Also called: fragrance flash point
What is flash point in candle making?
In short
Flash point is the lowest temperature at which a liquid gives off enough vapour to ignite near a flame. Suppliers publish it because it governs how a fragrance is classified for shipping, not because it tells you anything about how the candle will perform.
The claim you will see everywhere
A great deal of candle-making advice tells you to let your wax cool below the fragrance oil's flash point before adding it, on the grounds that adding it hotter will "burn off" the scent. This is one of the most widely repeated instructions in the craft. It is also based on a misreading of what flash point measures.
What flash point actually is
Flash point is a safety and transport classification. It identifies the temperature at which a liquid produces enough vapour to ignite in the presence of an ignition source. Its practical purpose is telling a courier how to handle a drum of fragrance oil. It is not a threshold at which the fragrance is destroyed, and nothing about it describes scent degradation.
What would actually degrade a fragrance
Fragrance is lost by evaporation, which is governed by boiling point, a substantially higher temperature than flash point, and one you are not reaching when you stir oil into melted wax. The temperature at which you add fragrance is worth getting right, but for a different reason entirely.
So what temperature should you add it at?
Follow the wax manufacturer's stated figure. The reason that figure exists is binding: the wax needs to be hot enough, and stirred long enough, for the fragrance oil to fully incorporate. Adding fragrance when the wax has cooled too far is the more common real problem, the oil does not disperse evenly and can pool, which gives you inconsistent scent and possible weeping later.
Where the confusion probably comes from
Flash point is one of the few numbers printed on a fragrance oil's specification sheet, and it looks like a limit. Suppliers list it because they are legally required to classify the liquid for transport, but a number sitting on a spec sheet next to temperatures you genuinely do care about, melt point, pour temperature, invites being read as another one of those.
Once the idea took hold it spread the way most craft folklore spreads: it is easy to state, hard to test at home, and following it does no visible harm. A maker who adds fragrance at a lower temperature and gets a good candle has no reason to question it.
The useful takeaway: if your candle does not smell strong enough, flash point is not your culprit. Look at the fragrance load against the wax's rated maximum, whether the candle had long enough to cure, and, most often, whether the wick is big enough to make a full melt pool.
Good to know
Questions people actually ask
Is it dangerous to heat fragrance oil above its flash point?
Treat it with respect: it means vapour could ignite if it met an open flame. That is an argument for keeping flames away from your melting setup and not overheating wax, which are good practices regardless. It is not an argument that the scent is destroyed.
Why do so many suppliers repeat the flash point advice?
It has been passed along as received wisdom for a long time, and it sounds plausible, flash point is a number printed right there on the spec sheet, so it gets read as a performance limit. The specification is real; the interpretation is not.
What actually makes a candle smell stronger?
A fragrance load at the wax's rated maximum, a full cure before burning, and a wick large enough to melt right out to the container wall. Of those, the wick is the one most often wrong.
Blend a scent with help
Candle Craft sessions handle the temperatures and the chemistry. You get to concentrate on the part that matters, what it smells like.