Is this right ? (Lye concentration)

[CecileBC]

Hi all !

Hope you're well !

Could I just ask confirmation for what I think I understood about lye concentration :

I have been soaping at 33% or at 40% lye concentration, without knowing why.
After researching this forum, here is what I understood:

- More lye = less water. Resulting in less chances to get soda ash. But it means "thicker" and "faster moving" batter which may be harder to work with for designs. It can be ok if the oils used do not need to be warmed and worked with at high temperatures, as they stay fluid longer.
- Less lye = more water. Easier for designs, but more prone to soda ash (sometimes even when the soap is gelled). Good for oils that need to be worked at higher temperatures, as the extra water will help to keep them fluid longer.

If this is right, can I ask what would happen to have a high lye concentration (say 40%) with oils that need high melting temps, but we only reach a very light trace before adding whatever in the batter for designs (colour, scent, clays...), and pour when the batter reaches the right consistency without stick blending ? The batter may thicken too quickly anyway ? I guess finding the exact combo is the art of soapmaking, right ? (... I have remained in my comfort zone so far, and haven't had the courage to try designs yet...)

 

[KiwiMoose]

For any given recipe when using the 'lye concentration' setting the amount of lye will always be the same. My recipe always requires 137g lye for my blend of 1kg oils. Now, if I increase the lye concentration to say, 40%, my amount of lye does not increase, because that's the amout of lye needed to saponify my oils. What will change is the amount of water that goes into recipe. If it's Lye conc 40% there will be less water than if it's lye conc 33%. The 'concentration' refers to the amount of water in relation to the lye only.

 

[CecileBC]

For any given recipe when using the 'lye concentration' setting the amount of lye will always be the same. My recipe always requires 137g lye for my blend of 1kg oils. Now, if I increase the lye concentration to say, 40%, my amount of lye does not increase, because that's the amout of lye needed to saponify my oils. What will change is the amount of water that goes into recipe. If it's Lye conc 40% there will be less water than if it's lye conc 33%. The 'concentration' refers to the amount of water in relation to the lye only.

Of course !!!!! I remember now watching Elly's everyday video on this a few months ago....and I simply forgot ! Thanks !

 

[KiwiMoose]

Of course !!!!! I remember now watching Elly's everyday video on this a few months ago....and I simply forgot ! Thanks !

It took me forever to understand this concept - like the first 2 years of making soap almost.

 

[CecileBC]

It took me forever to understand this concept - like the first 2 years of making soap almost.

Thank goodness I feel less alone It's the name that's confusing...

 

[AliOop]

I regularly soap at 40% lye concentration to help offset the fact that I soap at room temp (which can result in lots of soda ash, at least for my recipe). I usually blend to emulsion or light trace, with no problems.

The lower amount of water also helps me unmold faster. Great for impatient people, if you happen to be one of those people, like, umm, some of my friends are.

 

[CecileBC]

I regularly soap at 40% lye concentration to help offset the fact that I soap at room temp (which can result in lots of soda ash, at least for my recipe). I usually blend to emulsion or light trace, with no problems.

The lower amount of water also helps me unmold faster. Great for impatient people, if you happen to be one, like, umm, some of my friends.

Ahah Yes ! the wait is incredibly loooooonnnngggg !!!

 

[TheGecko]

There is no such thing as "more lye" or "less lye"....the amount of Sodium Hydroxide being used in the Lye Solution does not change because it is based on the amount needed to turn your oils/butters into soap...so changing the amount of water being used to dissolve it, doesn't not change the amount being used.

The amount of water being used can have an effect on your soap making, but it's not absolute. Take Soda Ash...I use the same recipe, pretty much the same 33% Lye Concentration...I can have two loaf molds filled from the same batch and one will get SA and the other won't.

The only ingredient that I know of that needs a high temp to stay fluid is wax (soy 130F, bees 140F), but elsewise it seems that most hard oils and butters are fluid at around 100F and I haven't had any issues soaping at 80F-90F and my recipe is 65% hard oils (Palm/Coconut Oil, Cocoa/Shea Butter).

While temperature and water can affect 'play time', I have found colorants, scent and stick blenders have a greater effect.

 

[CecileBC]

The amount of water being used can have an effect on your soap making, but it's not absolute. Take Soda Ash...I use the same recipe, pretty much the same 33% Lye Concentration...I can have two loaf molds filled from the same batch and one will get SA and the other won't.

