Lye Gel

[atiz]

I finally got time to make some salt bars yesterday. I went about it as usual. Dissolved the lye in equal amount of vinegar (stirred, made sure it did indeed dissolve, etc.), and left it alone, loosely covered, for a few hours while I had other things to attend to. By the time I got back to it, it turned into gelatin. There was no other ingredient added to the lye-water (lye-vinegar?), and the container was clean. I have never seen anything like this before -- does this just happen sometimes??? (It was the consistency of apple jelly, crystal clear, with no visible lye bits in it.)
ETA: I did a search on the forum but the cases where this comes up usually involve some kind of sugar in the lye-water. I had none.

Otherwise, it behaved fine. I spooned the gel into the oil & coconut milk combo, and soaping went as usual. I got some normal-looking soap at the end of it. But still, it was weird!

 

[DeeAnna]

"...left it alone, loosely covered, for a few hours while I had other things to attend to. By the time I got back to it, it turned into gelatin...."

What was the temperature of the lye solution when you noticed it had thickened?

 

[Anstarx]

I'm kinda curious why you dissolved your lye in vinegar? Isn't that a bit against the purpose of lye?
I know people add citric acid as lye discount, so is this like a way to superfat?

 

[cmzaha]

Did you use 50% Vinegar for dissolving your lye? Were was your extra liquid for dissolving your extra lye required for reacting the vinegar? Anyhoo when you dissolve lye in 50% vinegar and let it sit around for a few hours it will thicken as yours did once the lye reacts with the vinegar. If you really look at it you should have seen that it is tiny little balls of balls sodium acetate. At least that is what it looks like to me and I assume it is the sodium acetate. It will still work as you found out when you stir it in your other liquid and oils. This is why I do not advise master batching vinegar with lye for longer than same day soaping.

I forgot to mention DeeAnna, it will thicken at room temp. For me, room temp is when the outside of my plastic pitcher is slightly warm to the touch on the outside.

 

[Kosmerta]

What brand of vinegar did you use? The NaOH base would have reacted with the acetic acid to produce salt and water. Neither of these things are gelatinous so it sounds like the vinegar may have had some additives. Perhaps preservatives? Do you still have the bottle it came in and if so does it list ingredients?

 

[atiz]

"...left it alone, loosely covered, for a few hours while I had other things to attend to. By the time I got back to it, it turned into gelatin...."

What was the temperature of the lye solution when you noticed it had thickened?

I didn't measure, but it has completely cooled. (It was left alone for about 4 hrs in room temperature. It was about 70F in the room, average winter humidity (=dry). )

 

[atiz]

Did you use 50% Vinegar for dissolving your lye? Were was your extra liquid for dissolving your extra lye required for reacting the vinegar? Anyhoo when you dissolve lye in 50% vinegar and let it sit around for a few hours it will thicken as yours did once the lye reacts with the vinegar. If you really look at it you should have seen that it is tiny little balls of balls sodium acetate. At least that is what it looks like to me and I assume it is the sodium acetate. It will still work as you found out when you stir it in your other liquid and oils. This is why I do not advise master batching vinegar with lye for longer than same day soaping.

I forgot to mention DeeAnna, it will thicken at room temp. For me, room temp is when the outside of my plastic pitcher is slightly warm to the touch on the outside.

OK, this may explain it, thank you @cmzaha. This was not the first time I have worked with vinegar, but maybe I have never let it cool down so completely, I don't quite remember. I did not observe its structure very carefully because it was getting late and I still wanted to make some soap, but your description sounds right.

I used 50% of vinegar and added just a wee bit of water to make sure all the lye dissolves in it (I didn't do precise calculation for the water because figured it doesn't matter that much insofar as all the lye dissolves). The other part of my liquid was coconut milk mixed into the oils.

@Anstarx, I like using vinegar because it seems that my soaps lather more when I do (I think @DeeAnna explains the chemistry of it on her website but I wouldn't do a good job at that right now). The SMF calculator adjusts the lye amount if you put in vinegar as an additive, so there is no extra superfat (and it spares you doing the calculation manually).

@Kosmerta, it was regular 5% household vinegar. I do have the bottle but it doesn't say anything, and I would be very surprised if they had put preservative in vinegar!

