Aftershave for the gentleman engineer. I promise this won’t become a beauty blog, but all I could find about making this were some very unspecific forum posts and bad science… and here we are, spreading better information one post at a time… ;D)

I’ve been meaning to get myself a good aftershave for a while, but something scented wasn’t really doing it for me, so I decided to make my own mentholated witch hazel. The base, witch hazel, is an astringent, which closes pores.

Witch hazel works because of the tannins in it, which are organic phenols that bind to proteins and cause them to fall out of solution. Tannins are responsible for the dry, puckering mouthfeel of  certain wines and chocolate. This microscopic tendency to bind to proteins results in the irritation of skin pores when applied dermally, and therefore ‘closes’ the pores (in quotation marks because pores never actually open and close of their own accord, but only appear to per the vasodilation or constriction of surrounding skin). This results in less visible pores and reduced oil output, especially after the warmth of shaving can lead to especially visible and ‘open’ pores.

I was interested to make something that was also super chilling with menthol, but didn’t want to pay $15 for something I could make myself for half the price). Measurements and specific ratios were few and far between, though, so I wrote this up. While it’s just about the furthest thing possible from what I usually post, hopefully some concrete numbers can help someone else avoid the frustration I did. Note that this is the arctic-blast/freezing-cold/icicles-on-my-face type of cold – use caution and don’t get it in your eyes.

Materials

• 16 fl. oz. witch hazel
  • I used 86% witch hazel/14% alcohol, which seems common – I don’t mind the alcohol, but some do. A lack of alcohol will definitely affect menthol solubility: menthol is soluble in water at 0.46 mg/ml and in alcohol at 100 mg/ml (@25 °C). I got a 16 fl. oz. bottle from Safeway.for $3.50.
• 13 grams pure menthol crystals
  • Pretty trivial to find and cheap on eBay/Amazon – I got 1oz for $5 and free shipping.

A Note on Solubility

I’m no chemist (so this is probably wildly wrong), but as mentioned above, menthol is soluble at >1 g/mL in alcohols, meaning that in our 16 fl. oz. of witch hazel, we have (.14 * 16 fl. oz.) = 2.24 fl. oz. = ~66.24 mL of alcohol, therefore we have (66.24 mL * 1g/mL) = ~66.24g of methanol until the alcohol is saturated. However, due to some unknown reason, there’s no way you can get nearly this much to dissolve in the witch hazel – I would guess it’s due to how the alcohol and hazel mix (I don’t know if it’s a solute/solvent type thing; I can’t find data on the miscibility/solubility of witch hazel – go figure – but it’s probably not a simple mixture, which would affect how powerful he solvent is). YMMV.

Procedure

I heated the witch hazel in an ~ 95°F water bath for about five minutes, and then dumped in the menthol (crystalline shards up to about 5mm long). The mixture was taken out of the bath, agitated for around three minutes, then put back in the bath for about five minutes, before being agitated once more.

At this point, there was visible oil resting on the surface as well as crystals in a sort of slurry. I skimmed the ~1-2 grams of undissolved crystals off the top, disposed of them, and agitated for another minute or so.

Prior to use, I had to gently shake the bottle to dissolve a thin film of crystals on the surface, but it went away fairly quickly.

I’m sure with greater heat and/or a bit more alcohol, you could get a bit more menthol dissolved, but the concentration as-is is plenty strong for me – it’s so cold that it’s nearly unpleasant, but stays on the right side of burning until the sensation fades after about half an hour.

I hope this helps at least one person; this is now my go-to aftershave (and sometimes just when I wake up in the morning – it feels fantastic and wakes you right up) and it’s nice to have a replicatable procedure for making it.