Commercial dishwasher detergent and rinse aid
13 April 2022 -
How to choose the best
detergent and rinse aid for dishwashers
Professional dishwashers used in public places such as bars, restaurants, canteens or delicatessens have very different requirements to traditional domestic dishwashers, and detergent and rinse aid play a key role in guaranteeing both quality hygiene of the tableware and the proper functioning of the machine itself.
Let’s find out more about these essential components of professional dishwashing.
What is rinse aid and when is it used?
Rinse aid is a liquid made up of approximately 90% water, with the remaining 10% being a mix of alcohol, dyes, citric acid and surface-active substances capable of reducing the surface tension of the water, facilitating the removal and evaporation of water from the crockery. By breaking the surface tension of the water, the droplets are converted into a fine water film that glides off quickly, leaving plates, glasses and cutlery dry.
One of the many properties of rinse aid is that it is hydrophobic. Being water repellent is a great advantage because it prevents stains from forming on the dishware. These stains are composed of minerals that remain attached to surfaces once the water has evaporated. These minerals, such as limescale or chalk, are normally present in water, even in water that is not considered “hard water”, creating constant problems during the drying phase. The presence of stains results in poor washing quality.
Rinse aid is used precisely to eliminate this problem, preventing the formation of limescale residues on the washware. During the last rinse of the dishwasher, rinse aid is added so that the residual water on the dishware before drying, is removed and allowed to run off easily, and once evaporated, does not leave any marks, deposits or halos on the cutlery, plates and glasses.
Detergent for professional dishwashers
The detergent must be liquid and is placed in the dishwasher tank together with water, creating a mixture with a very basic pH. This mixture will be pumped at high pressure through the nozzles of the washing arms, hitting the dishware and cleaning it through mechanical action. The presence of the detergent increases the degreasing, cleaning and sanitising action of the water, guaranteeing a higher quality of wash than with water alone. The presence of detergent also reduces washing times, increasing efficiency and lowering running costs.
A specific detergent for professional dishwashers should have the following characteristics:
- low foaming power to avoid foam formation
- the ability to break down dirt on the crockery and keep it in suspension
- contain a high concentration of sequestering agents
- promote the removal of scale and be easy to rinse off
- must not contain corrosive or volatile substances
- must contain a low concentration of phosphates
Dishwasher calibration for correct dosing of detergent and rinse aid
• Rinse aid and detergent are dosed via the dosing pump installed on the machine, if available.
• Calibration of the dosing pump must be carried out by the installation technician according to the hardness of the water itself.
• Before proceeding with calibration, fill the feed tubes of the dosing pump with the relevant product.
• Calibration is carried out using the corresponding adjustment screws on the timer (or electromechanical programmer), or directly from the control panel if electronic models are fitted.
• The level of the liquids in the container must be sufficient for draining. • It must never be lowered until it is emptied or topped up with corrosive or impure products.
• NEVER use chlorine- or hypochlorite-based cleaning agents.
• The installation of an automatic peristaltic dosing pump is always recommended.
Detergent and rinse aid dosing
Detergent dosing depends essentially on 3 variables:
- the characteristics of the detergent
- the hardness of the water
- the type of crockery washed (plates, glasses, cutlery, etc.)
| Water hardness (°f) | 0-15 | 15-25 | <25 |
| Indicative dosage (g/l) | 1 | 1,8 | 2,5 |
The rinse aid dosage depends mainly on 2 factors:
- the chemical and physical characteristics of the rinse aid
- the hardness of the water
When using the SISTEMA PROJECT HIGH DRY rinse aid (surfactant composition <5%) the following dosages are indicated: 0.2 ÷ 0.3 grams/litre. If rinse aid with a higher percentage of surfactants is used, the dosage must be reduced.
For example:
a rinse aid with 5÷15% of surfactants should be dosed at 0.05÷0.2 grams/litre.
• Relative density of the SISTEMA PROJECT HIGH WASH detergent: 1.2 kg/litre.
• Relative density of SISTEMA PROJECT HIGH DRY rinse aid : 1.013 kg/litre.
• Indicative consumption of detergent per rinse (glasses): 2.7 l * 0.8 g/l = 2.16 g / 1.2 g/ml = 1.8 ml
• Indicative consumption of detergent per rinse (dishes): 2.7 l * 1.2 g/l = 3.24 g / 1.2 g/ml = 2.7 ml
• Indicative consumption of rinse aid per rinse: 2.7 l * 0.2 g/l = 0.54 g / 1.013 g/ml = 0.533 ml
• Flow rate of detergent dosing pump: 0.7 l/hour = 0.194 ml/second
• Flow rate of rinse aid dosing pump: 0.5 l/hour = 0.139 ml/second
• Detergent injection time (glasses): 1.8 ml / 0.194 ml/second = 9.28 seconds
• Detergent injection time (dishes): 2.7 ml / 0.194 ml/second = 13.92 seconds
• Rinse aid injection time: 0.533 ml / 0.139 ml/second = 3.83 seconds
For a visual check of the amount of product injected, note that:
• 1 ml ≈ 1g ≈ 8 cm of 4×6 mm tube.
Clearly, the above values are only indicative.
There are also specific products for high-performance osmosis water, with medium-hard to very hard water. The high-tech formulation is designed to cope with critical situations such as water up to 100° F.
An osmosis water detergent such as OSMO WASH avoids the formation of any limescale residue in the dishwashing machine, and even removes the limescale deposits already present.
This makes the specific use of descaling agents and machine maintenance operations unnecessary. It also acts effectively against particularly resistant stains, such as coffee, tea, lipstick, etc…
OSMO DRY, on the other hand, is the rinse aid for osmosis water, formulated on an alcohol base to guarantee self-drying power to the rinse aid.
Recommended in the presence of limescale stains, it helps the dishware to dry clean and shine.
Its special formula gives a high de-foaming power even when cold, during rinsing and with temperatures exceeding 80° C. Its presence in the wash bath contributes to the washing action of the detergent.
If silver and gold cutlery has to be washed, there are specific high-performance detergents such as SILVER WASH for medium-hard to very hard water. This is a high-tech detergent, designed to deal with critical situations such as water up to 100° F, which prevents the formation of any limescale residue in the dishwasher, promoting a descaling of the limescale deposits already present.
The rinse aid and detergent supply pipes are recognisable by specific labels, and must be placed directly into the corresponding product tanks. It is very important not to swap the detergent with the rinse aid, as the two dispensers have different functions and have been built to work with each specific product.
Why does foam form in the dishwasher?
When using professional dishwasher detergents and rinse aids in the correct quantities, no foam should form in the wash chamber. Normally, this occurs in the following situations:
- Non-professional detergents and/or rinse aids have been used, with wrong quantities and not suitable for the type of water used: soft, hard or osmosis water.
- the dishes have been pre-washed by hand with classic household detergents, without rinsing them in depth before loading them in the dishwasher.
Why are the glasses still wet at the end of the wash?
There can be several causes:
- rinse aid has run out
- the washing arms are not turning properly
- presence of limescale deposits in the nozzles
- incorrect washing water temperature
How to prevent the tank from blackening or deposits remaining on the bottom?
It is important to use only professional detergent and rinse aid specific for professional and industrial dishwashers, with a low caustic soda content and avoiding the use of bleach.
The right concentration of detergent in the tank ensures that a deposit does not form in the bottom of the tank, and it is therefore necessary to:
- frequently check that there is a sufficient amount of detergent in the tank
- check that the detergent and rinse aid suction pipes are immersed in the relevant liquids
- check that the filter in the drains is clean
- make sure that the suction pipes are not crushed at any point
Sistema Project Italia staff