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Kitchen deep cleaning - warewashing
A commercial dishwasher or glasswasher does more than a domestic one: as well as cleaning, it sanitises - killing bacteria with a hot final rinse - so the ware comes out not just clean but hygienically safe. That depends on the machine reaching the right temperatures, which depends on it being maintained. Here is how commercial dishwashers and glasswashers work, and the maintenance they need.
The short answer
A commercial dishwasher or glasswasher does two things: it cleans the ware (dishes, glasses, utensils) and it sanitises it - and the sanitising is what distinguishes a commercial machine from a domestic one. The typical cycle has a wash and a rinse. The wash cleans the ware, using detergent and hot water at around 55-60C to remove the food soiling and grease. The final rinse then sanitises, using water at a higher temperature - about 82C or above (commonly 82-88C) - which kills bacteria by heat (thermal sanitising), so the ware comes out not just clean but hygienically safe. So a commercial dishwasher delivers ware that is both cleaned (by the wash) and sanitised (by the hot rinse), which is why commercial kitchens use them: they achieve the hygienic standard that food-contact ware needs, killing the bacteria that a clean-only wash would leave. (An alternative is chemical sanitising, using a sanitising chemical in the rinse rather than high heat - used for glasswashers, or where hot water is limited - which achieves the sanitising by chemical means instead of temperature.) The crucial point is that the sanitising depends on the machine actually reaching the right temperature (or delivering the sanitising chemical) - and that depends on the machine being maintained. If the machine cannot reach the sanitising rinse temperature, it cleans but does not sanitise, so the ware is not hygienically safe - a food-safety failure that can go unnoticed because the ware looks clean. The main threat to the machine reaching temperature is scale: in hard-water areas, limescale builds up in the machine (on the heating elements and water paths) and impairs its performance, potentially stopping it reaching the sanitising temperature - so regular descaling is essential maintenance. And the machine itself needs cleaning (of food debris, grease and filters) to work properly and hygienically. So commercial dishwashers and glasswashers clean and sanitise the ware, using a hot wash and a hotter sanitising rinse (or chemical sanitising), and they depend on being maintained - descaled and cleaned - to keep reaching the sanitising temperature and delivering hygienically safe ware. The maintenance is essential, because a machine that cannot sanitise is failing at its main job even if the ware looks clean.
Key points
Clean and sanitise
The key thing about a commercial dishwasher or glasswasher is that it does more than clean - it sanitises, which is what distinguishes it from a domestic machine and makes it suitable for a commercial kitchen. Cleaning removes the visible soiling - the food debris, grease and dirt - from the ware, so it looks clean. Sanitising goes further: it reduces the bacteria on the ware to a safe level, so the ware is not just clean but hygienically safe to use for food. A domestic dishwasher primarily cleans; a commercial one cleans and sanitises, because in a commercial kitchen the ware (plates, glasses, utensils) is food-contact and used by many people, so it has to be hygienically safe, not just visually clean. So the commercial machine's sanitising is essential to its job - delivering ware that is safe as well as clean.
This matters because clean is not the same as hygienically safe. Ware that has been washed clean of visible soiling can still carry bacteria - the cleaning removes the dirt but not necessarily the bacteria - so cleaning alone does not make the ware hygienically safe. Sanitising is what deals with the bacteria, reducing them to a safe level, so that the ware is safe to serve food on or drink from. In a commercial kitchen, this hygienic safety is required, because the ware is used repeatedly by many people and must not transfer bacteria - so the sanitising the commercial machine provides is not a luxury but a necessity. This is why a commercial dishwasher is not just a bigger domestic one: its defining feature is the sanitising, which achieves the hygienic standard commercial ware needs. So understanding that a commercial dishwasher cleans and sanitises - and that the sanitising is the essential part that makes the ware hygienically safe - is the key to understanding how it works and why its maintenance matters. The sections below cover how the sanitising is achieved (the temperatures) and why maintaining the machine is essential to it (reaching those temperatures).
