Why does bar soap require cure while liquid doesn't?

[DeeAnna]

I'm no soap chemistry expert, but I think I have a bit of a clue from quite a bit of reading on the matter as well as from simply documenting the changes that my soap goes through over time.

I really don't see why people, regardless of their academic background, refuse to accept that soap is not at its 100% best in only a week or whatever. All a person has to do is just try a long-term experiment and keep an open mind about the results.

The results aren't massaged into a number like the SoapCalc "numbers" -- at least I haven't heard any handcrafted soapers giving ratings for lather, longevity, mildness, etc. In the commercial soap making world, a battery of tests are used to evaluate irritancy, mushing, cracking, lather volume, bar texture, etc., but their results can't be boiled down to just a number or two either.

Ahem. Well. Stepping off my soap box ...

Yes the increase in mildness and increase in lather is in part due to long-term physical changes in the structure of a bar soap. Commercial soap makers can force these changes by extruding, mixing, or milling the soap. Since we handcrafted soapers don't have access to the machinery that accomplishes these processes, we can use time instead to our advantage.

 

[JayJay]

DeeAnna,

If you were to draw a line graph of your observations what would it look like? Would the benefit from cure aggressively increase in the first couple of months? And then more slowly increase over the year? This is what I am picturing in my head.

I use up most of my soaps before they are even six months old. I have managed to save a couple of bars that will reach their first birthday over the next few months. I can't wait to try them!

 

[DeeAnna]

I would agree that the change in the quality of a soap is faster in the first weeks of cure and slows down as time goes on. A freshly cut soap doesn't lather as well and is softer so it is not as long lived compared with the same soap a month or three later.

I can't say much about any change in mildness with time, since most of my recipes are high lard soaps that are generally pretty mild to begin with, but I understand that a decent cure time can improve the mildness of soaps high in "cleansing" fats, such as coconut oil.

Another complicating issue is that different recipes respond differently to a longer cure. For example, my first real-life experience with the benefits of a longer cure was a soap with 90% lard that lathered very poorly at 2 weeks and only a bit better at 5-6 weeks. I was so unimpressed after using a few bars that I put the rest of the bars away in my stash and ignored them. About a year later, I was tidying one day and decided to toss the last of the bars from this recipe. Curiosity got the best of me, so I tried a bar at the sink first and found it lathered dramatically better at 1 year than it did at first. This is not just wishful thinking on my part -- I keep pretty good notes on this and know the difference between what I think is a "below average" lather and one that is above average.

That said, I would never suggest a soaper should keep soap around for a year or more before use. I certainly don't -- most of my soaps are given away, sold (I sell a tiny little bit in a local shop), or used by the family well within a year after I made them. Most of my recipes improve a lot from a 4-6 week cure -- repeated tests of lathering, hardness, and appearance have given me plenty of proof. I cannot understand why some soapers absolutely refuse to learn about something they can easily check for themselves, if they would only take the time.

 

[JayJay]

It doesn't even seem like it would take much time or energy to notice the difference between a 2 day old soap and a two week old soap. I think that sometimes people just get stubborn and don't want to notice things that are inconsistent with their existing theory. But as a scientist, this person should be well aware of the need to gather objective evidence. Oh well.

 

[Susie]

There are three things "most" people do not want to do for themselves:

1. Think and research for themselves. They want their information spoon fed them in sound-bite sized pieces.
2. Work out solutions with a trial-and-error method. They want to do the same thing over and over and get different results.
3. Wait for anything. The whole concept of delayed gratification is completely foreign.

Please note that I put the word "most" in quotations. That means that I know that this does not apply to everyone. However, on most days, I encounter more of these folks than the other kind.

 

[Steve85569]

There are three things "most" people do not want to do for themselves:

1. Think and research for themselves. They want their information spoon fed them in sound-bite sized pieces.
2. Work out solutions with a trial-and-error method. They want to do the same thing over and over and get different results.
3. Wait for anything. The whole concept of delayed gratification is completely foreign.

Please note that I put the word "most" in quotations. That means that I know that this does not apply to everyone. However, on most days, I encounter more of these folks than the other kind.

Yup.
1.) Immediate gratification is almost fast enough.
2.) If I don't like my HP soap as soon as it's cool enough to cut I'll put in additives until I do.
3.) Patience is a virtue "most" people are not willing to wait for.

