Let Me Just Make a Note of That
I take copious notes on every product I develop. I write pretty much everything down: ideas, thoughts, bits of 'AHA!' information about a certain ingredient, and of course the formulas themselves (every version), complete with any tweaks made to ingredient amounts (or if it came from a new/different supplier), production date, how many gr and ml the total batch was, what the PH value was (and whether it was different from last time), whether the formula looks like a winner or a dud, what kind of container was used, how the texture felt, product smelled, etc etc etc.
This makes for a lot of notes.
What's worse, I never throw anything out.
I write as I am formulating* a product, make additional notes as I am producing it, and after the production equipment is packed away, copy (in legible writing) the collated info to my current production notebook.
Over the years, I have devised a system where the 'succes formulas' are copied into 'succes notebooks' (with different self-created icons so I can trace back to the product's beginnings).
I continue to take notes in the new notebook as a formula is customized for someone, I want to try an additional or different ingredient, or a different batch amount is made.
Occasionally, I will go back over my old production notes to trace how a certain ingredient has behaved under different uses, formulas or batches. Guess who inevitably gets sidetracked and is suddenly just reading everything?
It's a lot like getting caught up in an old diary. Ideas are reassessed, old faults (and successes) cause a giggle or two, I will suddenly be inspired to re-try an old formula in a different way, and overall it's a pleasant walk down memory lane.
After several years of meaning to collect all of my 'finished' formulas into some kind of format that is easier and less time consuming to navigate (read, a smart, electronic format where a search function could be applied), I have decided to quit beating myself up over it and just keep taking notes.
In transferring everything to electronic version, I would lose 'the coffee stain on that page' or 'the green ink from the pen I was using the summer my mom stayed with us', and the whole diary experience would disappear. Besides, the formulas are constantly evolving, so I will still need to take notes.
*Formulating is the cosmetics-maker's way of saying 'creating the recipe'