How it sanitises
A commercial dishwasher sanitises through temperature, in a cycle of a wash and a hotter final rinse. The wash cleans the ware: it uses detergent and hot water at around 55-60C to remove the food soiling and grease from the ware. This wash gets the ware clean, but the wash temperature alone is not high enough to reliably sanitise - so the sanitising is done by the final rinse. The final rinse uses water at a higher temperature - about 82C or above (commonly in the 82-88C range) - and it is this hot rinse that sanitises the ware, killing the bacteria by heat. This is thermal sanitising: the high temperature of the final rinse is what kills the bacteria, reducing them to a safe level, so the ware comes out sanitised. So the cycle is: wash to clean (around 55-60C), then a hot rinse to sanitise (around 82C or above) - the hot rinse being the sanitising step.
So the sanitising depends on the final rinse reaching the right temperature - about 82C or above - because that is what kills the bacteria. If the rinse reaches that temperature, the ware is sanitised; if it does not, the ware is cleaned but not properly sanitised, because the heat needed to kill the bacteria was not reached. So the temperature of the final rinse is critical to the sanitising, which is why it matters that the machine actually reaches it. There is an alternative to thermal sanitising: chemical sanitising, which uses a sanitising chemical in the rinse rather than high heat to kill the bacteria - used for glasswashers (glasses are often washed at lower temperatures) or where the hot water supply is limited. Chemical sanitising achieves the sanitising by chemical means instead of temperature, so a machine using it sanitises via the chemical rather than the heat. But whether by heat or chemical, the sanitising is a distinct step beyond cleaning, and it depends on the machine delivering it properly - the right rinse temperature for thermal sanitising, or the right chemical for chemical sanitising. So how a commercial dishwasher sanitises is by the hot final rinse (or the sanitising chemical), and the sanitising depends on that being delivered correctly - which is where maintenance comes in.
Why maintenance matters
The crucial point is that the sanitising depends on the machine actually reaching the sanitising temperature (or delivering the sanitising chemical) - and that depends on the machine being maintained. If a machine that should sanitise thermally cannot reach the sanitising rinse temperature - because something is impairing its heating or performance - then it cleans but does not sanitise, so the ware is not hygienically safe. This is a food-safety failure, and a dangerous one because it can go unnoticed: the ware looks clean (the washing still removes the visible soiling), so nobody realises the sanitising has failed - the ware comes out looking fine while carrying bacteria the failed sanitising did not kill. So a machine that cannot reach its sanitising temperature is failing at its main job (delivering hygienically safe ware) while appearing to work, which is exactly why maintaining it matters - the failure is hidden behind clean-looking ware.
The main threat to a machine reaching its sanitising temperature is scale. In hard-water areas, limescale builds up in the machine - on the heating elements and in the water paths - and this impairs its performance: scale on the heating elements reduces their efficiency, so the machine may struggle to heat the water to the sanitising temperature, and scale in the water paths impairs the flow. So limescale build-up can stop the machine reaching the sanitising temperature, causing exactly the hidden sanitising failure described - which is why regular descaling is essential maintenance, especially in hard-water areas. Descaling removes the limescale, restoring the machine's ability to heat the water and reach the sanitising temperature. And the machine also needs cleaning to work properly and hygienically: food debris and grease accumulate in the machine, and the filters need cleaning, so a machine that is not cleaned can become clogged and less effective, and unhygienic in itself. So maintaining a commercial dishwasher means both descaling it (to keep it reaching the sanitising temperature) and cleaning it (to keep it working and hygienic) - both essential to the machine continuing to clean and sanitise properly. Neglect the maintenance and the machine can fail to sanitise (from scale) or become ineffective and unhygienic (from dirt), undermining the hygienic ware it exists to deliver. So the maintenance - descaling and cleaning - is essential, because a machine that cannot sanitise is failing even when the ware looks clean.
