Cooked soft soap paste turns from translucent to white after cooked!

[Sebastian]

Hi all! Lately I've been working on my soft soap paste and I've observed that every time after I left my cooked soap paste to cool, it always turns from translucent to white (as per the attached photo, the soap paste is slowly turning white).

Below are my formula:
50 g RBD palm olein
9.9 g KOH (100% purity assuming SAP of 0.198)
14.85 g of water
(overall it should be 0% superfat and 40% KOH concentration)

My main concern here is, is soap paste turning white (and lil bit harder) after cooled a normal phenomena? Or normally it should always stay translucent as it is?
Please also comment on any potential mistake that I've made here, thank you!

 

[Sebastian]

Up!

 

[Arimara]

Hi all! Lately I've been working on my soft soap paste and I've observed that every time after I left my cooked soap paste to cool, it always turns from translucent to white (as per the attached photo, the soap paste is slowly turning white).

Below are my formula:
50 g RBD palm olein
9.9 g KOH (100% purity assuming SAP of 0.198)
14.85 g of water
(overall it should be 0% superfat and 40% KOH concentration)

My main concern here is, is soap paste turning white (and lil bit harder) after cooled a normal phenomena? Or normally it should always stay translucent as it is?
Please also comment on any potential mistake that I've made here, thank you!
View attachment 46024

Liquid soap can be forgiving in some areas and allow for small batches but unless you make a batch that is no smaller than 300gs (400g is better) OR at the least have a very accurate jeweler's scale, you should not be making batches of soap this small under any circumstances. There could be any number of reasons with what went wrong here such as you actually using more lye than you would have liked. You should also call the company whom sold you the KOH and ask them about your batch's purity. It is not very common the even have KOH that pure, to my knowledge.

 

[Sebastian]

Hi Arimara, in the case of my KOH purity actually lower (<100%) than what I've assumed, I'm actually using less lye than I'd have right?

Does the whitening/solidification of soap paste usually related with using excess lye or excess fat in your opinion? I'd really appreciate it if you could point out any potential reason for this! Thanks!

 

[DeeAnna]

Warm the paste back up and see if it turns translucent again. Soap paste can change from opaque to translucent simply due to changing temperature. Or due to changes in water content. The picture shows opaque on top and more translucent on bottom -- could be from water difference (evaporation from the surface) or temperature difference. Or both.

You're using a lower water content than I would use. Although KOH soap can be made with up to a 50% lye concentration, I normally use 25% lye concentration. Due to your extremely small batch size, you're probably getting a lot of water evaporation on top of starting with less water than is typical. Try a higher water content and see if that makes a difference.

As far as excess lye or excess fat, the translucency of the paste doesn't necessarily tell you anything about that. You need to zap test. If there is no zap, the soap doesn't have excess lye. If there is a zap, then you either have excess lye or saponification is not yet done.

If no zap, then dilute the soap and see if you get a layer of fluffy white fatty acids floating on top of the soap. That will tell you if there's excess fat.

 

[Sebastian]

Hi, thanks for the reply! I've actually done 3 batches: 25%, 33% and 40% lye concentration. Appearance wise, 25% is more translucent and softer, when lye concentration increases the paste tend to become whiter (sort of like solidification but still soft). All 3 batches I've tested the pH its close to 10 (should be a safe value?). My concern or rather confusion here is only regarding the soap paste turning white when cooled, is that something that's not supposed to happen? Does it affect the performance of the soap and should i make sure that the soap is thoroughly translucent? I'm actually cooking them in an oven (105 degree C), any suggestion on the temperature? Thanks in advance!

 

[DeeAnna]

"...Appearance wise, 25% is more translucent and softer, when lye concentration increases the paste tend to become whiter ..."

Well then, stop and think about what you just said. Doesn't that information allow you to draw some conclusions about water content and translucency?

"...My concern or rather confusion here is only regarding the soap paste turning white when cooled, is that something that's not supposed to happen? ..."

I already said that translucency of soap can be affected by water content and temperature. A change in appearance due to different water content or due to changing temperature is normal.

"...I'm actually cooking them in an oven (105 degree C), any suggestion on the temperature? ..."

