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shampoo stability
Our coffee and licorice shampoo is very popular but I am having trouble with repeat batches. It’s difficult to get the right viscosity and maintain it. This is being caused by the licorice root extract (12% actives) - I think. It’s a perfectly ordinary anionic shampoo:
brewed coffee 71.7%
Plantaren APB 17%
CAPB 5%
EZ Pearl 3%
Sodium benzoate 0.4%
Potassium sorbate 0.4%
licorice powder 1.5%
citric acid Q/S pH = 5 (approx 1%)Root licorice contains:
glycosides called glycyrrhizin (about 7%) and glycyrrhizinic acid, triterpenoid glycosides (saponins), flavonoids(including liquiritigetol) and isoflavonoids, bitter principle (glycyrmarin), volatile oil, chalcones, coumarins, amino acids, amines (choline, betaine, asparagine), oestrogenic substances (including beta-sitosterol), glucose and sucrose (5-15% sugars), starch, tannins (trace), gums, wax.Last time, I tried adding salt, the viscosity got worse.
Added more CAPB: little effect.
I’m wondering if the benzoate/sorbate/citric is pushing it past the salt curve maximum and down the other side, OR if something in the licorice root is really messing things up. Or both? What to try? -
11 Replies
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Well, you could do a knock-out experiment, or even a with- and without- batch to see if it really is the licorice powder.
You could also do a salt curve analysis to figure out where you are on the salt curve. You may be over or maybe not.
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Oh I am pretty sure it’s the licorice. Hmm… I don’t need to adjust the pH much on the non-licorice version; the coffee version alone measured 6.1 on my meter prior to adjustment. Citric acid is an electrolyte, it’s similar to adding salt isn’t it? And I have 1% in there… I tried adding ammonium chloride to see if it would thicken and it had zero effect. (APB is an ammonium-based blend)
- maybe I’ve got too much licorice in there. Yeah. I’ll reduce it to 0.5% and run a 1Kg test batch. -
How consistent are the batch to batch properties of the “brewed coffee”? Considering it makes up the major part (71.7%) of the product, I think this may well have a profound effect on the properties of your shampoo.
Do you have any quality control procedures on the coffee - before or after brewing? Assuming it is roasted coffee the degree of roasting could easily affect the amount of extractables, in turn affecting the composition and concentration of the brew. Are the coffee beans of the same strain of coffee plant each time? Are they from the same harvest? Are they from the same supplier?
With so many variables it is very feasible that one or other, or more, will affect the properties of the final product.
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I used the same batch of coffee and the same amount, but that’s as far as it goes! Probably this is why you don’t see commercial versions…
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Was the coffee prepared in the same manner each time? If you made the coffee in bulk and saved for different batches, was it adequately protected from microbial attack/other decomposition (hydrolysis of one or other component)?
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I make it fresh each time.
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bELASSI THE ANSWER TO YOUR PROBLEMS IS NAMED CARBOPOL AQUA 1
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@fletland: no way! I don’t own a vacuum mixing and filling line, and I’m not having my shampoo looking like cheap hair gel full of bubbles.
Seems to be the salt curve problem. I need to use a fair bit of citric acid which is an electrolyte to get the pH=5. I reduced the licorice content which improved the situation somewhat. Adding more betaine doesn’t work, probably because betaine has a high salt content. Increasing the salt-sensitive primary surfactant might be my best bet? -
Belassi, i dont know why you hate carbopol aqua, this product solve some of the problems you mentioned above, ok lets do it to your way, try with this:
1.- citric acid needs to be inserted in water at the beggining of the proces
2.- identified what sustance decreased viscosity, and when you add this one to your batch joined with capb, you will note it dont break shampoo chain viscosity
3.- peg 12 dimethicone will give you an awesome conditioning and end viscosityi hope this is good for you
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I note that Plantaren APB is a mixture of ALES and ALS. I have never used ammonium neutralised detergents from choice but, whenever I have used them I’ve found that NaCl to adjust viscosity caused the system to collapse. This was corrected by avoiding alkali metal salts and using NH4Cl in their stead.
You may find also, that using pro rata amounts of sorbic acid and benzoic acid rather than the salts would help. At that level, I expect them to dissolve in the detergent base.
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Thanks for all the help. I do have ammonium chloride. I’ll see if PEG12 dimethicone is available here.
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