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What are the proper settings (temperature, water pressure, etc.) for my customer's dishmachine?
Every dishmachine used in our industry should have prominently displayed on it a tag or plate from NSF (formerly the National Sanitation Foundation). This tag states the proper wash and rinse temperatures that are approved for use on that machine. Note that some machines can be used as either high-temp or low-temp machine - on these machines the NSF tag will indicate the proper temperature ranges for both set-ups.
Generally speaking, final rinse pressure should run between 15 - 25 psi. Running higher or lower than this often leads to poor rinsing and poor results. The final rinse temperature on a high-temp machine should ideally run between 180-185o F, which is hot enough to properly sanitize the wares but is low enough to allow for proper rinsing and sheeting of the rinse solution.
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Why is there so much foam in my customer's dishmachine?
There are three common causes for excessive foam in a dishmachine.
· Presoak carryover: Most presoaks contain surfactants which will make quite a bit of foam if they find their way into the dishmachine. Check to make sure that presoaked wares are being thoroughly rinsed before sending them to the dishmachine. Also, make sure that the presoak tub isn’t placed so close to the machine that presoak solution is splashing/spilling into the machine – and make sure that used presoak solution isn’t being disposed of by throwing it into the dishmachine.
· Food soils: Certain types of food soil can produce a lot of foam in a dishmachine. Too much foam in a dishmachine is sometimes an indicator that excessive amounts of food soil are building up in the wash solution. This can be remedied by increasing the detergent dose (to better break down the food soil), better prescrapping, or more frequently changing the wash solution.
· Low temperature: Dishmachine products are designed to be non-foaming. In fact, they often contain foam-suppressing components. However, the products are carefully designed to work under the conditions expected to be found in the dishmachine. If the temperature in the dishmachine is lower than that for which the product was designed to be used in this can cause the system to generate foam. This could occur, for example, if a product for a high-temperature dishmachine were used in a low-temp machine or if the wash/rinse temperatures were simply too low.
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How do you get tea and coffee stains out of kitchen wares?
Tea and coffee stains are best removed with bleach. They typically build up when wares are washed in a high-temp machine (without chlorine sanitizer) with a chlorine-free detergent. There is no bleach in this kind of system to decolorize the tea and coffee stains. To fix this problem either soak the wares occasionally in a bleach solution or add a little bleach to the dishmachine - by switching to a chlorine-containing detergent or by adding a small amount of chlorine bleach to the wash solution.
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Do you need a special product for washing aluminum and precious metals (gold and silver) in a dishmachine?
Aluminum wares can be safely washed in a dishmachine by using a metalsafe detergent – one that has been specifically designed for washing soft metals like aluminum. Do not use a regular heavy-duty dishmachine detergent for washing aluminum wares. Precious metals like gold and silver can be safely washed in a dishmachine with a non-chlorinated metalsafe detergent. Chlorine bleach is very harmful to precious metals. For this same reason, it is not recommended to wash precious metals in a low-temp dishmachine. (You could wash precious metals in a low-temp machine only if a proper detergent was used and the chlorine sanitizer was not added to the final rinse – after which the precious metal wares would need to be sanitized in a (quat-based) third-sink sanitizer solution.)
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How do you determine "cost per rack" of the chemicals used in a dishmachine?
This actually isn’t too bad if you don’t mind a little math. For most of these calculations you need to know four numbers:
· the case/unit price of the detergent
· the product net weight per case/unit
· the concentration of product being used in the dishmachine (typically a weight %)
· the gallons of water that the dishmachine uses per each rack of dishes (this amount is specific to each model of dishmachine)
Step 1 – Determine the product cost per ounce by dividing the case price by the weight ounces of product in each case. For example, a case of 4x9 lb. capsules contains 576 ounces of product (36 pounds x 16 ounces per pound). If this case sells for $75, the cost per ounce of detergent is around $0.13.
Step 2 – Determine the weight of water used per rack by multiplying the gallons of water used per rack by 133.28. For example, since a CMA-44H machine uses 0.96 gallons of water per rinse cycle it uses around 130 wt.ozs. of water per rack (0.96 x 133.28).
Step 3 – Determine the weight of product used per rack by multiplying the weight of water used per rack (from Step 2) by the weight percent of the detergent solution. For example, if a detergent is used at a concentration of 0.2% by weight in a CMA-44H machine this means that 0.26 wt.ozs. of detergent is used per rack (130 wt.ozs. of water x 0.002).
Step 4 – Determine cost per rack by multiplying the weight of product used per rack (Step 3) by the product cost per ounce (Step 1). In this set of examples it costs around $0.034 per rack (0.26 wt.ozs. of detergent per rack x $0.13 per ounce of detergent)
Use similar calculations to determine the cost of rinse aid and sanitizer (when applicable). Adding these numbers together gives you the total chemical cost per rack.
Note that you can use similar steps to determine “racks per case” yield. Do this by dividing the net weight of packaged product (in ounces) by the ounces of product used per rack as determined in Steps 2 & 3 above. The set of examples used above (576 wt.ozs. of detergent per case and 0.26 wt.ozs. of detergent per rack) gives a racks-per-case yield of 2215 racks per case (576 / 0.26).
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