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Specific gravity is a fancy way to describe density, and gives us a good way to figure out how much something weighs when it fills a certain space.
Makes a lot of sense since we measure out wax by weight in an attempt to fill a volume.
Weight and volume are tied together by density – if you know two of them, you can always find the third.
Density is our behind-the-scenes actor making sure the formula we use to measure wax is accurate and precise.
More on that in a second.
What is specific gravity and how does it relate to density?
Don’t let the words fool you.
Even though they sound complicated, they aren’t. Specific gravity describes the density of something compared to water.
It’s just a relative number.
Water always has a specific gravity of 1.0.
If you find something with a specific gravity of 2.0, that means it’s twice as dense as water (it would fill half the space as water but weigh the same).
Remember, objects and supplies that are really dense seem to be really heavy without taking up much space.
Candle wax specific gravity ranges from 0.80 up to 0.98, depending on the wax blend included in the formula. A higher specific gravity means more wax is required to fill a space.
Fragrance oils have an even larger range, which explains why some bottles from suppliers contain less than others: they sell by weight, not volume.
Oils with a higher specific gravity are more dense and fill less space than a fragrance with more top notes and a lower specific gravity.
A fragrance oil with a high specific gravity will fill less of a bottle than a lower specific gravity but weigh the exact same.
So how can you use this concept for candle making?
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