Keeping it working
So keeping a commercial dishwasher or glasswasher working means maintaining it - descaling and cleaning it - and, ideally, checking that it is reaching its sanitising temperature. Descaling, especially in hard-water areas, keeps the machine able to reach the sanitising temperature by removing the limescale that would impair its heating; it should be done regularly, at a frequency matched to the water hardness and the machine's use. Cleaning the machine - removing food debris and grease, cleaning the filters and the interior - keeps it working effectively and hygienically, so it does not become clogged, ineffective, or a source of contamination itself. And checking the sanitising temperature (that the final rinse is reaching about 82C or above, for thermal sanitising) confirms the machine is actually sanitising - catching the hidden failure that scale or a fault could cause. So the maintenance is descaling, cleaning, and checking - keeping the machine reaching temperature, working effectively, and confirmed to be sanitising.
This maintenance matters because the machine's job - delivering hygienically safe ware - depends on it, and the failure of that job can be hidden. A commercial dishwasher that is descaled, cleaned and reaching its sanitising temperature delivers clean, sanitised, hygienically safe ware; one that is neglected can fail to sanitise (from scale) while still looking like it works, delivering clean-looking but unsafe ware. So the maintenance is not optional upkeep but essential to the machine doing its food-safety job. This connects to the broader care of the kitchen's equipment: the dishwasher, like other equipment, has to be maintained and kept clean to work properly and hygienically, and its particular maintenance (descaling for the sanitising, cleaning for the function and hygiene) is important because its job is a food-safety one. So commercial dishwashers and glasswashers clean and sanitise the ware, achieving the hygienic standard commercial ware needs, and they depend on being maintained - descaled, cleaned and checked - to keep doing so. The maintenance keeps the machine reaching its sanitising temperature and working properly, so it delivers hygienically safe ware rather than clean-looking but unsafe ware. Keeping the machine maintained is keeping it doing its essential job.
The takeaway
A commercial dishwasher or glasswasher does more than a domestic one: it cleans and sanitises the ware, so it comes out not just clean but hygienically safe - which is essential, because commercial ware is food-contact and used by many people. It works in a cycle: a wash at around 55-60C to clean the ware of food soiling and grease, then a hot final rinse at about 82C or above to sanitise it, killing the bacteria by heat (thermal sanitising). The hot rinse is the sanitising step, and the sanitising depends on the rinse reaching that temperature. (An alternative is chemical sanitising, using a sanitising chemical rather than high heat, used for glasswashers or where hot water is limited.) The crucial point is that the sanitising depends on the machine actually reaching the sanitising temperature - and that depends on maintenance.
If the machine cannot reach the sanitising temperature, it cleans but does not sanitise, so the ware is not hygienically safe - a food-safety failure that can go unnoticed because the ware still looks clean. The main threat is scale: in hard-water areas, limescale builds up and impairs the machine, potentially stopping it reaching the sanitising temperature - so regular descaling is essential. And the machine needs cleaning (of food debris, grease and filters) to work properly and hygienically. So maintaining a commercial dishwasher means descaling it (to keep it reaching the sanitising temperature), cleaning it (to keep it working and hygienic), and ideally checking it is reaching temperature (to confirm it is sanitising). The maintenance is essential, because a machine that cannot sanitise is failing at its main job even when the ware looks clean. So commercial dishwashers clean and sanitise, and they depend on being maintained to keep delivering hygienically safe ware - the descaling and cleaning being essential to the sanitising that is their whole point.
Questions
It sanitises as well as cleans. Cleaning removes the visible soiling (food debris, grease, dirt) so the ware looks clean; sanitising reduces the bacteria on the ware to a safe level, so it is not just clean but hygienically safe to use for food. A domestic dishwasher primarily cleans; a commercial one cleans and sanitises, because in a commercial kitchen the ware (plates, glasses, utensils) is food-contact and used by many people, so it has to be hygienically safe, not just visually clean. This is essential because clean is not the same as hygienically safe - washed ware can still carry bacteria, which the sanitising deals with. So the commercial machine's defining feature is the sanitising, which achieves the hygienic standard commercial ware needs. It is not just a bigger domestic machine; its sanitising is what makes it suitable for commercial food use.
