Citric Acid Disaster, I think...

[Na7asha7aylor]

Hi Everyone, I'm new to soaping and I have a question about the addition of Citric Acid in the water reserved for the lye solution: so here it goes: Twice, I have made a small batch of soap, wherein I dissolved (into the 65g of water reserved for my 65g of lye) Citric Acid at 2%, fine mesh silk powder and powdered sugar.

It dissolved as you would expect it to..then comes the lye...

Once added the solution turns a light yellowish tint, which isn't what concerns me (though maybe it should)....anyways, I was letting it cool and sit overnight, and I woke up to a thick milky crystal & grainy sludge....

Now I have read up on Citric Acid...(and Sodium Citrate), am I NOT supposed to let it sit? Does it need to be used immediately???

I thought maybe it was like what I read about Stearic Acid and how it needs to be soaped really hot, otherwise the SA won't stay melted...Is that what's happening here? I saw a similar post, but it didn't make it clear to me what I should be doing, and if this is normal...Are these two batches now trash?? And just to provide more info that may or may not be relevant: The remaining liquid for the lye, is coconut milk, which I added with the oils, and I didn't calculate the NaOH for the Citric Acid, since it is my understating is that this forum's SoapCalculator does that calculation for you (at least it appears to...) Thanks so much!!

 

[ResolvableOwl]

Welcome to SMF, @Na7asha7aylor !

I thought maybe it was like what I read about Stearic Acid and how it needs to be soaped really hot, otherwise the SA won't stay melted...Is that what's happening here?

No. Stearic acid won't dissolve into water, and is used in soap as part of the oils. In some way, it is very prone to false trace, that is an issue with oils. Citric acid, on the contrary, readily dissolves in water (and lye), and will stay so unless you're reaching very high concentrations.

Let's see if I have understood your process right. The steps of your water phase are:

1. Dissolve about 10 g citric acid (2% of what I guess is 500 g oils) into 65 g water
2. Try to dissolve 65 g NOH into this.
3. Mix with coconut milk (after combining with the oils).

Step 2 is indeed problematic. Around room temperature, the maximum concentration of aqueous NaOH is around 50%, so you are indeed in the “very high concentrations” regime as mentioned above. Either citrate or hydroxide will lose (have to precipitate) with that little water, usually the hydroxide wins, and you'll have clumps of citrate that will or will not dissolve in the coconut milk.

Step 3 is also not as straightforward as it sounds. Coconut milk won't dissolve in oils, but forms an (unstable) emulsion. Lye will do brutal things to this emulsion. You won't have an advantage from this way over adding the coconut milk to the aqueous phase before. On the other hand, dissolving NaOH in coconut milk is possible, but not easy either, since you have to prevent heating up and premature trace.

Why not:

1. dissolve the citric acid into the coconut milk (it doesn't matter when it curdles, it would have done so anyway when lye added)
2. dissolve the NaOH into the water 1:1, let cool to room temperature
3. mix the acidic coconut milk and the lye
4. pour into oils (through a strainer), stir, SB, …
5. (Disclaimer: I haven't tested this. When you try this, ,make sure you take notes and post them here. BTW, SMF loves photos!)

When you're adding citric acid, it is imperative to raise NaOH to make up for the lye that the citric acid will eat up to form sodium citrate. This is easy to calculate: every 7 g of citric acid need an extra 4 g of NaOH (still, some soap calculators manage to do it wrongly).
It's also a good idea to include the amount of fats of coconut milk to the oils (regardless if you add the coconut milk to the oils or the aqueous phase).

 

[Na7asha7aylor]

Thank you so much for your reply! I will definitely try this out and report back.
About my steps:

1. Dissolve about 10 g citric acid (2% of what I guess is 500 g oils) into 65 g water Yes, along with the powdered sugar and silk mesh.
2. Try to dissolve 65 g NOH into this. Yes, after about 20 mins and making sure the water solution additives were dissolved
3. Mix with coconut milk (after combining with the oils). Yes? Just to confirm I understand, the coconut milk was added to the lye & oil mixture....so what you're saying is that the coconut milk won't dissolve/emulsify? I know youtube isn't the authority on tutorials, but I've seen so many add their milks in (goat and coconut) this way...no bueno?

