It is a term used in pharmaceuticals and food manufacture mainly.  It is an abbreviation for Quantum satis and simply means ‘Add as much of this ingredient as is needed to achieve the desired result, but not more’.  So if we take the example below

 

INGREDIENT %     
WATER QS
EMULSIFIER 4
STABILISER 2
OIL 15
PRESERVATIVE QS
FRAGRANCE QS

What you would need to do when deciding what to put in place of the ‘qs’ is read the guidelines for the maximum use rate.  With most ingredients you only add up to the maximum allowable amount.  When it comes to preservatives, normally you should try and use the minimum recommended amount and then adjust upwards if need be following your tests – this is because all preservatives are potential irritants so you should use the minimum amount to keep your product free of germs.   Similarly with a perfume, you only need to use enough to give the desired scent.  With water, that can be used up to 100% but for obvious reasons, you put in enough water to the formula to make the whole formula calculate  to 100%.  Now it may not stop there, you may have to make an educated guess if you are not sure about an ingredient.  I got a sample of a fragrance and the supplier suggested the use rate as 1-2% – I decided to put 1.5% of said fragrance which was way too much and in the next batch I knew to reduce significantly, in this case to 0.2%.   In sum, what you replace your ‘QS’ with may change after making the physical product and doing your tests.

So there you go, that was pretty straightforward!

Today I was inspired by Eeting to make a body cream.  She told me that she had decided to recreate montanov 68 (the blend of cetearyl glucoside and cetearyl alcohol)  to use in a cream.  She was really happy with the results and especially that there was no soapy texture that you normally get with the majority of natural or organic certified emulsifiers and significantly less than you get with Montanov 68.  So I thought I would try it and honestly I was not disappointed.  I used over 20% for the oil phase as with lamellar crystals, to get a thick cream you need >20%.  I stabilised the water phase with xanthan gum.  Other ingredients I used were;

Jojoba oil – technically a wax, this light oil has a fairly long shelf life and nice compatibility with most skin types.

Sweet almond oil – this is a more oily oil – it adds a nice slip to the cream and allows for a little more play time

bis-2-Diglyceryl Polyacyladipate – this is very very similar in texture and stickiness to lanolin.  I mean it is very sticky and occulusive and moisturising without the smell.  I will blog briefly about this later.

cetearyl alcohol – we need some fatty acids in here – this acts as a co emulsifier as well as a thickening agent and will help create the lamellar structure.

Sunflower seed oil – this a a nice addition as it is quite a dry oil.

Baobab oil – rich in a multitude of lovely vitamines and minerals.

Isoamyl laurate – this esterified oil is a an extremely light addition to any product, a natural alternative to cyclomethicone. It is a polar oil that disappears fast on the skin adding to an improved skin feel.

Frankincense, Rose and Rose geranium are lovely for dry and dehydrated skin.

The cream I made today has the following ingredient list not in any particular order;

Aqua,Simmondsia chinensis (Jojoba) seed oil,    Prunus amygdalus dulcis (Sweet almond) oil, cetearyl glucoside,  bis-2-Diglyceryl Polyacyladipate (vegan lanolin) ,  Helianthus annuus (sunflower) seed oil, cetearyl alcoohol, Isoamyl laurate, Adansonia digitata (Baobab) oil, glycerin, aqua,  xanthan gum, Benzyl Alcohol, Salicylic Acid, Glycerin, Sorbic Acid, rosa centifolia, boswellia carterii (frankincense) oil, pelargonium graveolens (geranium) oil, rosmarinus officinalis (rosemary) extract. 

I am going to do some quick tests to see that it is stable and probably add it to our formulas.

Bex

xoxo