I don't cook my liquid soap paste when I make it. If your cooking at 105C, you're way plenty warm enough. If that works for you, then it works. You don't have to go that hot if you don't want to. When I do warm up my starting ingredients, I only go to maybe 180F / 80C with no added heat after the initial warming.

"...pH its close to 10 (should be a safe value?) ...

Soap pH ranges from about 9.5 to about 11.5 when the soap is properly made (no excess lye). The actual pH depends on the fatty acids involved.

The pH alone cannot tell you whether the lye is fully consumed. The zap test or an excess (free) alkalinity test is required for that.

 

[Saponificarian]

I think because you are using Palmolein, you are thinking it should be translucent like a soap paste made with Olive oil for example which is not true at all.

If you make a soap with an oil high in Palmitic acid and some stearic like you just did, you shouldn’t really expect it to behave like normal soap paste made with High oleic oils. Even at 25% lye concentration.

I make a 100% Tallow soap Paste which I then dilute with different type of pastes to make body wash. At 33%lye concentration, it is pure white and much like a hard soap dough.

Your paste is behaving as it should.

 

[Sebastian]

Thanks for the clarifications! One more thing I've been wondering is the thickening of soap. I've diluted my paste in water and it seemed very thin. Are there any simple ways that I can thicken it? And if so, what materials and which stage and the amount to be added?

 

[Sebastian]

"...Appearance wise, 25% is more translucent and softer, when lye concentration increases the paste tend to become whiter ..."

Well then, stop and think about what you just said. Doesn't that information allow you to draw some conclusions about water content and translucency?

"...My concern or rather confusion here is only regarding the soap paste turning white when cooled, is that something that's not supposed to happen? ..."

I already said that translucency of soap can be affected by water content and temperature. A change in appearance due to different water content or due to changing temperature is normal.

"...I'm actually cooking them in an oven (105 degree C), any suggestion on the temperature? ..."

I don't cook my liquid soap paste when I make it. If your cooking at 105C, you're way plenty warm enough. If that works for you, then it works. You don't have to go that hot if you don't want to. When I do warm up my starting ingredients, I only go to maybe 180F / 80C with no added heat after the initial warming.

"...pH its close to 10 (should be a safe value?) ...

Soap pH ranges from about 9.5 to about 11.5 when the soap is properly made (no excess lye). The actual pH depends on the fatty acids involved.

The pH alone cannot tell you whether the lye is fully consumed. The zap test or an excess (free) alkalinity test is required for that.

''I don't cook my liquid soap paste when I make it. If your cooking at 105C, you're way plenty warm enough. If that works for you, then it works. You don't have to go that hot if you don't want to. When I do warm up my starting ingredients, I only go to maybe 180F / 80C with no added heat after the initial warming.''

Meaning that you warm your starting ingredients (only oil and not KOH i assume?) to 80C, you stir them to trace and leave it as it is? Then how long will it reach the paste state from the trace state?

 

[DeeAnna]

Meaning that you warm your starting ingredients (only oil and not KOH i assume?) to 80C...

The batter is 80C. However you get the batter to 80C doesn't matter -- warm the fats, use hot KOH solution right after it is made, or warm the soap batter.

"..you stir them to trace and leave it as it is? Then how long will it reach the paste state from the trace state?..."

Yes, bring to a stable thick trace, and then stop cooking, cover the soap pot, and walk away. The time to finish saponifying is often well under 1 hour, but it can vary.

More info --

Irish Lass tutorial: Soaping 101 liquid soapmaking video? See posts 8 and 9

I recommend that people NOT use the method of dissolving KOH in hot glycerin as she describes in the first part of Step 3. Read and follow her directions in RED toward the end of Step 3 where she explains how to dissolve KOH in room temperature water. Much easier and safer.

Susie's tutorial: Cold Process Liquid Soap

Another good resource: Liquid Soapmaking – Where To Start

"...I've diluted my paste in water and it seemed very thin. Are there any simple ways that I can thicken it? ..."

Diluted liquid soap can be thin depending on the fatty acids in the recipe or if you over-dilute. Sometimes there are easy ways to thicken, sometimes not. I have more info in my articles here -- Soapy Stuff: Soapy Stuff