low-water vs high-water

[MGM]

Ok so I've been using a variety of recipes and not paying all that much attention to water amounts. I decided to do 2 small unscented/uncoloured batches of the same recipe:

Coconut Oil: 20%
Lard: 30%
Olive Oil: 30%
Grapeseed Oil 15%
Castor Oil 5%
​

One used 1.5:1 water and the other used 2.65:1 water. I expected the one with less water to trace faster. It was exactly the opposite! It took 20 min of off-and-on aggressive stick-blending to get the 1.5 water even to light trace. The 2.65 water took longer than the other emulsify, but traced just a minute after that.
What's going on? Is that what's supposed to happen and I've just misunderstood it this whole time??

 

[DeeAnna]

The 1.5:1 water:lye ratio is 40% lye concentration (I think in terms of the concentration not the ratio, so I gotta convert).

You are right -- When the lye concentration is high -- at least 40% -- this can slow the rate of thickening. I don't have a good explanation about why this happens, just that I've experienced it and know others also have. Look for LionPrincess -- she shared a lot about this phenomenon.

I don't think you can absolutely say a high lye concentration will always slow trace, however. But I don't think you can say that about low water concentrations either.

 

[MGM]

Hmmm ok thanks @DeeAnna . I was basing that assumption on this Soap Queen article and a few other things I'd read. Maybe it was just a fluke, but I was working at the highest possible concentration she recommends and she's right, it WAS tough to work with, but only because I almost burned out my SB (and my patience)!
Update 5 hours later....the low-water soaps are softer to the touch than the high-water soaps. Will poke again and update in the morning, but so far, this is all the exact opposite of what I was expecting!

 

[DeeAnna]

The problem with the Soap Queen and her staff is that they don't have the strongest understanding of soap making and soap chemistry. I can think of several of their tutorials where they make claims that are downright wrong. In this case, they are correct ... to a point. And then they're not.

If you start at, say, 28% lye concentration (2.57 water ratio) and increase to, say, 33% (2.03), you may get less working time. In other words, the soap may come to trace somewhat faster, all other things being equal -- stick blending time, batter temperature, recipe, colorants/additives, etc.

But if you compare soap batter made with lye at 28% (2.57) and 33% (2.03) to batter made with a 40% (1.5), you may find the batter at 40% will be markedly slower to trace. That's even more likely to be true if you go from 40% (1.5) to 50% (1.0).

Like I said before, I'm not sure why lower-than-typical water content in the soap batter can slow trace. It may have something to do with less water that's available to participate in the saponification reaction, so the reaction is inhibited. But that's a total guess. All I know is I have encountered this behavior when using high concentrations of NaOH (40% and higher).

It's possible the reason why the soap at 40% is softer is because it didn't get hot enough to gel. Soap made with less water has a higher gel temperature, so it needs to warm up more to change phase.

 

[cmzaha]

The problem with the Soap Queen and her staff is that they don't have the strongest understanding of soap making and soap chemistry. I can think of several of their tutorials where they make claims that are downright wrong. In this case, they are correct ... to a point. And then they're not.

If you start at, say, 28% lye concentration (2.57 water ratio) and increase to, say, 33% (2.03), you may get less working time. In other words, the soap may come to trace somewhat faster, all other things being equal -- stick blending time, batter temperature, recipe, colorants/additives, etc.

But if you compare soap batter made with lye at 28% (2.57) and 33% (2.03) to batter made with a 40% (1.5), you may find the batter at 40% will be markedly slower to trace. That's even more likely to be true if you go from 40% (1.5) to 50% (1.0).

Like I said before, I'm not sure why lower-than-typical water content in the soap batter can slow trace. It may have something to do with less water that's available to participate in the saponification reaction, so the reaction is inhibited. But that's a total guess. All I know is I have encountered this behavior when using high concentrations of NaOH (40% and higher).

It's possible the reason why the soap at 40% is softer is because it didn't get hot enough to gel. Soap made with less water has a higher gel temperature, so it needs to warm up more to change phase.

Do you think the trace difference could happen because higher water content can heat up faster possibly causing the faster trace? Just a thought. I know I have to force all my 33% and higher Lye Concentration soaps to gel.

