Cream goes slightly "grainy" after coming to room temperature

Hello,

First time posting!  I have been working on a light body cream and can't seem to get over one hurdle.  Product mixes well and is creamy, smooth texture until it hits around 20-22C.  If I heat it again it becomes creamy and smooth, but it will return to the grainy clumpy texture at room temperature.  

My ingredients are as follows:
Phase A - Water, propanediol, caffeine, cetearyl glucoside, xantham gum, carbomer, EDTA, phenoxethanol.  

Phase B - caprylic/capric triglyceride, shea butter, coco-caprylate caprate, tocopheryl acetate, dicaprylyl ether, lecithin, glyceryl stearate se, isoamyl cocoate, myrstyl myristate, cetyl alcohol.  

Carbomer is added slowly to water and mixed at 2500 rpms.  Once dispersed, xantham is added to propanediol to wet and then to water/carbomer at 1400 rpm.  The rest of A is added and heated to ~75C.  

B is added after melting shea and brought to ~75C.  

AB are then added and mixed at 2500 rpms for 5 mimutes.  Temp is reduced and at 10 minutes cream is nuetralized.  Product is then mixed at 1400 rpms until reaching room temperature with water bath.  I have tried removing the shea and other room temperature solids from the oil phase with other oils, but get the same texture result.   I have checked the polarities of the lipophillics and they range from low to high polarity.  My oil phase HLB is calculated at 10.6 not including the the ether, and the emulsifiers used have been calculated at 10.6.  Any help, advice, suggestions would be great.  I am not sure if this is a processing error or I am missing something else.  

Comments

  • There's another thread in here somewhere talking about cetyl alcohol crystalizing. The chemist recommended trying out behenyl alcohol instead. 

  • Thanks, I have that (behenyl).  I could give that a go.  Odd, though, since cetyl is used in no many products.  Perhaps a blend of others (cetyl/stearyl/cetearyl/behenyl) may lower the cetyl percentage and reduce the risk. 
  • It is probably the shea butter although since you provided no percentages it's hard to be certain.
    Design of anti-aging creams, gels, and serums; shampoos; and therapeutic cosmetics. In-house label and box design capability.
  • Belassi,

    Thanks for the comment.  I actually tried a variation not using shea, as well as one melting the shea separately before adding and still had the same issue.  I read a decent amount on butters crystallizing as well, so I understand your suggestion.  I am in the process of trying the benehyl alcohol with reduced percentage for cetyl, or I will just omit cetyl, and use cetearyl to get a more varied blend of fatty alcohols.  I will post when I know what that yields.  The percentage of shea is 2%.  Any other thoughts, suggestions would be great.  
  • caffeine is only soluble to 2% in water and probably less in lipids
    Design of anti-aging creams, gels, and serums; shampoos; and therapeutic cosmetics. In-house label and box design capability.
  • Belassi, 

    Nice catch.  I checked the SDS and you're right.  I will reduce that as well and see what happens.  Thanks.
  • Did you try slow mixing for an extended period of time? Like 400 rpm for 3 hours at rt? Some liquid crystal emulsifiers can take a while to form the right lamellar structure. 


  • Update.  Created a fatty alcohol blend, with behenyl as the heavy hitter, dropped caffeine to 1%, and bam--beautiful.  18 hours later, still good.  Thanks for the input!
  • From the picture, your cream has air trapped in it.
    Congratulations on solving the problem! 
  • I tried cetyl alcohol and cetearyl alcohol together in one formula, I never got any problem.  The formula stayed smooth and homogenous for 3 years.  Not grainy.  No separation either.  In that formula, I didn't add any thickener (no Carbopol, no xanthan gum,..etc).  I think it gets grainy, in your case, because you have a really competitive and strong thickener (carbopol) and another thicker (xanthan gum).  These thickeners consumes the amount of batch water your have in their hydration and thickening and don't allow enough free water in the batch to emulsify with oil phase, may be that why you got the grainy appearance when you cool down the batch, but, when it is hot the emulsifiers are already melting, so you may not notice any grainy appearance.  You may try to make the batch with cetearyl alcohol and another emulsifier(s) without any thickener because Cetearyl Alcohol is considered emulsifier, stabilizer, and thickener
    https://www.ulprospector.com/en/na/PersonalCare/search?incival=Cetearyl+Alcohol&sug=1&st=1
    The technique of emulsification is also important.  You may melt the oil phase separately than the water phase.  I think you got the emulsification temp. right, then, when you add the oil phase to the water phase, they should be at the same temp. with high shear mixing for 15 - 20 min. then you may need to cool it down very fast with slowing the shear mixing gradually till low mixing shear at room temp. (Disclaimer: This comment represents my personal idea/opinion which may not be suitable or reliable for all manufacturing setting.  Different Results may occur based on manufacturing setting and some other factors.)
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