Adventures in Spritz formulating – The Method Matters.
When I’m not creating new stuff I’m working on improving or trouble shooting old stuff like the spritzer shown here.
This project came back up for review after some manufactured stock was looking a little worse for wear 9 months into the shelf life. This can happen and is one of the reasons that I suggest that clients stick to small batches for the first year of launching a new formula unless they are going to do accelerated stability testing and preservative efficacy testing – neither of these things are mandatory in Australia.
You might well think that as a consultant I should KNOW what is stable and KNOW what preservative system will hold up in each product before the formula is agreed upon but that is often not the case. While experience and time are great teachers as every customer has their own particular wish list of actives, excipients, price point and packaging the cold hard reality is that every time we formulate, we formulate a unique product to suit that clients brief – something brand new! Of course we do use our knowledge and experience to iron out the obvious but if time has taught me anything it’s that doing chemistry with natural ingredients can feel like a a semi-educated gamble. Essential oil chemistry varies from batch to batch affecting solubility and smell, ditto with herbal extracts.
The main issue with the above is solubility – a good spritzer should be crystal clear and this one isn’t. To be honest I think what happened here is that the solubiliser needed to be added at about 0.3% more than my formula specified but because I’d only made it on a small-scale I hadn’t picked that up and recorded it. That said, the sample in the middle made at the same time as the sample on the left hand side shows me that there’s more to it than just chemistry – physics also plays a part.
I made all three of the above a month ago and have stored them in a 40C oven to see what’s what. That would be equivalent to 4 months real-time which is not really long enough to pass as a shelf life but is usually long enough to uncover nasty problems like this. And it did!
The sample on the far left is the original formula made via a non-optimised but fairly standard manufacturing process. It has completely separated and is now useless.
The sample in the middle was made with an optimised process focusing on maximising the solubility of each component and mixing in a specific way. This sample, while not crystal clear is still good and to be honest, in an opaque bottle it would be able to be sold without any issues. This proves that while the original formula wasn’t perfect it does work – granted we’d need another few months stability before we could completely call it a win.
The third sample is one that I made to the same base formula but with an alternative preservative. Why? Well I learned something interesting while fiddling with this formula- that the preservative I’d originally chosen (as it met the brief and seemed to work) was a big part of the reason for the haze. The haze did go when an additional 0.3% of solubiliser was added but changing the preservative while keeping the solubiliser at the original level worked even better! It’s amazing what you find out when you fiddle around…..
Anyway, this whole ‘can we just have another look at this’ project has taught me a couple of great lessons and for that I’m grateful. This spritz was quite different to others I’ve made having heaps of actives in it plus some tricky to work with essential oil and a strict preservative requirement. I’d missed all of this fun when I first made the product because I fluked it and over-shot the solubiliser just enough to bi-pass this completely – I’ll definitely take more care with my measurements next time and will run at least three scale up batches before going to manufacturing.
So my take home message from this project is that when making a spritzer the method of manufacture matters quite a bit more than I’d previously given it credit for and in this case it has made the difference between a saleable and a dump-able product.
As much as I don’t like things to go wrong you’ve got to love a good problem to get your teeth stuck into.
I have learned so much from this little beauty and hopefully now, so have you!