I am guilty as charged but learning the error of my ways here from all of you.
I do have a lifetime supply of some additives though ( if I live to be 150).:???:

 

[IrishLass]

I'm late to the party here but I wanted to go back to the idea of "mildness" from an extended cure. I'm in an FB group where someone had to beat her chest that she's a chemist and knows that soap can't be made milder after saponification is complete. To me, that ignored what else might be happening to the oils themselves. So, now my question is, does the crystalization of the soap make for a "milder" bar, and if so, how is that mildness judged or calculated? Thanks!

I don't have any specific, technical/numerical, molecular data that I go by, but Dr. Kevin Dunn's book, 'Scientific Soapmaking' has given me some insights that have helped to explain the consistently increased mildness I've always observed with my own soap formulas over time. On page 230 of his book he basically says that as a soap ages/cures, the alkalis in the soap react with the acidic carbon dioxide that is naturally present in the air, which (as Dr. Dunn then goes on to explain) is the reason that aged/cured soap has always been considered to be milder than fresh soap.

Anyone can claim to be a chemist on the interwebs, but Dr. Dunn is the real deal, and he knows a lot about soapmaking- not only from making it, but also from putting the theories to the test in his lab to see if they stack up or are just myths. I would trust him any day over someone on a FB group doling out faulty info while beating their chest about being a chemist, as if that alone is supposed to be the 'proof' that what they are saying is trustworthy and true. :crazy:


IrishLass

 

[gigisiguenza]

I can't speak to the science of "why", I can only speak to the reality of it.

I recently (few months ago) posted a thread about not being able to use any of my own soaps because they were so very drying. So I began playing with recipes to create a much milder bar, with very little CO, etc. During this time, I'm not using my own soap because it's too drying. These are soaps that are anywhere from 6months to barely a month old. And my usage was to wait the four - eight weeks, then test them out. When every batch dried me out and irritated my sensitive skin is when I stopped using them and began researching new recipe formulas.

Skip forward to this past week.

I'm in the middle of a major life shakeup, thanks to irresponsible roommates etc. I'm broke from covering her lack of contributions, and I'm packing what I own to move. In the process I ran out of my solitary bar of the commercial soap I was using. So, drying or not, I grabbed a bar of my own soap. Now, keep in mind, I haven't used any of these for weeks and weeks, and I've only used them when they were just a month or so old.

Now... I'm prepared for the drying and irritation... so imagine my surprise when my soap lathers like a dream, silky creamy lather, smells softly scented and lovely... and not an ounce of dryness or irritation. Not a thing different in the soap, the water, nothing. Just maturity. That's all. Just using the soap at 5 months old versus using it at 6 weeks old.

There are plenty if scientific reasons why letting soap age improves its qualities. But I prefer to think of it as soapy magic. It takes time for the soapy magic to happen, and if you let your soap mature, you go from a bar you can use (it won't harm you) but won't like, to a bar that's absolutely lovely and makes you smile when you use it because you made it

 

[Susie]

I am so glad you like your soap now! I was sort of heartbroken with you when you said that your soap dried your skin!

 

[gigisiguenza]

I am so glad you like your soap now! I was sort of heartbroken with you when you said that your soap dried your skin!

Susie, I'm so glad too for sure. Not all my soaps work for me though. The high CO soaps (>10%) seem to make me dry and itchy. But the ones at 10% seem ok, which is awesome, because it means I can use my own soaps if I keep the CO lower than 15%

 

[sonoransoapnmadness]

Oddly enough, IrishLass, she noted Dunn's book as proof that nothing happens after saponification. Wish I'd been armed then.

Wow to not being able to use more than 10% CO. And boo to crappy roommates. I haven't talked to à lot of other soapers before this forum. My standard recipe is 25% CO. I still find it less drying than commercial bars. Is my rate higher than average?

On the negative end of curing. My 8-week-old chocolate fudge has NO fragrance left. And my test bar of tres leche-both from NG-is scent free as well. Grrrr.

 

[Susie]

Your scents may come back if you either plane them a tiny bit, or wash them a time or two. Scent often evaporates from the outer millimeter or two, but is right under that.