Typically it washes at around 55-60C and then does a final rinse at about 82C or above (commonly 82-88C). The wash, at around 55-60C with detergent, cleans the ware of food soiling and grease. The final rinse, at about 82C or above, is the sanitising step - the high temperature kills the bacteria by heat (thermal sanitising), so the ware comes out sanitised as well as clean. So the wash temperature cleans and the higher rinse temperature sanitises. The sanitising depends on the final rinse reaching about 82C or above, because that is the temperature that kills the bacteria - if the rinse does not reach it, the ware is cleaned but not properly sanitised. (Glasswashers and machines where hot water is limited may use chemical sanitising instead, with a sanitising chemical in the rinse rather than the high heat.) So the temperatures matter: the wash cleans, and the hot rinse sanitises.
Cleaning removes the visible soiling - the food debris, grease and dirt - so the ware looks clean. Sanitising reduces the bacteria on the ware to a safe level, so it is hygienically safe to use for food. They are different: ware can be cleaned of visible soiling while still carrying bacteria, because the cleaning removes the dirt but not necessarily the bacteria - so cleaning alone does not make the ware hygienically safe. Sanitising is what deals with the bacteria, making the ware safe to serve food on or drink from. In a commercial kitchen, both are needed: the ware must be clean (free of soiling) and sanitised (safe from bacteria). A commercial dishwasher does both - cleaning with the wash and sanitising with the hot rinse (or a sanitising chemical) - which is why it delivers ware that is not just clean but hygienically safe. Clean is necessary but not sufficient; sanitising completes the job.
Because limescale build-up can stop the machine reaching its sanitising temperature, causing a hidden food-safety failure. In hard-water areas, limescale builds up in the machine - on the heating elements and in the water paths - and impairs its performance: scale on the heating elements reduces their efficiency, so the machine may struggle to heat the water to the sanitising temperature, and scale in the water paths impairs the flow. So scale can stop the machine reaching the sanitising temperature, meaning it cleans but does not sanitise - a food-safety failure that can go unnoticed because the ware still looks clean. Regular descaling removes the limescale, restoring the machine's ability to heat the water and reach the sanitising temperature. So descaling, especially in hard-water areas, is essential maintenance - it keeps the machine able to sanitise, which is its main job. Without it, scale can silently defeat the sanitising while the ware looks fine.
Because the sanitising can fail while the cleaning still works, so the ware looks clean even though it is not sanitised. If the machine cannot reach its sanitising temperature - because of scale or a fault - it still washes the ware clean of visible soiling, so the ware comes out looking fine, but it carries bacteria the failed sanitising did not kill. Nobody realises the sanitising has failed, because the visible result (clean-looking ware) is unchanged - the failure is hidden behind the clean appearance. This is why a sanitising failure is dangerous: it delivers clean-looking but unsafe ware without any obvious sign. So the failure has to be caught by maintenance and checking: descaling to prevent the scale that causes it, and checking the sanitising temperature (that the final rinse reaches about 82C or above) to confirm the machine is actually sanitising. Relying on the ware looking clean is not enough, because a machine that has stopped sanitising still produces clean-looking ware.
Descaling, cleaning, and ideally checking its sanitising temperature. Descaling - especially in hard-water areas - removes the limescale that would impair the machine's heating and stop it reaching the sanitising temperature, and should be done regularly at a frequency matched to the water hardness and use. Cleaning the machine - removing food debris and grease, cleaning the filters and interior - keeps it working effectively and hygienically, so it does not become clogged, ineffective, or a source of contamination itself. And checking the sanitising temperature (that the final rinse reaches about 82C or above, for thermal sanitising) confirms the machine is actually sanitising, catching the hidden failure that scale or a fault could cause. So the maintenance keeps the machine reaching temperature (descaling), working and hygienic (cleaning), and confirmed to be sanitising (checking) - all essential, because the machine's food-safety job of delivering hygienically safe ware depends on it, and the failure of that job can be hidden behind clean-looking ware.
A commercial dishwasher needs descaling and cleaning to keep sanitising - and it is one of the food-contact machines our kitchen deep cleaning addresses, alongside the surfaces and equipment. Ask us about a deep clean.