... adding a little spice to soapmaking, never being sure of the outcome !

The only ingredient that I know of that needs a high temp to stay fluid is wax (soy 130F, bees 140F), but elsewise it seems that most hard oils and butters are fluid at around 100F and I haven't had any issues soaping at 80F-90F and my recipe is 65% hard oils (Palm/Coconut Oil, Cocoa/Shea Butter).

Ok, thanks, I'll just have to try what happens with my own recipe.

All in all, I understand that the best way to learn how a recipe behaves is to make it !

 

[KiwiMoose]

I use soy wax at 20% and regularly soap at temperatures below 50 degrees, and even below 40 degrees (100)

 

[Mobjack Bay]

I started making soap using 40% lye concentration about 2 years ago, I think, and will never turn back. The soap comes out of the mold cleanly within 18 hours and I almost never get soda ash. I don't find that it makes my batter "faster" or "thicker," but this may be because I tested a lot of different recipes and methods. Based on my experiences, some fats, like lard, tallow, soy wax, olive oil (not pomace) and HO sunflower oil are relatively easy to formulate into "slow" recipes even if the Palmitic + Stearic is > 30%, which is about where I like my soaps to be. I've settled into a high lard + tallow recipe that works well if I start with the melted and cooled fats at around 85-90F, a tallow recipe that I like to start at 95-100F, and a soy wax recipe (GW 415; plus cocoa butter and/or shea butter) that I start at 110-115F. I usually have the lye at room temperature (70F). I let the fats cool down a bit more (-5F) if I know the FO or EO blend or an additive will cause acceleration or heating, and start warmer if I know the scent will decelerate. Palm is a little different for me and especially if there is castor oil in the recipe. I don't have any issues getting a nice fluid batter when I make a palm soap that has less p+s (= 25-27%), for example with the palm at 20-25%,10% shea and 5% castor oil, but if I increase the palm to 30% (for p+s = 29 or 30%) the recipe won't be reliably fluid enough for a Taiwan swirl even if I use 33% lye concentration and hand stir. My best advice is to test for any differences with your recipe by making test batches (450 g of fats) at 33% and again at 40% lye concentration. If you do, I hope you will let us know how it goes .

 

[CecileBC]

I use soy wax at 20% and regularly soap at temperatures below 50 degrees, and even below 40 degrees (100)

Thank you again

 

[CecileBC]

I started making soap using 40% lye concentration about 2 years ago, I think, and will never turn back. The soap comes out of the mold cleanly within 18 hours and I almost never get soda ash. I don't find that it makes my batter "faster" or "thicker," but this may be because I tested a lot of different recipes and methods. Based on my experiences, some fats, like lard, tallow, soy wax, olive oil (not pomace) and HO sunflower oil are relatively easy to formulate into "slow" recipes even if the Palmitic + Stearic is > 30%, which is about where I like my soaps to be. I've settled into a high lard + tallow recipe that works well if I start with the melted and cooled fats at around 85-90F, a tallow recipe that I like to start at 95-100F, and a soy wax recipe (GW 415; plus cocoa butter and/or shea butter) that I start at 110-115F. I usually have the lye at room temperature (70F). I let the fats cool down a bit more (-5F) if I know the FO or EO blend or an additive will cause acceleration or heating, and start warmer if I know the scent will decelerate. Palm is a little different for me and especially if there is castor oil in the recipe. I don't have any issues getting a nice fluid batter when I make a palm soap that has less p+s (= 25-27%), for example with the palm at 20-25%,10% shea and 5% castor oil, but if I increase the palm to 30% (for p+s = 29 or 30%) the recipe won't be reliably fluid enough for a Taiwan swirl even if I use 33% lye concentration and hand stir. My best advice is to test for any differences with your recipe by making test batches (450 g of fats) at 33% and again at 40% lye concentration. If you do, I hope you will let us know how it goes .

Thank you Mobjack Bay,
My notebook is full ! It helps a lot to have your feedback.
Once I have done the test batches, I'll make sure to post the results.

