Weighing Your Essential Oils for Formulating
Since the airing of my discussion about using weights versus drops when blending or formulating, I have had LOTS of questions. So this will be a short continuation of that talk to help you understand where to get the dilution rates from and how to do it if you still have questions.
If you utilize Robert Tisserand’s Essential Oil Safety book, you will see that most essential oils have recommended dermal maximums. Depending on your oil, the percentage will vary as I mentioned in the video. If you have read the blog I wrote on dilutions versus charts here, I have listed a few examples of essential oils with their recommend maximums for dermal application.
If you do not already have a scale that can accurately measure in grams to the 0.01g, I suggest you see what you can find as there are a few essential oils that will need that low of weight when calculating. If you have one, FANTASTIC!
The first thing you will need to do is find out what the grams to ml conversion is. In order to do this, you will put a graduated cylinder on your scale and tare it to grams. For this exercise we will assume we are using a 30 ml bottle so you will add your carrier to 30 ml.
Since I don’t know what carrier you are using, to make it easy, let's say the carrier weighs 50 grams after filling it to 30 ml in your graduated cylinder. If you take 50g ÷ 30ml =1.67g/ml. That is your gram to ml conversion.
So, if you have already looked up your dermal maximum for your essential oil or created a stock blend, it is really easy to weigh what you need to create your blend with carrier and essential oils. You already know that a 30ml bottle holds about 50 grams of carrier oil based on our first measurement and weight of the carrier oil example.
Let’s assume the essential oil has a recommended dilution at 1%. Of 50g that means 0.5g of your essential oil or blend needs to be added to your 30 ml bottle. You will then weigh 0.5g of your EO or blend into the empty 30ml bottle.
Then you just have to add your carrier oil by filling to a weight of 50g or taring again to add 49.5g.
If you want to add the carrier first instead of the essential oil you can. It would just be at 99% of the 50g (or 49.5g). Then fill with your EO stock blend to 50 g (or 0.5g).
I hope this helps to explain how to more accurately measure and weigh your formulations!