[geepee]

Is this happening to one of your formulas? If so:

What are your ingredients and phases?
What is your method?

Then I can see what you might be missing in your formula and help from there.

[geepee]

pH needs to be around 3.75 and final pH when adding all of my glycolic acid was around 2.8 before adjustment with caustic, it got thicker at a higher pH than 2.8 (I did not measure) but I need to add 12% glycolic acid so cannot just stop adding acid when it is thick…

[geepee]

So! I tried the above (excluding changing the SCMT, i still used the pureact), added everything excl. salt, glycolic and caustic and started off adding salt - no change to viscosity. So then i added glycolic and it THICKENED!! but then when i added caustic it thinned 🙁 so I think the formula doesn’t like too much pH change down and then back up.
Should I try adding caustic first, then glycolic and salt last and making viscosity?
I just worry when scaling up the pH will be harder to predict as to how much caustic to add etc.
Thoughts?

• This reply was modified 1 year ago by  geepee.

[geepee]

So, I tried adding caustic first (not ideal for manufacturing :/ ), remainder of my ingredients, then glycolic and salt last and making viscosity, salt had no effect on viscosity but pH was exactly where I wanted it at around 3.75.
I honesty don’t know where to go from here… I can get pH right but can’t get it to gel!!!

[geepee]

Great thank you!
So from what you are both saying…
- Potentially try another SCMT supplier
- Add glycolic acid last and slowly once i have made viscosity and then adjust with KOH to be in spec
- Increase SCMT active percentage to 3x that of betaine - my SCMT is 20% active, CAPB is 30%, so try 30% pureact and 6.5% CAPB30?
- Add my Decyl glucoside with fragrance and oils at the end?

[geepee]

Thank you! 
I have solved it now 🙂

[geepee]

Thank you, I was feeling that this might be the issue in regards to the glyceryl stearate citrate.  
What if I:

• Added 0.5% xanthan - help thicken the water phase
• Scrapped GSC and swapped it for another nonionic emulsifier with an hlb ~9 at 5% and took sorbitan olivate down to 2%
• HLB drops to ~7.5

Do you think the higher HLB emulsifier would be better at holding all of the lipid at the higher temp?

100% accelerated stability is frustrating, it’s passed 6 rounds of freeze thaw but when you see the results from the oven it’s disheartening and makes me question the stability of the formula when I am sure it is fine.

Should i be worried about only emulsifying in the cool down phase?  Is it an issue if it all comes together in the end? - I’m completely stumped here as i have never experienced this.  

[geepee]

60C is too hot, most stability tests are done at 40C