how warm each unit got and for exactly how long. That is the difference between binning everything on principle and keeping what provably stayed at 5°C or below, because the 2-hour/4-hour rule runs on hours above 5°C and the log is the only honest count of them.

Power failures are their own case. The sensors keep logging on battery and the alert still reaches you over the cellular link, which also covers planned outages, like a meter exchange that cuts power to the shop mid-morning.

Logs, and the council inspection

Continuous, timestamped logs are exactly the audit-ready evidence an authorised officer wants to see, and they are far stronger than a hand-written sheet that gets skipped on a busy day or back-filled at close. An officer can tell the difference. The honest comparison of the two, and why automatic wins, is in manual temperature logs versus automatic. Be clear on what monitoring does: it gives you the records and the alerts, the compliance obligation stays with you, and we do not sell a certification.

One system for the fridges, freezers and coolroom

Every fridge, freezer, prep unit and walk-in coolroom can sit on the one dashboard, each with its own safe range and its own escalation, so the whole kitchen is watched the same way and there is one record to show. Freezers behave differently and are covered in freezer temperature monitoring for a food business; for a walk-in cool room specifically our spoke Coolroom Alarm is purpose-built. And if a fridge keeps tripping or struggling, it is worth checking whether it needs its own circuit. For the full overview, see the temperature monitoring guide.

Running two or three sites is where monitoring stops being a convenience. Every unit across every site sits in the one rolled-up view, so the cafe you are not standing in is watched as closely as the one you are. Alerts go first to whoever runs that site and escalate if nobody acknowledges. Each site's record stands on its own when an officer visits, and because every fridge is logged the same way, the unit running warmer than its siblings across the fleet identifies itself.

Common questions