Are you maybe indicating that this soap calculator may not be the best? I feel like a lot of people use another popular one...I liked this one because it had a good selection of additives and was well "organized", but if it's not that accurate....definitely a good idea to have the math to fall back on, in case these cals are inaccurate or unavailable. I was aware that i may need to adjust the NaOH to accommodate the CA, but I just took for granted that the cal worked, especially since a forum search confirmed that this function was built in...I mean I don't check the lye math..so you know

When you mentioned adding the fats of the coconut milk to the oils, I'm not sure what you meant "It's also a good idea to include the amount of fats of coconut milk to the oils (regardless if you add the coconut milk to the oils or the aqueous phase)." Do you mean like in the drop down for the oils?

I obviously don't have as much knowledge as I thought and nothing beats actually doing it

Thanks so much!

 

[AliOop]

What Owl is trying to tell you is that you need at least a 1:1 ratio of water to NaOH. Once you have stirred in an amount of NaOH that is equal to the amount of water, the water cannot hold anything else in solution. Whatever else will be added, or previously was added, will not stay dissolved.

In your case, that means you cannot dissolve anything else in your 65g of water - because you are maxed out at 65g of NaOH. That's why you have crystals and graininess - you tried to add the maximum amount of NaOH after already using some of the water for the citric acid AND the sugar. And that's why Owl is suggesting that you dissolve the citric acid and sugar in the coconut milk instead of the water.

I personally don't make my citric acid/sugar solution ahead of time. If you decide to do that, you will want to refrigerate it, as it can go bad pretty quickly. But I do masterbatch my water-lye solution, and I do put tussah silk to it. The silk doesn't really dissolve as much as it disintegrates into smaller particles that may sink to the bottom. That's ok, since they will get blended in later anyway. The same isn't true for citric acid or sugar; they need to actually be dissolved, or you will have graininess in your soap.

Regarding the fat in the coconut milk, I personally don't worry about that. But my superfat is always low - 2-3% max, so a little extra fat from the coconut milk doesn't throw things out of whack too badly. If you already have a high superfat, then definitely think about accounting for that extra oil.

As for the extra lye needed for the CA, yes, the SMF calculator will work that out for you, if you click YES where it asks, Liquid Discount? (undernearth the citric acid selection).

HOWEVER! The citric acid calculator function doesn't seem to work when you have also selected the master-batched lye option (this known glitch is also true for the vinegar adjustment when using MB lye). To be safe, manually calculate the extra NaOH for citric acid using the numbers provided by @ResolvableOwl.

 

[ResolvableOwl]

@AliOop covered most of the points . Just addressing a few minor open points about coconut milk:

Mix with coconut milk (after combining with the oils). Yes? Just to confirm I understand, the coconut milk was added to the lye & oil mixture....so what you're saying is that the coconut milk won't dissolve/emulsify? I know youtube isn't the authority on tutorials, but I've seen so many add their milks in (goat and coconut) this way...no bueno?

Coconut milk is an emulsion by itself: coconut oil dispersed in water, along with some solids of the coconut pulp. Depending if it has additives (gums, emulsifiers) or not, it might be more or less stable by itself. When you mix it into a blend of liquid/molten oils, this system gets a bit out of balance: it becomes less stable against disturbances like high salt concentration (NaOH is a salt!) and heat. In my experience, there is just no way to salvage a watery-something-in-oils emulsion when adding lye solution. The emulsion will collapse (and re-form later on when the saponification kicks in).

