I made a mistake in my soapmaking this past Saturday that I’m really looking forward to seeing how it turns out.

Bucket o’ mistake-soap.

Let me provide a bit of background. When I’m setting out to make several batches of SunSoap, I do a fair bit of prep work. I mix up a giant vat of the relevant oils and heat them together, and measure out lye in the appropriate quantities to make the assorted batch sizes to fit my various molds. Then for each individual batch I weigh out the right amount of the mixed oils, add the relevant lye allotment, and color/fragrance as desired.

Well, on Saturday I got a bit too caught up in what I was doing and measured out too much oil for one batch – basically, I measured out enough oil for a five-pound batch despite using a four-pound mold. This wouldn’t have been a significant error if I’d also grabbed a five-pound allotment of lye; I’d’ve had too much soap for the mold, but I could have put the extra somewhere else. But no; I used the four-pound allotment of lye, and didn’t realize the mistake until the soap was colored, fragranced, and poured into the mold. Which means this batch of soap is now about 30% superfatted instead of the desired 3% or so.

What is superfatting? It’s a technique used by many artisan soapmakers to provide an extra moisturizing bar of soap by including some excess in the oil phase which will remain unreacted with the lye and remain in the finished soap. Often, carefully-selected oils are added very late in the soapmaking process in an attempt to make these oils more likely to be among those unreacted with the lye and present a particular profile in the moisturizing aspect. I’m not 100% convinced that doing this actually does have any significant effect on which oils remain behind in the finished soap, but this doesn’t stop me from adding the avocado oil late in my soaping process. After all, it can’t hurt, right?

The technique of superfatting very likely arose not primarily as a means of making soap more moisturizing per se, and more as a way of allowing for inaccuracies of early soapmaking methods and ensuring that no lye remained unreacted in the finished soap. Without accurate scales – or, even earlier in soapmaking history, without lye of known strength – it was difficult to know one had added the correct amount of lye, and if it is virtually certain there will be unreacted ingredients in the finished product, it’s better and safer that they be oil rather than lye. Hence, superfatting. This is rarely a problem with modern methodology, but sufficient other benefits are forthcoming that a modest percentage of superfatting is almost universally used.

It’s not a technique without shortcomings, however. Highly superfatted soap doesn’t lather as well. Also, if too much excess oil is used, it can create large enough deposits in the soap that it can oxidize and create what is known in the trade as the Dreaded Orange Spots. This is not the necessarily kiss of death for soap, but it is rather unsightly, and in extreme cases the afflicted soap can actually go rancid. Yuck! So I try to keep my superfatting percentages below 5%, as a compromise between moisturizing and lather, and to stay well below the DOS threshold.

So what does this mean for my accidental 30% superfatted soap? Well, obviously it won’t be leaving my hands; if ever a soap were likely to go off in interesting ways, this would be it, and I don’t want that to happen out in the wild. But I’m fascinated to watch how it behaves, once it cures a bit. Will it be too soft to hold a bar shape? Will it lather at all, or just sort of sit there greasily? Will it develop Dreaded Orange Spots within the month? I have no idea! But despite dumping the batch out of the mold and replacing it there with a properly-made batch, I kept this around in a plastic box to let it progress as it will. For Science!, don’tyaknow. If I learn anything remotely interesting, I’ll let you know.


About Amy Young

Founder of Foam on the Range soaps. View all posts by Amy Young

5 responses to “Whoops!

  • xaminmo

    What ever happened to this batch? Did it sweat out some of the extra oil? Did you end up rebatching it with extra lye?

    I recently mismeasured the other direction, and decided to rebatch with extra oil. That worked, but I mistakenly added extra water, and now it’s more like pump soap, even after extensive drying. So much EO, that I’ll probably actually put it into pump bottles instead of trashing it.

    • Amy Young

      I left it for several weeks, then tried rebatching some of it straight and some of it with extra lye, more out of curiosity than anything (it was multicolored/swirled soap, so once all glorped together it was a REALLY unappealing brown). It didn’t really work, though, alas, and I ended up just trashing it.

      Last time I mismeasured (slightly) in the other direction, I cut up the soap really, really small and embedded the chunks in an extra-superfatted batch of the same scent. It worked out much better than I would have expected, though I let it cure about three months to be sure it all equalized.

      I hope your pump-soap-solution turns out to work! I’ve never had much luck turning bar soap liquid (on purpose, anyway), myself; it gets all icky after a while.

      • xaminmo

        Yah, my soft soap was KOH, and my crumbly soap was NaOH.

        The hard soap fixed up fine, but I thought “Oh, mixing these will harden up the KOH soap!” HAH.

        I spread a half inch in a jelly-roll pan and baked it at 170 for 4 hours. It volcanoed when I wasn’t looking. WHEE! Now, the soap is just foamy and creamy, with some… well, not wet, but definitely not hard spots.

        I put it into a deep freezer, and even at zero F, it was like soft butter.

        It smells great, lathers great, and is a beautiful, creamy-orange color (paprika, turmeric, zinc oxide, sweet orange, tea tree, almond meal).

        I might also try using a small amount as a thin swirl in a full sized batch, but i think that might just make the bar split along the swirls.

        Other experiments include salt, and candellila wax, but I’m 99% sure it will just end up in a non-foaming pump.

      • Amy Young

        Ooh, yeah, a KOH soap never will harden beyond sort of paste, barring adding enough salt that it turns into an NaOH soap when no one’s looking. Fun with chemistry!

        Mixing the two gets you cream soap, though, which is pretty awesome in its own right. One thing I love about making soap: You usually end up with something nifty, even if it’s not what you were aiming for in the first place!

      • xaminmo

        Science! I looked up everything I could find for hardening soap.
        * I had no sodium lactate, nor lactic acid, but this looks like as much a Sodium donor as anything else.
        * Ethanol had no real effect other than making the soap translucent
        * Sugar had a very minor hardening effect.
        * Salt was awesome. Add in salt, mix, cook 30 mins, mix again, and it hardens up pretty substantially. Like you said, replacing the Kalium with Natrium.

        Unfortunately, I ran out of salt. I have 6.48 mols of potassium, and about 2.5 mols of sodium in there including salt.

        The test blob hardened up TOO much, so I’ll want to be a little under stoichiometric conversion to keep it from being too hard to mold. Still, time to hit up the store.

        I’m wondering what the KCl in there will do to the lather, or if it will even be noticeable with the carbonate in there too.

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