Fragrance Oils - What you need to know
Welcome in the wonderfully scented world of fragrance oils!
These synthetic oils are probably the best and less expensive ways to add scent to your candles. Furthermore, they offer and almost endless choice of available scents.
But there are several things you must know in order to make good use of fragrance oils.
By its chemical composition, paraffin is very close to oil. Just as it happens with oil, if you happen to pour water in your double-boiler full of liquefied paraffin, water will go directly on the bottom of the pan and paraffin will float on it (another reason why it would be very stupid to try and put off an oil fire - or paraffin fire - with water).
Experience will show you that, whenever you see some kind of big bubble rolling on the bottom of your double-boiler, it's a drip of water that felt into your paraffin.
You've got it by now: it would be useless to try and use a water-based or alcohol-based perfume in paraffin. Birds of a feather flock together: the only solution is to use oil-based scents.
Proportions to use
If you take a look at websites that sell handmade candles, you will often notice expressions like "triple scented candles".
This means that the candlemaker used three times the industry standard. This standard is 0.5 oz of fragrance oil per pound (453 grams) of paraffin.
Thus, in the case of our "triple scented candles", 1.5 oz (42.5 grams) of fragrance oil per pound of wax were used.
That's a lot and it's about all that paraffin can take (3% volume of oil is considered a maximum).
If you use more than 3% oil, your candle could be covered in "snowflakes" (this is also called mottling) under its surface. Actually, as this "mottled" effect can be quite pretty, it is often willingly achieved. If achieving the mottled effect is your intention, you are encouraged to use mineral oil, which is much less expensive than your precious fragrance oils.
Of course, too much oil might result in a "sweating" or "bleeding" candle, with oil coming out from everywhere! It this ever happens, it's not desperate yet: wipe your candle with paper towels during a few days until the excess oil is gone. When the sweating has stopped, your candle should be ok to burn.
Every oil has a Flash Point (FP), in other words a temerature above which it will catch fire. This applies to fragrance oils as well!
Furthermore, fragrance oils often contain more than 50 different chemical components. This leads to widely variable Flash Points (not all fragrance oils share the same Flash point, which doesn't exactly make it easier).
Black cherry - FP: 130°F (54,5°C)
Fresh Orange juice - FP: 165°F (73,9°C)
Island Tango - FP: 195°F (90,5°C)
Water Blossom Ivy - FP: 210°F (98,9°C)
Interesting differences, isn't it?
So what will happen if you add fragrance oil with a FP of 130°F in paraffin whose temperature is 190°F
Nothing. It will not catch fire because the proportion of fragrance oil is so small compared to that of paraffin and that the Flash point of this paraffin is much higher.
BUT your fragrance oil will be "burned"; in other words, its chemical structure (and its scent) will be deteriorated. In the best of cases, you'll get no scent at all but if you're out of luck, it might very well stink!
You see where I'm heading: it is essential to know the Flash point of every fragrance oil you will use.
This information should be mentionned on the label but, unfortunately, it's seldom the case. You should be able to obtain the information from your retailer, especially if he has a website available (if you bought your fragrance oils online and there was no mention of the Flash point, you will probably have a hard time getting the information).
Know that the retailer MUST be able, at your request, to deliver this important information. If they can't or won't: just never buy from them again. Not only is this a sign that they're not serious in business, they're also gambling with your safety.
In an ideal world, every fragrance oil has its own MSDS sheet (Material Safety Data Sheet) where every characteristic you need to be aware of is mentionned.
Click the icon on the left to see a sample MSDS sheet.
Thanks a lot to Lis of Longwyck Candle Works for allowing me to use one of their MSDS sheets (available for every fragrance oil they sell)
If it's full of uninteresting data, a few points should be noted:
Solubility in water: insoluble (well yes, it's an oil)
Flash Point (FP): 150°F (that what's we wanted to know)
If your intention is to make gel candles, there's another thing you'll need to take into account: the polarity of fragrance oils.
Please read the article titled Fragrance Oils and candle gel for more information on this topic.
Fragrance oils can reproduce any existing - or non-existing - scent