 

[Steve85569]

https://www.soapmakingforum.com/threads/smf-december-challenge-high-and-low-water-batch.57559/

This was an interesting challenge and I think you'll find the info contained in it interesting. It was for me at the time...
The gelling stuff is also related directly to water content ( besides the fatty acid profile) - less water takes a higher temperature to cause gel while higher water contents can gel on their own ( relatively low temperatures).

 

[Mobjack Bay]

If I’m remembering correctly, there’s a section in Kevin Dunn’s book about some experiments he did to test effect of lye concentration on speed of trace, with results that were inconclusive or inconsistent. I will try to find that section again, or maybe someone else has the book handy. I’ve been inching up the lye concentration for my recipes and I’m not really noticing a difference going from 33% to 37%. I make one type of soap with HW and LW batter and the LW batter sometimes, but not always (?!), traces more slowly than the HW batter.

 

[dibbles]

The challenge @Steve85569 linked is worth reading. One thing I would caution you about with a low water recipe is stick to well behaved FOs and EOs. The naughty ones will be extra naughty in a low water batch. At least in my limited experience.

 

[DeeAnna]

Dunn's experiments I think you have in mind weren't studying "time to trace".

He was looking at the effect of various water contents and starting temperatures of the soap batter and how those variables affected the temperature during saponification. He also recorded whether the soap got hot enough to go through the phase change from solid to gelled soap (aka "neat" soap) and how this phase change also affected the temperatures during saponification.

His results weren't "inconclusive" really, but they certainly did prove you have to keep a number of variables in mind if you want to predict the behavior of soap during saponification. Here are some general observations I've drawn from his study --

Low water soap heats up faster and reaches a higher maximum temperature compared with high water soap, all other things being equal (AOTBE).

Low water soap can have a considerably higher gel temp than high water soap, AOTBE.

High temperature soap heats up faster and reaches a higher maximum temperature compared with lower temp soap, again AOTBE.

Soap that goes into the gel phase saponifies faster when it's in gel than soap that remains in the solid phase.​

When all of these variables are put together -- starting temp, water content, and phase change -- the results can seem inconclusive, because that's a lot of factors to juggle and interpret at one time. But I would instead say the situation is simply complicated and thus hard to predict by the average soap maker (as opposed to a soap chemist with a nice lab, willing grad students, and some research funding). Take each variable separately, and their effects are clear.

 

[MGM]

Thanks everyone, lots to read here and many rabbit holes to go down ;-)
I'm not sure about the gel, though: I put them in individual molds, so they likely didn't get warm enough to gel anyway? I also didn't insulate or wrap them at all (I rarely do). I'll open one up to see if there's partial gel, but how could I tell in a pure white bar if there's gel? TBH, I never notice gel or lack thereof in my loaf moulds, even.

 

[HowieRoll]

Ok so I've been using a variety of recipes and not paying all that much attention to water amounts. I decided to do 2 small unscented/uncoloured batches of the same recipe:

Coconut Oil: 20%
Lard: 30%
Olive Oil: 30%
Grapeseed Oil 15%
Castor Oil 5%
​

One used 1.5:1 water and the other used 2.65:1 water. I expected the one with less water to trace faster. It was exactly the opposite! It took 20 min of off-and-on aggressive stick-blending to get the 1.5 water even to light trace. The 2.65 water took longer than the other emulsify, but traced just a minute after that.
What's going on? Is that what's supposed to happen and I've just misunderstood it this whole time??

It's strange, isn't it?! A few years ago I tried my hand at an Auntie Clara Ghost Swirl, and was pretty shocked to see how slowly the low water portion of the soap came to trace. Since that time, I now typically soap between a 36-40% lye concentration and the biggest issue I have is getting impatient waiting for the batter to thicken enough. Many a swirl has turned out muddy because I threw in the towel and poured when the batter was still too runny. If I'm doing a soap where I need it to set up more quickly (i.e. layers), I will use around a 30-33% lye concentration.

(I also use soy wax now, and soap in the 120-130°F range - the higher temps have not affected time to trace, either).

 

[DeeAnna]

I can't always tell either, but here are some thoughts --

A partial gel can show even in an uncolored bar.

Look at the translucency of the soap, especially if uncolored but also if you've used a dye colorant (not micas or pigments). Soap that has gelled will appear more translucent than not-gelled soap. That takes a little experience with a given recipe, however. And the translucency varies with the predominant fatty acids in the soap -- I think high-palm or high-lard soaps are more translucent.

