Most of us, when we catch a whiff of something beautiful, are thinking less of volatile molecules and more of following that scent to the ends of the world.
But fragrance is something special, because the scent of a candle is one of its most important characteristics. We choose a fragrance because it reminds us of a special memory, or it makes us feel relaxed or even energized. Whatever the imparted effect, though, it all comes from one place: chemistry. And the longest-lasting effect we achieve with our scent is in the dry-down stage.
This makes dry-down an important consideration in the choice of a fragrance. So what is this “dry-down” and how does it affect the candle as its burning?
It’s pretty simple, really. Some smells stay around longer than others.
As with wine, cheese or music, greatness in fragrance often means complexity. If you regularly burn candles, it should come as no surprise that your favorite scent unfolds in stages. The way a candle smells immediately after lighting it, and then 20 minutes later, and then 40 minutes later can be quite different. This is by design. The people who created that scent chose its ingredients not only by their individual and combined aromas but also based on their relative evaporation rates.
The changing character of a fragrance comes from the varying volatility of scent molecules. When you light a candle, the first thing you smell is the combined effect of all of the scents in the product. Then, as some of those scent molecules evaporate and others stick around, the fragrance starts changing. Eventually, what you’re left with is the scent of the longest-lasting, or least volatile, of the scent molecules included in your perfume- and this final stage is called the dry-down.
To be more specific, the scent of a candle unfolds like this:
· Top notes: This is what you smell when you first light the candle. It is the result of all of the scent ingredients blended together. This scent lasts only a short time.
· Middle notes: As the most volatile of the scent molecules evaporate, the middle notes arise. This scent is considered the “heart” of the fragrance.
· Bass notes: When the middle notes dissipate, the base notes take over. This is the dry-down period, and this final fragrance is said to reveal the “body” of the perfume—its true scent. This scent lasts for the life of the candle.
Although a scent is designed by perfumers to unfold in a particular manner, it is not always a uniform evolution. This is where things get interesting, making everyone’s fragrance experience a little different!