Why Kitchen Hood Cleaning Matters More Than Most People Think
I’ve spent a fair slice of my life standing on stainless floors at two in the morning, peeling back layers of grease that looked older than some of the chefs. I’ve seen hoods so clogged the extractor wheezed like an asthmatic accordion. I’ve also stepped back from a finished job where the steel shone like a mirror, the fan hummed, and the whole kitchen felt lighter. Those moments remind me that a clean hood is more than a tick-box task. It keeps heat down, stops the air from going stale, cuts fire risk, and keeps inspectors calm.
This article shows you how to clean restaurant kitchen hoods and avoid grease buildup from the point of view of someone who has scraped out more ducting than I care to admit. I’ll walk through the system, the chemicals, the tools, the steps, the mistakes, and the signs that tell you trouble is brewing. I won’t sugarcoat anything. A kitchen hood takes a beating every day, and it never lies about the state of the place.
My aim is simple. I want you to know what works, what doesn’t, and how to keep the whole setup running smooth without waiting for a crisis. Let’s get into the nuts and bolts.
Understanding How Kitchen Hoods Actually Work
A hood looks simple from the outside, but the system behind it behaves like its own creature. Once you understand how the parts talk to each other, you’ll clean smarter and faster.
The Hood, the Filters, and the Ductwork
The hood canopy pulls fumes, heat, and vapour off the cookline. Filters catch grease droplets before they reach the ducts. Ducts carry the air to the fan outside. Grease sticks to every section in different ways. The canopy collects thin misty films. Filters deal with thick droplets. Ducts collect the stuff that slips through and hardens into something close to tar. A good clean covers every stage of that chain, or the system clogs again within weeks.
What Grease Vapour Does Inside the System
Grease vapour behaves like smoke with a grudge. It rises fast, hits the steel, cools, and sticks. It forms a soft layer at first. Then heat from the line cooks it twice, and it turns into a tough, waxy crust. Leave it long enough and it becomes carbon that refuses to shift without strong chemicals or heavy scraping. That build-up narrows the airflow, makes the fan struggle, and raises fire risk because one spark can ignite the deposits inside the ducts.
Legal and Safety Standards Every Kitchen Must Meet
Most commercial kitchens fall under fire safety guidance that demands a regular clean of extraction systems. Insurance checks follow the same pattern. A greasy hood can void a claim with no hesitation. Inspectors look for clear evidence that the hood, filters, ducts, and fan have been cleaned to a professional level. Skipping it or guessing the dates puts the whole place at risk.
The Tools, Chemicals, and PPE You Actually Need
I’ve met cleaners who turned up with nothing but a sponge and hope. That never ends well. A proper kit saves time and cuts stress.
Degreasers and Foaming Agents
A hood needs chemicals made for heavy kitchen grease. A foaming agent clings to vertical steel and softens stubborn layers. A high-alkaline degreaser breaks down carbonised deposits. You want products that can cut through years of heat-cured grease without stripping the steel or leaving slippery residue. A weak cleaner leaves a greasy sheen that becomes twice as hard next time.
Scrapers, Brushes, and Steam Machines
Stainless scrapers shave off hardened layers. Nylon brushes give you control on delicate parts. Long-handled brushes reach deep into ducts. A steam machine works wonders on areas where you can’t risk aggressive chemicals. Steam lifts grease from corners and seams where brushes struggle to reach.
Protective Gear and Safety Steps
I never step into a hood job without gloves, goggles, a mask, and non-slip boots. Grease on tile floors turns the place into an ice rink. Eye protection saves you from splash-back when the chemicals hit hot spots. Good ventilation keeps fumes down. A stable ladder and a dry foothold save your back and your pride.
Step-by-Step Cleaning Method Used by Professionals
This is the workflow I use on every restaurant job, whether it’s a café or a large hotel line. A smooth process keeps the chaos under control.
Preparing the Area and Shutting Down Equipment
I cut power to lights and fan units. Hot surfaces cool before the chemicals go near them. I cover appliances with plastic sheeting and tape the edges so nothing drips into the fryers or onto the cookline. A bucket or drip tray sits under the canopy to catch run-off. A tidy start avoids hours of cleanup later.
