Kevin's Blog

Washing the Dishes

Introduction

Ok, why am I writing a blog post about washing the dishes?

I was never taught how to properly wash dishes as a kid. It was a chore that was just forced onto me with very minimal instruction:

“Take this sponge, add some soap and water, and scrub the dishes.” - My mom, probably

I already knew how to wash my hands and body with soap, so why would the dishes be any different? It should just be common sense, right?

And so through my young adult life, I washed the dishes in a very naive way - get soapy water on everything and just scrub really hard until it’s clean! Then all the germs are dead and the plate is considered “clean”.

This resulted in me hating doing the washing dishes, because it felt very inconsistent. Some dishes would take much longer to clean for some reason that I couldn’t understand: starch hardened onto a bowl, food stuck during cooking in a metal pan, or plastic containers that seemingly took multiple washes to get clean. I just accepted that this was just the norm and everybody dealt with this.

The truth is that there’s some nuance in dishwashing, and different food gunk stuck on different plates require different methods, and there was a scientific explanation for all of this.

I’m the kind of person who has a need to understand a subject fully and intuitively, so here’s a comprehensive guide and explanation of dishwashing that I wish I had earlier in my life.

Dishwashing Explained

Abrasion

This is probably the very first thing we do with dishes: get all the debris and food off the plate.

The most straightforward way to do this would be to manually remove debris off the plate using a fork, or using your hands.

But you might quickly realize that the stream of running water while washing dishes can also break off and clear debris.

There might be some gunk that is stuck onto the palte, and for that you’ll use a sponge and some “elbow grease” - manually scrubbing at the dish.

One trick I learned if your sink faucet has the technology: turn on the “jet spray” for even more water pressure. Think of it as a mini pressure washer. This is also very handy for cleaning things with tiny holes, like cheese graters and strainers.

Even More Abrasion

Stuck-on food in a stainless steel metal pan can be particularly hard to clean. Abrasives like kosher salt or baking soda can add granules to increase friction while scrubbing. This is also the same reason why rough scour pads and steel wool is effective at scrubbing stainless steel.

Heat

Heat helps melt saturated fats, like butter, back into a liquid so they’re easier removed.

Heat is also very important for sanitization - killing bacteria.

The easiest source of heat while cleaning is hot water from the sink.

Deglazing and Boiling Pans

Deglazing is a cooking technique for metal pans, particularly stainless steel pans, where the pan is heated very high and water is poured onto it, the water immediately boils and food debris becomes unstuck. A wooden utensil can also be used for some mild abrasion to add some extra removal power.

For cooking purposes, this is done for flavor purposes, but this also cleans the pan. You may often deglaze a pan solely for cleaning purposes.

Soap

A common misconception: soap is not always “anti-bacterial” - it doesn’t straight up kill bacteria.

Instead, it helps trap the organic cells that carry bacteria, and whisk them away.

Liquid dish soap is a very highly concentrated mix of soap and water, but you can be more economical and environmentally friendly by mixing a lot of water with a little bit of soap to clean more with less soap.

Soap is also particularly effective against fats and oils. However, the more oily a dirty dish is, the more soap is needed to clean it. That’s why it’s often recommended to remove as much oil as possible before washing dishes, through something like soaking a paper towel or wiping off congealed fat, before introducing water and soap.

The Long-winded Science of Soap

Emulsions: Soap as an Emulsifier

Here’s a quick biology crash course: fats are one of the three macronutrients (alongside carbohydrates and protein), which humans need to eat to survive.

Here’s a quick chemistry crash course: fat is a nonpolar substance and water is a polar substance. Polar and nonpolar do not mix. So fat and water don’t mix. This is why it’s hard to clean oily plates with just water.

This is also why fat binds onto plastic tupperware, because plastic is made out of (crude) oil, which is also nonpolar, and so fat binds onto plastic and it’s very hard to clean. On the other hand, glass and ceramic don’t have any issues with fat.

But soap helps turn nonpolar substances into polar, and then the substance can be mixed in water. In other words, soap helps oils and fats dissolve in water so they can be cleaned through abrasion.

For a better and more in-depth explanation, google more about emulsifiers.

Surface Tension: Soap as a Surfactant

This is something I never intuitively understood back in science class. Let me try my best to explain this.

Soaps are designed to lower the surface tension of water.

Lower surface tension of water means that the surface of the water is weaker and can be more “relaxed” - helping

Note that hot water also has lower surface tension than cold water.

Honestly, go google an explanation for surfactants.

Conclusion

Let’s do a synthesis summary of what we just learned: the dishwasher is just a machine that does all of the above:

Wow, we’ve come full circle!

I hope this helped.