Thanks all, I guess I have learned something new!

 

[DeeAnna]

@cmzaha -- Thanks for solving this particular mystery. I need to update my "soapy stuff" article about using vinegar to include this info, Carolyn. You'd mentioned this before, but I didn't follow up like I should have. I'll fix that today.

@atiz -- The reason why I asked about the temperature of your solution is this -- NaOH solution that is 50% NaOH and 50% plain water will thicken a lot if it cools below about 65F / 23C. It will pour like very cold honey. If it cools below 60F / 20C, it may become so thick it won't pour at all. That can be a real surprise. But that is not the situation here, so this tidbit doesn't apply to your mystery.

@Kosmerta -- Vinegar is self preserving if the acetic acid content is high enough. That's why commercial vinegar is 5% acetic acid or higher. As far as your other comment about the thickening -- Carolyn explained that the sodium acetate forms small droplets in the NaOH solution. This is telling me the mixture is a colloid. In this case the colloid is an emulsion of sodium acetate droplets suspended in lye solution. A colloid is always thicker than either of the two liquids alone. Soap batter is also a colloid (or emulsion) of fat droplets suspended in lye solution. This emulsion is also thicker than either the lye solution or the fat mixture alone.

edited for clarity

 

[cmzaha]

@Kosmerta -- Vinegar is self preserving if the acetic acid content is high enough. That's why commercial vinegar is 5% acetic acid or higher. Carolyn explained that the sodium acetate forms small droplets in the NaOH solution. This is telling me the mixture is a colloid. In this case the colloid is two liquids sodium acetate droplets suspended in lye solution. A colloid is always thicker than either of the two liquids alone. Soap batter is also a colloid or emulsion -- fat droplets suspended in lye solution -- and it too is thicker than either the lye solution or the fat mixture alone.[/QUOTE]

Thankyou DeeAnna, I just knew you would put it in much better chemistry type terms for me. To me, it was tiny little balls for lack of a better term.

 

[atiz]

Thank you all, glad it's been solved
Next time, I won't let it cool that much or just won't get scared if it jellifies. Chemistry is like magic

 

[DeeAnna]

@cmzaha -- Carolyn, does a vinegar-lye solution "gell-ify" if the NaOH concentration is less than 50% -- say more like the usual 28% to 35% concentrations that many people use. Or does this happen when the NaOH is at the max of 50%?

 

[cmzaha]

I have made it with a 33% concentration which has sat around for 6 hrs or so. It formed some droplets (balls of sodium acetate ) but not the actual gelling as with the 50%, I really cannot remember if they were actually suspended throughout the solution, but do remember they were stuck to the sides, and I think they were more on the top. Sorry, I should have taken notes. The next time I make soap I will pay more attention, by actually taking temps and using full vinegar and 50% vinegar. Maybe next week.

 

[DeeAnna]

Thanks, Carolyn! You're being generous to share your experience, and I appreciate that.

 

[Rsapienza]

The SMF calculator adjusts the lye amount if you put in vinegar as an additive, so there is no extra superfat (and it spares you doing the calculation manually).

I did not know that SMF calculator did this for me. I researched so many threads to find out how to do the calculation. I used a 50/50 MB lye & water and used vinegar as my extra liquid. It only ended up being like 0.13g extra NaOH and I did a 5% SF. The soap seems fine. I'm guessing since it was such a little amount, I'm ok??? I'm glad I read this today. Thank you.

Now I'm thinking...should I have added the vinegar (listed as an additive) and the extra liquid amount?

 

[atiz]

I did not know that SMF calculator did this for me. I researched so many threads to find out how to do the calculation. I used a 50/50 MB lye & water and used vinegar as my extra liquid. It only ended up being like 0.13g extra NaOH and I did a 5% SF. The soap seems fine. I'm guessing since it was such a little amount, I'm ok??? I'm glad I read this today. Thank you.

I didn't know it for a long time either! Then once printed out a recipe from SMF without vinegar and then the same recipe with vinegar, and noticed that there was a difference in the lye amount -- so I figured the vinegar was adjusted for.
But I think you should be fine; the most that happens is a little bit of extra superfat, right?