 

[dibbles]

The High Water-Low Water SMF challenge is a good example of how low water (higher lye concentration) can actually slow trace. Here are links to the videos @newbie made to demonstrate the technique. The second video is where you can see the difference. The only caution using a high lye concentration (low water to lye ratio) is with fragrance. If the FO/EO accelerates at all, the batter will thicken very fast. But you probably won't have soda ash
www.youtube.com/watch?v=zhkbIOXN1KM
www.youtube.com/watch?v=GGnjTg-LW_w

 

[CecileBC]

The High Water-Low Water SMF challenge is a good example of how low water (higher lye concentration) can actually slow trace. Here are links to the videos @newbie made to demonstrate the technique. The second video is where you can see the difference. The only caution using a high lye concentration (low water to lye ratio) is with fragrance. If the FO/EO accelerates at all, the batter will thicken very fast. But you probably won't have soda ash
www.youtube.com/watch?v=zhkbIOXN1KM
www.youtube.com/watch?v=GGnjTg-LW_w

Hi Dibbles,
Interesting videos thank you ! Especially since the high water batch went to a much thicker trace than the low water one; I would never have thought....
I had read about the "ghost swirl" technique with high water / low water. Beautiful effect.

 

[dmcgee5034]

The High Water-Low Water SMF challenge is a good example of how low water (higher lye concentration) can actually slow trace. Here are links to the videos @newbie made to demonstrate the technique. The second video is where you can see the difference. The only caution using a high lye concentration (low water to lye ratio) is with fragrance. If the FO/EO accelerates at all, the batter will thicken very fast. But you probably won't have soda ash
www.youtube.com/watch?v=zhkbIOXN1KM
www.youtube.com/watch?v=GGnjTg-LW_w

Wowwwwwwww! WAIT A MINUTE - mind blown!
THAT was fascinating! Thank you so much for posting the links, @dibbles
I feel like there is a chemistry lesson behind what I saw - what is happening - or not happening - in the low water that it stays so fluid??
I feel like I need to invoke @DeeAnna here to help us (aka me) understand, because I’m really boggled.

 

[DeeAnna]

For recipes using lye concentrations up to about 40%, it generally seems to be true that more water usually increases the time to trace, all other things being equal. I think that's why the usual advice given to beginners is to use more water. Unfortunately, other problems start happening as more water is used, including the soap batter separating in the mold or the soap staying way too soft for too long.

I think the sweet spot that works for most people most of the time is around 30% to 33% lye concentration (LC). A 30% LC is the same as a 2.3 water:lye ratio. A 33% LC is the same as a 2.0 water:lye ratio.

I'm digressing -- back to the higher lye concentration thing.

What I've seen and what others report is the time to trace often slows down when using a lye concentration at or above 40%, all other things being equal. But I don't have a surefire explanation about why -- just a guess --

Normally, NaOH will completely dissociate when mixed with water. What dissociation means is each NaOH molecule will split into two ions (electrically charged atoms), a sodium Na+ ion and a hydroxide OH- ion.

NaOH will always completely dissociate when the lye concentration is low enough.

Based on what we're seeing about soap being slower to trace when the lye concentration is very high, I'd say "low enough" is a lye concentration below about 40%.

If an NaOH solution is more concentrated than about 40%, however, my guess is not all of the the NaOH molecules can fully dissociate (split apart).

This makes the NaOH less able to chemically react with the fats in the soap batter. You have to have the Na+ ions and OH- ions free to do the saponification -- it's not the NaOH molecule that does this work.

But that's just my guess.

 

[Mobjack Bay]

@DeeAnna I don’t end up with soap that zaps when I use 40% lye concentration. That would be after 18 hours, which is when I usually take my soap out of the mold. Is that consistent with what you’ve written above?

 

[dmcgee5034]

Thank you, @DeeAnna

 

[DeeAnna]

@DeeAnna I don’t end up with soap that zaps when I use 40% lye concentration. That would be after 18 hours, which is when I usually take my soap out of the mold. Is that consistent with what you’ve written above?

I don't recall soap made with lye at 40% or higher concentration being zappy after a reasonable amount of time (18-24 hr). "Time to trace" and "time to zap free" are two different things in my thinking.

Assuming my thinking is anywhere reasonably close to correct, the rate of reaction would be slow at first due to the high (40%+) lye concentration. This would explain the longer time to trace.

But as some time goes on, there would be less and less interference with the remaining Na+ and OH- ions as more and more NaOH is consumed by saponification. So I'd expect the rate of saponification would return to "normal" rates when the NaOH concentration drops below that mysterious 40% concentration barrier.

The initial slow saponification step might only take an hour or three, depending on the soap temp and the fatty acids involved. Then back to business as normal.

It seems like a reasonable hypothesis anyway.