Split batch problems - Need help

[jblaney]

I feel stupid asking this, but I've had to toss three small batches this week and I'm not exactly sure what is happening.

All three batches did not set up and all three were split. When I say split, I mean I weighed the oils and lye/water, then I split the oils in half and split the lye/water in half and mixed them to trace separately.

The first part of the batch works out fine, but the second stays soft. I did not weigh the lye/water for the second half of the batch since I weighed the first half and just used the rest of it for the second half.

What I'm thinking is happening is there is evaporation with the lye/water from the heat generated and by not weighing out both parts I'm using too much in the first half and not enough in the second.

I have tested my scale and it works perfectly. I actually have two scales and I know the weights are accurate. I have never had this happen and I'm baffled by it. Any thoughts?

 

[Ruthie]

I don't have an answer but a suggestion. Why not make it as all one batch then split for the additives you are using.

 

[The Efficacious Gentleman]

I agree with Ruthie - make one batch to a light trace and then split it out.

 

[jenneelk]

I do splits a lot but I never split the oil and water. I add everything, bring just to emulsify then split. My batches always come out fine.
Try that way first then if still a problem, I'd look at the recipe.
Have u used this recipe before without splitting?

 

[jblaney]

Thank you everyone for your input and thoughts.

I have used this recipe many times and it's a good one with no issues.

I was splitting it since it starts to thicken up if I let it sit. I don't like to feel rushed. My recipe has a lot of hard oils, but I really like it.

I think I just won't split it any more.

 

[The Efficacious Gentleman]

You could look at upping the water a touch, that would give you a bit more time

 

[saffy]

You could try a lower mixing temp to avoid the need to split. I make small batches (1-3 kg) and usually mix at about 32-34'C (which I think is lower than most people), and use NaOH at 33% w/w (also lower than many savonnieres) - might also give you a bit more time.

Good luck

 

[Todd_in_Minnesota]

I do what Ruthie recommends too - BUT...
One caveat to watch out for, if you're splitting the already-mixed batch! (I just had a fail tonight doing exactly this same thing.)
I had planned to split my mix 70/30, each part to get it's appropriate color & scent.
I mixed the liquid oils first, and split them 70/30, then mixed into each it's colorant to get them into solution.
Then I weighed & melted the solid oils, adjusted the temp to barely-warm, and mixed in the lye water. No problem yet.

I also planned to have the 30% part trace sooner than the 70% part, so I wanted to make sure neither one traced prematurely.
So - after pouring the lyewater into the melted solid oils, I did a quick mix only before I split the two parts out.

Now, to split the mix into their prepared liquid-oils&colorant bowls...
Unfortunately, as I poured the mix I realized that the 30% part that I poured first was almost entirely oils, leaving the 70% part in the tub which was almost entirely lyewater.
The quick-mix I'd done after adding the lyewater hadn't completely mixed the lye&oils, and the almost-pure oils had floated to the top, which i then poured off disproportionately.
Now I had my 30% color with almost no lye, so it would never trace, and my 70% color was lye-heavy and tracing before my eyes.

Unrecoverable fail... only solution was to abandon the split plan and just pour it all into one tub.
I now have a mold full of grey-green disappointment. It'll smell good, and clean OK, but it's not what I'd hoped for.

TL;DR - mix well, then split.

Best Luck
Todd

 

[CanaDawn]

I agree....mix then split, but if it isn't working and you don't want to make a large batch and divide it at emulsion, then why not measure as if for two smaller batches, and have things premeasured ready to mix when you are ready? If you are chucking out batch after batch, the time will be cheaper than all those ingredients. I may be missing something, I've read it a time or two to make sure I understand the problem...

 

[jblaney]

Thanks everyone for your recommendations.

I already soap cool and don't discount wanter too much. I'm done splitting batches and I'll just make two smaller batches. I did it today and all went well.

Todd_in_Minnesota - sounds like you were doing some complex splitting. I've realized there are too many ingredients and too many possible ways I can mess up that I don't have the confidence to try what you were trying. Sorry to hear about your nice smelling grey green disappointment. I have been there several times and I have learned to move on and use it as a learning experience.

 

[DeeAnna]

"...by not weighing out both parts I'm using too much in the first half and not enough in the second...."
"...What I'm thinking is happening is there is evaporation with the lye/water from the heat generated and . ..."

Yep. Evaporation and any weighing error could definitely affect your soap. Let's ignore any weighing error and just look at the error due to evaporation. Picking numbers out of the air, let's say your lye solution was this:

400 g water
200 g NaOH
600 g total solution

And you mixed that up and got, say 20 g of evaporation by the time you were ready to pour the lye solution. (I have no idea if this amount of evaporation is realistic, by the way.)

So now you have 580 g of actual solution. You ~should~ pour half of what you actually have -- 290 g -- to get half of the lye into each batch.

If you work off your original weights, however, you would instead pour 300 g into the first batch -- 10 g more lye solution than you should. That means that batch would get 3.5% more lye than you want it to have.

You would have only have 280 g solution left to pour into the second. That means this batch would get 3.5% less lye than it needs.

Your results seem to be consistent with this trend -- first batch is "okay" and second is soft (=overly superfatted).

Any weighing error would add more skew to the lye in your two soap batches.