Signs Your Kitchen Extract System Needs Cleaning

In the daily pressures of running a commercial kitchen, it can be easy to overlook the state of your extract system until a problem becomes obvious. But a well-maintained system should not wait until visible problems appear — and in some cases, the signs of a system that needs attention are not immediately obvious to kitchen staff.

Here are the key indicators that your commercial kitchen extract system may be due — or overdue — for professional cleaning.

1. Grease Visible Around Canopy Edges and Surfaces

The most visible sign is grease deposits visible on the surfaces of the canopy body itself — around the filter frame, along the internal surfaces of the hood, and particularly on the outer edges and undersides of the canopy that are visible during service.

While some surface grease is inevitable in a busy kitchen, heavy accumulation, grease drips or build-up that cannot be removed by routine in-house cleaning is a clear signal that professional attention is needed.

2. Saturated or Heavily Discoloured Baffle Filters

Baffle filters are designed to capture grease before it enters the ductwork. In a busy kitchen, they may need washing by kitchen staff weekly or more frequently. However, over time, baked-on grease accumulates that in-house washing cannot fully remove.

Filters that appear heavily discoloured — brown or dark rather than their original silver/aluminium colour — even after washing, or that feel tacky with grease even when apparently clean, are overdue for professional deep cleaning or replacement.

3. Reduced Airflow from the Extract System

If your kitchen staff notice that the extract system is less effective — that cooking smells are lingering longer than they used to, or that the system doesn't appear to be drawing as strongly — this can indicate grease build-up within the ductwork restricting airflow.

This reduced performance has practical consequences beyond comfort: a less effective extract system means cooking vapour, heat and steam circulate longer in the kitchen, affecting working conditions and potentially contributing to condensation and hygiene issues.

4. Unusual Smells from the Extract System

A strong or unusual smell coming from the extract system itself — particularly a rancid or burning grease smell — can indicate significant grease accumulation within the ductwork that is now breaking down or becoming rancid.

This can also indicate that grease deposits are being heated to temperatures where they are starting to smoke or oxidise within the duct — a concerning sign from a fire risk perspective.

5. Grease Residue or Staining Around External Discharge Points

If grease residue is visible on the external wall or rooftop around your kitchen extract discharge point — staining, drips or a general greasy coating around the discharge grille — this suggests grease is travelling the full length of the duct run and escaping via the discharge point.

This indicates the system has not been cleaned recently enough for the volume of cooking, and grease levels within the ductwork may be significant.

6. Your Last Clean Was More Than the Recommended Interval Ago

One of the clearest signals is simply the calendar. If it has been longer than the TR19-recommended interval for your kitchen type since the last professional clean — quarterly for heavy use, six-monthly for moderate use, annual for light use — then you are overdue regardless of whether visible signs are obvious.

Grease accumulation is happening inside ductwork where you cannot see it. Do not wait for visible external signs; follow the recommended schedule for your kitchen's use intensity.

7. Kitchen Fires or Near-Miss Incidents

If your kitchen has experienced a small fire, a flash fire at the canopy, or a near-miss incident involving heat or flame near the extraction system, this should prompt an immediate professional inspection and clean before further service continues.

Even if a fire appears minor and is quickly extinguished, grease deposits within the ductwork may have been heated to close to ignition temperature. An inspection is essential.

8. New Insurance Policy or Renewal Requirement

If your insurer or broker has specifically requested evidence of extract cleaning documentation — whether at renewal, as a mid-term policy condition, or following a change in cover — this is a clear and practical trigger for arranging a professional clean with proper post-clean documentation.

9. Change of Ownership or Management

When a commercial kitchen changes hands — whether through a business sale, lease transfer, or change of management company — the incoming operator should arrange a full inspection and professional clean as part of their due diligence, regardless of when the previous clean took place.

This ensures the new operator has current documentation for their own insurance and compliance records, and gives them a clear picture of the current system condition.

10. New or Significantly Changed Kitchen Equipment

If your kitchen has added new cooking equipment — particularly additional fryers, a new chargrill, a solid fuel oven or other high-heat, high-grease cooking equipment — your extract system loading has changed. The previous cleaning frequency may no longer be appropriate, and an assessment by a specialist contractor is worth arranging.

Acting on the Signs

If you recognise any of the above signs in your Pembrokeshire commercial kitchen, the practical next step is to arrange a professional extract system assessment and clean. We connect food businesses across Pembrokeshire and West Wales with specialist providers who can assess your system condition, carry out the required cleaning, and produce the documentation your business needs.

Contact us to arrange a quote. We cover all of Pembrokeshire, from Haverfordwest and Milford Haven to Tenby, Narberth, Fishguard and St Davids.