Yet another oddball clue is whether the soap "bounces" when a couple of bars are gently tapped together. You'll feel a tiny echo of a vibration after the tap if the soap has fully gelled. A not-gelled soap feels "dead" in that it doesn't vibrate. It's subtle, but interesting. This bounciness will be apparent after the soap has cured, gelled or not.

 

[szaza]

I've had a similar experience with a soap that I started at at 50% lye concentration. At emulsion I split the batter and added a colorant with the rest of the water and it immediately went from emulsion to medium trace.
Yesterday I had the opposite.. I started at 40% and wanted to add a colorant (+ extra water) at emulsion/light trace. I soaped a tiny bit warmer than I usually do (oils were just slightly warmer than room temp, I guess +-30C? Didn't measure) because I knew it would be slow (and I used 25%CO, 75% ho sunflower which is already super slow at 30-33% lye concentration) but after mixing the first colorant I turned back to my jug and it was volcanoing. The batter got so hot it left a mark on my pp jug (it was a tiny batch in a large jug, so no spilling or accidents). I don't know if the 40% was just enough water to get it to accelerate, if it was the bit of extra heat from the oils caused it or maybe.. don't know if it's possible.. I used the last bit of masterbatch solution, which was stored in a well rinsed liquid laundry detergent bottle. The bottle still smells of detergent and I wonder if some of the (floral) FO from the detergent could still have been in the container and soaked into my lye? There were some white floaties in the lye solution that didn't dissolve when I went from 50% to 40%. I just went with it because it was the last bit of lye I had (waiting for my order to arrive)
Sorry for the long post and a bit of sidetracking..

 

[Mobjack Bay]

Dunn's experiments I think you have in mind weren't studying "time to trace".

He was looking at the effect of various water contents and starting temperatures of the soap batter and how those variables affected the temperature during saponification. He also recorded whether the soap got hot enough to go through the phase change from solid to gelled soap (aka "neat" soap) and how this phase change also affected the temperatures during saponification.

His results weren't "inconclusive" really, but they certainly did prove you have to keep a number of variables in mind if you want to predict the behavior of soap during saponification. Here are some general observations I've drawn from his study --

Low water soap heats up faster and reaches a higher maximum temperature compared with high water soap, all other things being equal (AOTBE).

Low water soap can have a considerably higher gel temp than high water soap, AOTBE.

High temperature soap heats up faster and reaches a higher maximum temperature compared with lower temp soap, again AOTBE.

Soap that goes into the gel phase saponifies faster when it's in gel than soap that remains in the solid phase.​

When all of these variables are put together -- starting temp, water content, and phase change -- the results can seem inconclusive, because that's a lot of factors to juggle and interpret at one time. But I would instead say the situation is simply complicated and thus hard to predict by the average soap maker (as opposed to a soap chemist with a nice lab, willing grad students, and some research funding). Take each variable separately, and their effects are clear.

I found the text I was remembering. It’s in Chapter 23. Time to Trace:

pg. 325: “Because temperature and moisture concentration affect the rate of saponification, as explored in Chapter 22, we supposed that the time required to reach trace would depend on these factors as well.”

He then goes on to describe the method used to determine when trace was reached (soap viscosity) and the results of experiments to test the effects of temperature, water amount and eugenol content on time to trace for different recipes.

pg 328: “Figure 23.5 shows the viscosity of raw Olive 1000 Lye 262 as a function of time using several different water portions. We expected viscosity to rise most rapidly with low water content, and this is precisely what was observed for olive oil soap. The pattern was not as evident, however, for palm oil and Delight soaps [olive, palm, coconut and castor]. Generally, low water soaps thickened quickly and high water soaps slowly, but there was no clear pattern for the soaps in the middle. It may be that some uncontrolled factor prevented us from getting reproducible results in this part of the study. As it stands, we cannot recommend using water concentration to control the rate of viscosity change [time to trace] in raw soap.”

 

[MGM]

Ironically, I decided to undertake this experiment to better understand what affect lye concentrations have, and in order to be able to soap more consistently.
Suffice to say, it's a big FAIL on both counts.
Off to gently bounce my soap bars against each other....

 

[DeeAnna]

Thanks for finding the info, @Mobjack Bay. I stand corrected!

 

[Mobjack Bay]

Thanks for finding the info, @Mobjack Bay. I stand corrected!

It’s just one paragraph in a 400+ page book, which makes it pretty easy to miss.