And regarding superfat/oil content of coconut milk: It's something you can include into the oil blend of the recipe, but with the absolute numbers in mind, it doesn't make a huge difference.
Example: Say you're adding a generous 100 g coconut milk per 500 g oils. At typical 20% fat content (check the nutritional information!), this is 20 g of extra coconut oil, that's 4% of the oils. It is on the order of typical superfat numbers, that's why some dial 0% SF in the calculator when they use extra coconut milk.
If you're paranoid about fatty acid profile, then it's not difficult to just lift CO in the recipe by said 20 g.

 

[ResolvableOwl]

nothing beats actually doing it

 

[Na7asha7aylor]

What Owl is trying to tell you is that you need at least a 1:1 ratio of water to NaOH. Once you have stirred in an amount of NaOH that is equal to the amount of water, the water cannot hold anything else in solution. Whatever else will be added, or previously was added, will not stay dissolved.

In your case, that means you cannot dissolve anything else in your 65g of water - because you are maxed out at 65g of NaOH. That's why you have crystals and graininess - you tried to add the maximum amount of NaOH after already using some of the water for the citric acid AND the sugar. And that's why Owl is suggesting that you dissolve the citric acid and sugar in the coconut milk instead of the water.

I personally don't make my citric acid/sugar solution ahead of time. If you decide to do that, you will want to refrigerate it, as it can go bad pretty quickly. But I do masterbatch my water-lye solution, and I do put tussah silk to it. The silk doesn't really dissolve as much as it disintegrates into smaller particles that may sink to the bottom. That's ok, since they will get blended in later anyway. The same isn't true for citric acid or sugar; they need to actually be dissolved, or you will have graininess in your soap.

Regarding the fat in the coconut milk, I personally don't worry about that. But my superfat is always low - 2-3% max, so a little extra fat from the coconut milk doesn't throw things out of whack too badly. If you already have a high superfat, then definitely think about accounting for that extra oil.

As for the extra lye needed for the CA, yes, the SMF calculator will work that out for you, if you click YES where it asks, Liquid Discount? (undernearth the citric acid selection).

HOWEVER! The citric acid calculator function doesn't seem to work when you have also selected the master-batched lye option (this known glitch is also true for the vinegar adjustment when using MB lye). To be safe, manually calculate the extra NaOH for citric acid using the numbers provided by @ResolvableOwl.

Thanks so much!! This is all great info and so well explained!

Just so I'm clear, that extra NaOH (due to the addition of CA) is required regardless if I'm adding the CA to the Lye solution or the remaining liquids added to the oils, right?

And also thanks because you brought up another question I keep trying to get another explanation for and that is: When do I know if I need, and what exactly does it mean "Liquid Discount??".. It's one of those things that I thought I knew, but if you asked me to explain it, I wouldn't be able to, which tells me I probably have over complicated it, which is why I can't understand it (That happens to me all the time lol) . So, Thanks and Thanks again to you both!! I'll report back once I've tried all your suggestions

 

[AliOop]

Just so I'm clear, that extra NaOH (due to the addition of CA) is required regardless if I'm adding the CA to the Lye solution or the remaining liquids added to the oils, right?

Correct. But you still can't add the CA to the lye solution unless you have more water than NaOH. Anytime you have equal water and NaOH, you can't add anything else to that mixture. It sounds like you understand that, so forgive for just making sure.

I personally never use the term "water discount" because there is no standard meaning for that term; people have different ideas about what is "full water." Instead, it's easier and more accurate to refer to your lye concentration. Using the lye concentration setting in the soap calculator instead of "water as percent of oils" will give you more consistent batches, especially as you scale up or down.

A pretty common starting point for lye concentration is 33%. If you want to try using less water (perhaps to reduce ash or glycerine rivers), you can raise your lye concentration to 35%, or even 40%. For my recipe, trace speeds up at 35% but slows down again around 38-40%. Likewise, if you want to try using more water (perhaps for a more fluid batter for swirls, or because you have a lot of fast-tracing ingredients), you might reduce your lye concentration down to 30%.

Similarly, instead of lye discount, it's easier to think in terms of superfat. That is a simple setting in all lye calculators and takes all the guesswork out of it.

HTH and good luck with your next batches.