Best Temperature of water for Rinsing Dishes?

[Dr. Courtney]

One should always specify the function that one is optimizing - in dish washing it is usually minimizing stuff other than the dishes left on them (residues and contaminants) while also minimizing human effort and time. By comparison, costs of hot water and other consumables are not a big deal.

Before I was a scholar, I was a dishwasher - I estimate I washed about a million dishes in a variety of commercial and residential systems. How water trumps cold - other factors being equal (but they seldom are). For hand washing, good water pressure and an industrial and convenient sprayer (hanging from well above the sink) are more important than the temperature of the water. Other system elements to minimize handling after dishes are rinsed are also important, as every handling step potentially introduces contaminants.

But neglecting the importance of water temperature assumes that each and every dish has been perfectly washed and only needs to have the soap removed. It ain't so. Depending on the system, between 1 and 10% of dishes come out still dirty. High pressure hot water in a proper sprayer solves that quickly better than cold water in the same system so that fewer dishes have to go back to the start of the dish cleaning process.

But I got to admit, maybe the hard water in New Orleans gives me a different answer than the soft water in Baton Rouge. Maybe Louisiana cuisine (tends to be fatty) has a different answer than other places. The answer with good industrial sinks and sprayers may be different from slow running tap water at home.

 

[Baluncore]

Is the optimum water temperature actually determined by the surfactant chemistry and the rate of reaction required?

Why is the term “soap” used? Soap is mild as it contains hydrated fats and oils. If the surfactant used was chemically more aggressive, such as an hydroxide, then would the product of the washing process not be a “soap”, suspended in the water?

Should the mass of surfactant used be proportional to the surface area of the item being cleaned, the surface area of the food particles, or to the mass of fat and/or oil remaining to be removed. If all have to be satisfied, should the mass of surfactant be proportional to the sum of all the above?

 

[Ackbach]

As there is no agreement, cold uses no water heater energy, better for the environment!

Ah, but if you take a "whole systems approach", and note that it might take more cold water than hot water, and therefore take more pumping power, that might even it out some. Maybe not a lot, but perhaps that should be considered.

 

[rokytnji]

Being the dude that hand washes dishes while my wife handles the cooking. Being that we live in the desert. I hand wash with Dawn dish washing liquid after soaking dishes for a 1/2 hour or more in scalding hot water. Then rinse dishes using the cold water from tap on the sink. Scrubbing everything vigorously.

Drip dry in a basket. No one gets sick. We are grand parents. Food born sickness is life threatening.
I don't over think this kind of stuff.

My Mom taught me how to wash dishes and pots and pans as a kid. I also worked as a dishwasher after finishing my paper route as a kid. So I am semi professional.