Any properly made soap has no lye left. It doesn’t have to be triple-milled.
It’s called saponification. I know that. But French milled is less harsh. A bar of lye soap like Granny used would eat the skin off your hands.
My good friend has made homemade soap with lye and leftover cooking fat collected from friends such as me for 50+ years now, and I promise you, it does not eat the skin off your hands. It’s not hard to make if you follow directions.
French-milled soap is likely milder, but there’s nothing inherently harsh about properly made lye soap.
They sell that at Wegman’s too. I know because I once got hilariously caught up reading their scent names when I was really just trying to put mayonnaise on the grocery list. (What does “Sawtooth” smell like?!)
I’ve made soap. Granny wasn’t so careful.(a generic granny). Her soap needed to be strong and was harsh.
I couldn’t do any testing but I bet you there was trace lye in most homemade soap.
Not the hobby store glycerin melt kind. I’m not sure what that was.
So not your soap, or your granny, but someone’s granny. Got it.
Personally, I want soap that’s a bit harsh. When a soap advertises that it is gentle/detergent free/etc I won’t consider it. I want something that removes dirt and oily stuff from my hands. If it also exfoliates a bit, so much the better.
I made soap as a hobby. If it leaked lye after I made, I threw it out.
My Granny didn’t have no time for such foolishness. She was helping on the farm. A giant pullet farm and small beef herd. A grape orchard.
Feeding 13 kids and keeping my Gramps out of the wine.
She bought her soap at Ernie Dunlops store. (In Kirby, Ark. It’s still there) Mostly soap flakes and Castile soap. Cheapest she could get, I’m sure.
Lye content in finished soap has to do with the ratio of oil/fat to lye in the final product. Hot process soaps react it all and complete the saponification during the processing stage, but cold-process requires an aging period of weeks to months to allow all the lye to react with the oil and fat.
I suspect Granny’s harsh lye soap was a bit scant on the amount of fat that was needed, and this left some lye in the finished soap. This would be fantastic for removing dirt and grease- what didn’t get removed by the soap would be itself saponified by the free lye in the soap. But it’ll be hell on your skin for sure.
There are all sorts of calculators online these days, but I suspect back in the day, it was more rule-of-thumb, and on top of that, was probably using volumetric measurements and vessels of questionable accuracy. So batches probably varied quite a bit.
I noticed some “Dr. Bronner’s Pure-Castile Bar Soap” at the fancy-schmancy organic supermarket, so I bought one. Not super alkaline for a soap (their web site claims 9.8 but I have not measured it myself). Good soap (I mean, it’s soap) but is organic + made with five different oils, so I can recommend it if you can find it cheap. Otherwise keep looking for one of those big-ass bricks (11 oz or 21 oz) of Castile or Marseille soap if you can find a shop that has not succumbed to shrinkflation. A bar of soap lasts for a while, though.