Removing and Cleaning the Filters
Baffle filters slide out of their tracks with a firm lift. Mesh filters feel lighter but clog faster. I soak both types in a hot degreasing bath. Foam clings to every fin. After a short dwell, I scrub them with a stiff brush. I check for dents that break the airflow pattern. Filters that rattle or sag go straight in the scrap pile.
Degreasing the Hood Interior
Once the filters are out, the canopy looks honest. I spray foam from the top down. The foam blankets the steel and loosens the greasy film. After the dwell, I scrape off the thick patches and brush the surfaces clean. A rinse with warm water removes residue. A final wipe gives the steel a neat shine. You can hear the difference once the air moves freely across the canopy again.
Working Through the Ducts
Access panels reveal the real story. Grease inside the duct tells you how long the system has been left to its own devices. I brush the ducts with a rotary tool or a long-handled manual brush. A vacuum captures the loosened debris. On tough jobs, I coat the duct walls with foam and let the chemical soften the baked-on layers before brushing again. A clean duct gives you a smooth interior that resists future build-up.
Cleaning and Inspecting the Fan Housing
Fan blades collect thick grease at the tips, which throws them out of balance. I wipe down the blades with warm chemical solution and clean the housing walls. I check the belt tension, bearings, and mounts. A balanced fan keeps the whole system running quiet and steady. A dirty fan screams for help, and you can hear it across the yard.
How To Prevent Grease Buildup Between Deep Cleans
Daily habits make the real difference. A hood can stay workable for months if the team sticks to a simple routine.
Daily and Weekly Maintenance Routines
A quick wipe of the canopy at the end of service stops the thin film from turning into a hard crust. Filters that go through a hot wash once a week last longer and trap more grease. Staff can shake loose debris into a bin before soaking the filters in a sink filled with hot water and light detergent.
Choosing the Right Filters and Knowing When to Replace Them
Good-quality baffle filters hold their shape and maintain steady airflow. Cheap ones bend, rattle, and clog. A bowed filter lets vapour slip through and load the ducts with grease. A filter that feels heavy even after washing has reached its limit.
The Power of Scheduled Deep Cleaning
A fixed schedule stops the system reaching the point where grease turns into carbon. Busy fry lines need more frequent work because vapour builds twice as fast. A quieter kitchen can stretch it out a bit, but every kitchen benefits from consistent intervals. You save money in the long run because the ducts stay easier to clean.
Common Mistakes That Cause Grease Buildup
I’ve watched kitchens fall into the same traps repeatedly. A few small errors cause big headaches.
Relying on Cheap Chemicals That Don’t Break Down Carbon
A mild cleaner spreads the grease instead of breaking it down. The steel looks wet but never truly clean. The next layer sits on top and hardens quicker than before. A strong degreaser might cost more, but it prevents the cycle of half-cleaned surfaces.
Forgetting Hidden Areas
Grease hides in seams, corners, drip channels, and behind light covers. These spots turn into little reservoirs of residue that warm up and smell foul during service. A good clean always checks the spots you can’t see at first glance.
Overlooking the Duct Run’s Midpoints
Long horizontal ducts collect more grease than the areas near the canopy. Those midpoints often go untouched for years. Once clogged, they cut airflow and overheat the fan.
Signs of Trouble and When You Need a Professional
A kitchen gives you clear hints when the extraction is struggling.
Changes in Airflow or Increased Heat on the Line
A slow-moving extractor forces heat back onto the cookline. Staff start sweating more than usual. Pans smoke for longer. The whole kitchen feels heavy.
Heavy Odours That Don’t Clear
A smell that lingers points to grease hiding deep in the ducts. Odours often escape through seams and joints where the pressure increases.
Excessive Dripping or Visible Residue
Drips from the canopy show that vapour is condensing on greasy surfaces. Stains on walls or floors near the duct exit point to serious build-up.
Bringing It All Together for a Safer, Cleaner Kitchen
A clean hood keeps the kitchen steady, cool, and safe. The work might feel rough at times, but nothing beats the feeling of a system that runs smooth, smells fresh, and passes every inspection with ease. I’ve seen kitchens turn chaotic purely because the extractor gave up. I’ve also seen chefs breathe a sigh of relief once the air started moving again.
Look after the hood, and it will look after the whole kitchen.