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Crystallisation in Gel
Hi, I made an aloe vera gel about 6 months ago, put it aside so see if preserves well. I looked back at it yesterday and found crystals had formed inside! At least I think they are crystals because the shape of the particles look a bit like snowflakes. You can see some photos from this link:
Would anyone have any ideas what went wrong?Your help is greatly appreciated! -
21 Replies
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what materials are in this gel, and what levels are they included at?
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Its just a very simple carbomer gel….
water 95.5%carbomer 1%aloe vera 1%liquid germall plus 0.5%propylene glycol 2%TEA for neutralisationI didn’t use de-ionised water, just RO water from my home filtering system.Without aloe vera it seems fine….so I’m thinking its the aloe. -
Not likely to be the aloe. I have gels with up to 40% aloe vera content with no problem like that. More likely to be carbomer that failed to disperse/neutralise, eg “fish eyes”.
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could you explain a little more about this please?
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Looks like your Preservative components are crystallizing.
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Hard to say without the sample in front of me, but if I had to guess I would have to suspect the carbomer as the issue. I have seen that “tapioca” pudding-like fish eye formation in the past. I am sure many of us have also in Production.
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Try the same recipe with Ultrez-20 and see if it happens again. My bet is not.
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Mark, if I send the sample to you would you be able to do some analysis work for me??
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That would be a waste of time. Honestly it is something you can trouble shoot yourself.
What grade of Carbomer did you use?
How did you hydrate the carbomer? Do you have homogenization? If not, what is your highest available shear?
Lubrizol has volumes of helpful documents online that will help when working with carbomers. Also they have many different grades of Carbomers. Carbopol Ulrez 21 is excellent for making clear gels and very easy to work with.
If changing the carbomer doesn’t solve it you can look further. What was the final pH? Did it vary over the 6 month period? Has the viscosity changed?
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ok…I’ll give it my shot…just very very beginner here working from home kitchen! If you take me step by step hope I work it out.
This batch was made by normal mixing using KitchenAid slow-medium speed. Basically I leave it overnight to hydrate and don’t stir it around too much afterwards.No, I don’t have a homogeniser …I just bought an overhead mixer VMI brand and still experimenting with it so I can go to high shears if that’s needed. Haven’t bought a homogeniser head yet, just have a “normal” blade.I used Sodium Carbomer, its pre-neutralised and can be bought online from http://www.lotioncrafters.com. I need to look for a local supplier where I can by Carbopol from.Unfortunately six months ago I didn’t take the pH ….viscosity seems not much change.I did some search about the “fish eye” effect, I understand it seems like a mixing issue? The formations in my gel look more like crystals and its only observed after I left it for some time. At the time of bottling it all seemed quite “clear”.really appreciate the help here! -
@yq1:
It would appear that you did not follow the use directions on the Sodium Carbomer which is pre-hydrated and does not need to be neutralized and is recommended for use at 0.2%. So, you added TEA which really jacked up the pH of your formulation when it was not necessary and since you did not measure pH, you have no idea about basic parameters of your concoction.Throw it away and start over following use directions and measure relevant parameters. -
When I add aloe to the water the solution becomes acidic so I would need to add TEA to bring the pH up to around 7 so that it can gels.will try again when I can get hold of some Ultrez 21
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aloe doesn’t make a formula acidic. I have never noticed any discernible change in pH adding even large aloe vera concentrations.
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This is telling me that there is something very odd going on in your Aloe. Are you using a concentrated powder or a liquid?
Remember, Acid + Base = Salt, so the chances are high that whatever is crystallizing out is the TEA-salt of the chemical that is making your Aloe acidic. Aloe by itself is neutral pH. -
@BobZ:
I was thinking the same thing. Try adding a chelating agent, particularly if you are using a powder aloe concentrate.I also noted that the OP claimed that TEA was needed to raise the pH, but didn’t take a pH measurement. So, just how is it that you knew when to stop adding TEA? Does not make sense. -
I used powdered Aloe vera (200x). Just measure pH at 1% in solution it is 4.5! Bobz, I think this could be the problem, Acid + Base = Salt, seems to make sense!
After adding aloe, I added TEA until I reached pH7 (that’s the only time I measured the pH) but didn’t measure pH of final product after adding carbomer.If I add EDTA, I suppose no need to change to Ultrez 20? Or maybe I should anyway?Finally, how can I know that EDTA works?? Really don’t want to wait 6 months before knowing! Is there any kind of tests I can do to find out?Thanks everyone! I think we are getting to the bottom of this!! -
@yq1:
(1) With Aloe Vera Powder (200X), you only need to add 0.5% to effectively have Aloe Vera Juice equivalent.(2) Since Aloe Vera Powder is a real stew of electrolytes and individual components, first add your chelating agent (0.3% should be fine) to water and mix thoroughly. Heat the water up to 77C and add the Aloe Vera Powder and Propylene Glycol and hold the temperature for 20 minutes.(3) Cool down to 30C and check the pH.(4) Sprinkle the carbomer onto the water while stirring and allow the carbomer to hydrate for 30 minutes or so. If you’re using the Sodium Carbomer, mind the recommended use amount … adding more can just cause problems … (More is not necessarily better when you’re formulating)(5) Add the Liquid Germall.(6) If you are using a carbomer other than the pre-neturalized Sodium Carbomer, slowly add the TEA (personally, I prefer using Sodium Lactate as opposed to TEA, but just my preference) while stirring and monitoring the pH until you hit the right pH for the carbomer to gel.No, there is no way to definitively know if the EDTA helps solve the problem until time has passed that I am aware of. -
Thanks so much MarkBroussard for the step-by-step!!
Is there a reason for step 2, heating and holding? Usually the aloe just dissolves as I stir it and there is no need to add heat. Or is the heating for the chelating agent to work better?Why is Sodium Lactate your preference over TEA? -
Step 2 is standard operating procedure, sterilisation.
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Yes, first heating ensures complete solubilization of your chelating agent and components in the Aloe Vera Powder. Second, as Belassi pointed out, unless you are certain that your Aloe Vera Powder has been irradiated, it is probably chock full of microbes, so this is a solubilization and sterilization step.
Sodium Lactate because as the sodium salt of lactic acid it is an excellent moisturizer. TEA does not really provide any skin benefit and you have the perception of the nitrosamines issue. So, I prefer to use a multifunctional ingredients as opposed to a single purpose ingredient with a marketing concern. -
Thanks everyone for the explanations!! Learnt a lot here! Will give it a try and hope things work out this time!
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