 

[Rsapienza]

I didn't know it for a long time either! Then once printed out a recipe from SMF without vinegar and then the same recipe with vinegar, and noticed that there was a difference in the lye amount -- so I figured the vinegar was adjusted for.
But I think you should be fine; the most that happens is a little bit of extra superfat, right?

Awesome...but I'm still confused about the total amount of extra liquid I should have used. I added the vinegar in the additive section to use as my extra liquid. But up in the liquid and lye section, it also has the same amount for liquid required. So instead of adding 4.63 oz of extra liquid (which was the vinegar), should I have actually doubled that? I hope this makes sense.

 

[cmzaha]

@Rsapienza, if you are going to use vinegar and 50/50 masterbatch in soapmakers friend turn on the box for using masterbatch. Then use 1:1 if your masterbatch is 50/50. Now go to the additives and choose vinegar. Check your recipe totals to see how much liquid you can use so you know how much vinegar you are able to use. Now pick how many oz or grams of vinegar you want to include and fill in the box with the appropriate amount. The program will now up the correct amount of extra masterbatch and up a small amount of liquid. What you want to remember to do is deduct the amount of vinegar from your required liquid. The program does not do that for you. This only applies if you are letting Soapmakers Friend Calculator do the math for you. It is very important that you verify whether you are using grams or ounces when marking the box for vinegar.

If you want to manually figure out vinegar usage you figure out your water and NaOH requirements decide how much you want to replace with vinegar then multiply the vinegar amount by 0.0357 to get the appropriate extra NaOH required. So if you were to use 8 oz or 226 g of vinegar you would need 8 g extra NaOH. Hopefully I did not make it to confusing

 

[Rsapienza]

@Rsapienza, if you are going to use vinegar and 50/50 masterbatch in soapmakers friend turn on the box for using masterbatch. Then use 1:1 if your masterbatch is 50/50. Now go to the additives and choose vinegar. Check your recipe totals to see how much liquid you can use so you know how much vinegar you are able to use. Now pick how many oz or grams of vinegar you want to include and fill in the box with the appropriate amount. The program will now up the correct amount of extra masterbatch and up a small amount of liquid. What you want to remember to do is deduct the amount of vinegar from your required liquid. The program does not do that for you. This only applies if you are letting Soapmakers Friend Calculator do the math for you. It is very important that you verify whether you are using grams or ounces when marking the box for vinegar.

If you want to manually figure out vinegar usage you figure out your water and NaOH requirements decide how much you want to replace with vinegar then multiply the vinegar amount by 0.0357 to get the appropriate extra NaOH required. So if you were to use 8 oz or 226 g of vinegar you would need 8 g extra NaOH. Hopefully I did not make it to confusing

Not at all and that's exactly what I did. The first time, I calculated myself. This time, I got confused by having 2 separate liquid spots. I did enter the extra liquid amount into the vinegar amount but still seeing the extra liquid confused me. I'm definitely over thinking this. Thank you for the clarity.

 

[atiz]

@Rsapienza, @cmzaha's solution works, but I think (at least for me) there is an even easier one: on SMF, when you choose vinegar as additive, there is an optional box you can check for "liquid discount". By default it's off, but if you turn it on, then the amount of vinegar will be subtracted from your water amount. So SMF will do that part of the math too and then it will just tell you to use x g of vinegar and the remaining y g of water (or whatever). (I often do full water replacement with vinegar and then just play with it till the "water" part is nearly 0.)

 

[cmzaha]

@Rsapienza, @cmzaha's solution works, but I think (at least for me) there is an even easier one: on SMF, when you choose vinegar as additive, there is an optional box you can check for "liquid discount". By default it's off, but if you turn it on, then the amount of vinegar will be subtracted from your water amount. So SMF will do that part of the math too and then it will just tell you to use x g of vinegar and the remaining y g of water (or whatever). (I often do full water replacement with vinegar and then just play with it till the "water" part is nearly 0.)

I tried that and it did not deduct the vinegar from the water amount. I will try again. a atiz Unless I am brain dead tonight and that is always possible if you turn on masterbatch I do not find that it deducts the vinegar amount when you turn liquid discount. The liquid requirement stays the same. Please correct me if I am wrong. It does deduct the vinegar from the liquid requirement if masterbatch is turned off. I still do this part of the math myself and do not depend on the program to do it for me.