Later On

A blog written for those whose interests more or less match mine.

Shave Soap Chemistry & the Unnecessary Lubricating Razor Head

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Joshua Chou has an interesting post at Sharpologist:

Understanding why quality wet shave soap and cream provide more protection than their out-of-the-can counterparts requires scratching the surface at the molecular level. Furthermore, the emergence of over-engineered technology in multi-blade cartridge heads was likely a direct contributor to a generation losing the best component of the daily shave: a good lather.


Admittedly, my first safety razor shave was performed with a $20 razor and a cheap can of Barbasol. I was impatient to try out my new toy and had failed to simultaneously order a proper shave soap or cream with my new razor. Introducing a wet shaving neophyte to the “art” with a cheap can of cream was not only underwhelming, it was downright painful.

Needless to say, my first wet shaving experience elicited nicks, cuts and under-the-chin weepers. It was truly a classic example of what not to do. Luckily, I remained undeterred in my quest for a quality single-blade shave and subsequent shaves performed with the right product have improved drastically over my initial foray into the wonderful world of wet shaving. No more canned cream meant no more weepers.

In reality, canned shaving cream is a misnomer. It’s not cream at all. It’s foam. The chemical properties of canned foam “creams” (and I use the term very loosely) vary widely from the high-quality shave soap typically used by wet shaving enthusiasts.

Shave Soap And The Micelle

Soaps are made from a process called saponification wherein a salt (typically a sodium or potassium) is mixed with a fatty acid and reacted along with an alkali like potassium hydroxide or sodium. The resulting molecule includes a longer hydrophobic (water-fearing) fatty acid chain with a hydrophilic (water-loving) head. The longer fatty chain’s hydrophobic and non-polar properties causes adherence to fats. Conversely, the ionic and hydrophilic salt is more prone to adhere to water in mixture.

Because soap includes both unique properties it acts as an emulsification bridge between oil and water, separating them in either bilayer sheets, liposomes or spherical structures called micelles. These bilayer sheets or micelles tend to trap the oils that are attached to dirt, making it a great cleansing agent.

However, when it comes to shaving, a quality soap acts as a great emulsification buffer layer between the blade and the skin. The longer the fatty tail, the thicker the lather.

And, based on the chemistry above, that layer operates best under conditions that include water and oil. That means the complete buffered layer would not be wholly efficacious without your pre-shave oil. You’re already activating the soap with water but skipping the oil step may cause you to be missing some of the emulsifying benefits of the soap.

Lube Over-Engineering

But why on earth did manufacturers opt for canned creams over quality soaps at the same time multi-blade cartridge razors first made their debut? The answer is likely more complex than we might expect.

Believe it or not, the lubrication strip on cartridge razors actually fills at least some of the same face-protection need as a quality shave soap, albeit limited to the real deal. The other half of lubrication need with the multi-blade cartridge shave can typically be completed with some hand soap in the shower or canned cream. However, we can easily surmise several economic incentives at play here.

First, . . .

Continue reading.

Written by Leisureguy

30 August 2018 at 12:05 pm

Posted in Science, Shaving

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