Smell is one of the main reasons we like candles.  I love the rush of memories that come flooding back in when I stumble on an old scent.  Our sense of smell is wondrous and powerful, connected to a deep network of memories that are sometimes locked behind a scent, otherwise inaccessible.

The Science behind smells, emotions, and memory

Contrary to popular belief, there are far more senses than the five you’re taught in school (balance, space, movement, pain, just to name a few), but for argument’s sake we’ll stick with the popular ones: Sight, Touch, Taste, Hearing, and Smell.

Your sense of smell has the literal shortest path to the part of the brain that processes emotions.  The amygdala.  The amygdala knows what the heck is going on with a smell because a different part of your brain “translates” the smell into something it can understand.  The translator is called the olfactory bulb.  Your brain takes more time to analyze other inputs, so smells are really the most raw form of input when it comes to emotional connections.

Smells also come in such a variety that we don’t “get used” to them as easily as other things.  If you’re processing a strong emotion during a time that you’re also experiencing a smell you don’t interact with regularly, it’s much more likely that experiencing that smell later will invoke that memory.  It’s why a lot of smell-conjured memories are things that took place outside of our regular routine – those smells didn’t become so familiar that we couldn’t distinguish them.  The brain is magnificent! Smell is so tightly related to emotions and memories that it’s not surprising how abundant scented products are. In fact, this relationship is continuously used by scientists to tackle memory-related illnesses like Alzheimer’s.

What is a scent?

Michael Edwards was born in 1943 in a small, unassuming African country known today as Malawi.  41 years later he published The Fragrance Manual to assist retailers in understanding and promoting different scent lines.  This book became a guide for the fragrance industry and is still widely used and updated today.  Edwards gave a structure to the complicated world of smell, saying the theory that every smell belongs to one of four main categories:

Floral

Flowery smells like roses or lilacs.  Most people can easily classify floral scents.  This is traditionally more feminine.

Oriental

Warm, spicy scents that are traditionally found in the Eastern World.  Think cinnamon, amber or vanilla.

Woody

Earthy notes like cedar, leather, or peat.  Typically more masculine than not.

Fresh

Here you’ll find lighter fragrance notes like rain, linen, or citrus.

The categories are used broadly by the perfume industry as the starting point for classifying a smell.  But what exactly is a smell when it comes to candles? Fragrances are really just a combination of different notes, just like whiskey, wine or perfume.

Fragrance notes encompass the entire experience of a fragrance.  The manner in which it is used varies among industries, but the concept is the same whether we’re discussing perfumes, tastes, or candles.  A given scent may be largely called one of the four categories, but still have a complex personality. The actual smell is more of a journey than a destination as you can see by the fragrance note pyramid below.

Your favorite smells are often a good and complementary combination of different note categories that suit your amygdala.  When someone describes a scent or fragrance as “complicated”, they may be talking about the different combinations of notes throughout the lifetime of the fragrance.

CandleScience is a widely popular distributor of fragrance oils for candles.  On their fragrance oil Amber and Driftwood page, they call out the note profile:

The top notes are generally classified as Fresh, which isn’t surprising.  Most scents categorized as fresh are much lighter and evaporate more quickly, which is a primary characteristic of the top note in a fragrance.  The middle and base notes in Amber and Driftwood are generally Woody with a touch of Oriental (in the Amber and arguably the Powder).

What’s in a fragrance?

The experts in this particular field, people like Michael Edwards, are far and few between.  There aren’t many Master Perfumers. People at or near that level have an extensive background in the fragrance industry and typically have formal education in Chemistry.  Much like a Sommelier, there are levels to this sh*t. The other interesting thing about fragrances is how protected they are.

In the United States, the U.S. Food & Drug Administration requires cosmetics to have an ingredient list on its packaging.  Giving away all the fragrance ingredients could be very harmful to a company so the FDA allows companies to file for “Trade Secrets” with those items and instead let them label the ingredient simply as “fragrance”.  And although it might be slightly frightening to not really know what’s in a cosmetic product or fragrance oil, it doesn’t mean skirting safety laws and regulations.  It only takes one viral social media post to put pressure on a company (or even trigger legal action) if they take part in any funny business.

But in general, most fragrance oils purchased for use in candles contain some combination of:

• Aromatic chemicals (produced in a lab to provide a characteristic scent)
• Essential oils (extracted from nature… plants mostly)
• Chemical reaction agents (solvents, diluents, etc)
• Synthetic compounds (alcohol, carrier oils)

It’s just chemistry at that point, which any high level perfumer might have a strong grasp on already!

Synthetic vs Essential oils

There are a lot of reasons people may be attracted to essential oils for building a fragrance.  There’s nothing inherently wrong with essential oils, only the confusion about what they claim to do.  That’s up to you to debunk or understand, and I don’t have any advice to offer on the health-related claims for using essential oils.

What we do know is that synthetic fragrance oils purchased from major suppliers in the United States are absolutely safe to use and are constantly improved to meet the latest regulations or guidelines around their use and distributions (Research Institute For Fragrance Materials and The International Fragrance Organization).  Essential oils are normally found to offer very little performance in candles during burn time (hot throw) despite their occasional strength at rest (cold throw).  They aren’t dangerous but they might not be giving off the scent you desire from a candle.