Soy Candle Fragrance Throw
Fragrance throw is the name given to the release of scent from a candle and is classified as cold throw and hot throw.
Achieving the perfect fragrance throw is part of the holy grail of candle-making. In this blog we share our years of experience in the soy candle industry to help you in your pursuit of the perfect fragrance throw!
Cold throw is the release of fragrance when the candle is at room temperature, unlit, and therefore the wax is solid. Hot throw is the release of fragrance when the candle is burning. Most people have experienced the difference between cold throw and hot throw – mainly in terms of strength, but also sometimes in terms of the character of the scent. We believe that great cold and hot throw are essential to a good product – you need a good cold throw, especially when your candles are on display unlit, and you need the candle to perform equally well when burning to keep your customers coming back for more!
The science behind fragrance throw is essentially the same for cold and hot throw, but the conditions of a lit and unlit candle are different, and like anything, different conditions can lead to different results. The fragrance in the candle has to evaporate for us to smell it. The molecules that make up the fragrance evaporate into the air and make their way to our noses where the complicated system of receptors and nerves sends a signal to the brain, which we interpret as the smell. Put simply, the more fragrance molecules that evaporate from the candle and end up in our nose, the stronger the sensation of the smell. It follows, therefore, that when the candle is warmer, more molecules will evaporate and end up triggering the smell – this is why we usually see a stronger hot throw.
There are other things at work too. Every fragrance is made up of lots of different chemicals, each of which contribute something to the overall scent, called notes. We divide a fragrance into top notes, middle notes and base notes.
Top notes are the ones that we smell immediately, and the reason for this is because the molecules that make up these parts of the scent usually have a low evaporation point – this means they evaporate quickly and easily – so they make their way to the nose first, and at lower temperatures (cold throw and early stages of burning) there’s usually more of the top notes that have evaporated into the air so these notes are dominant. Usually it’s light, sweet, fruity scents that are in this category.
Mid notes are a little heavier – they take a little longer to evaporate and so they come out next.
Then we have the heavier base notes – think woody, musky notes that underpin the fragrance and form the lasting scent character. These notes may not be detectable straight away.
What can you do to improve the candle fragrance throw?
The makeup of the candle and the way it’s made can have a big impact on fragrance throw.
All of our fragrances are designed and tested to work optimally with our waxes. Be careful when you buy fragrance because not all fragrances are created equal, they may share the same beautiful sounding name but cheaper fragrances are cheaper for a reason. They are often ‘watered down’ versions…meaning they contain more base oil and less actual fragrance notes. Cheaper fragrances usually contain phthalates, a rather nasty little chemical which you don’t really want in your natural soy candle!
If you want to have the best shot at obtaining optimal fragrance throw, start with high quality fragrance oils that are phthlate free and designed for use in soy candles.
Fragrance load. It’s very important to pay attention to the recommended fragrance load for each wax type, fragrance load simply means how much fragrance you can “load” into the wax. The chemistry of the waxes means that they will hold a particular level of fragrance oil best. Overloading a wax with a higher fragrance percentage than recommended can actually make the fragrance throw worse as the wax cannot hold all the oil which can lead to the sooting, leaching and burning issues mentioned earlier. We recommend using between 6% and 10% fragrance with most soy waxes.
You can find out more about how to calculate fragrance load and ingredients here.
It’s very important to make sure that the right size and style of wick are used, to get a good melt pool on the candle. When the wax is warm and liquid, the fragrance can evaporate easily from it, making the surrounding air full of fragrance molecules and giving a strong hot throw.
If your candle burns with a small melt pool that doesn’t reach the edge of the container, you’re not getting the most out of the fragrance and you need to increase the thickness of your wick. Be careful not to use too thick a wick though – the fragrance throw comes from evaporating the fragrance oil from the wax, not burning it – so you need a wick that gives you a steady burning flame that melts the wax but not so big that you start to see sooting. If your wick is too thick, the fragrance will be drawn up the flame and be destroyed before it can evaporate.
The wax itself can have an impact. The chemistry of wax is a huge topic of its own but in short, it can be a good analogy to think of wax as a little bit like a sponge, or a net. When you add fragrance to wax, the fragrance disperses throughout the wax like water in a sponge. It remains “trapped” in the wax, but it can come out quite easily. Different types of wax are like different types of sponge – some allow the fragrance to come out very easily and others keep it locked inside. As a candle maker, you need to find the right balance – if the sponge (the wax) is too tight, no fragrance can escape and the fragrance throw will be weak. If the sponge is too loose, the fragrance escapes too easily and you can suffer from leaching (where the fragrance leaks out of the wax and pools on the surface), problems with burning, soot, and sometimes if the fragrances leaks out, it can all evaporate too quickly and when it comes to burning it or smelling it a few weeks later, the scent is weaker.
The melting point of the wax can impact the fragrance throw – a wax that melts at a lower temperature usually has a “looser net” and so releases the fragrance a little easier. Be sure to test your candles fully to make sure that you find the right balance of melting point.
The candle making process
Once you’ve selected your ingredients, the candle making process is mostly about managing temperature – you have to find the balance when it comes to wax temperature when you are adding fragrance. You need to ensure that the wax is fully melted so that when you add and mix the fragrance, it disperses evenly throughout the wax. The closer the wax is to its congealing point, the more difficult it is for the fragrances to spread evenly. However, don’t heat it too high because if you add fragrance to very hot wax, some of the top notes can burn off during the processing and evaporate away, leaving you with a weaker fragrance once the candle is made. We recommend adding fragrance to wax when it’s heated to about 10-15 degrees above its melting point. So, if your wax melts at 52 degrees, heat the wax to about 62-67 degrees before adding. This is a good temperature to store and pour at too. You should make sure that you mix the fragrance thoroughly to get it dispersed evenly throughout the wax before pouring too – otherwise you could end up with pockets of fragrance instead of a nice even distribution, or the fragrance could all “sink” to the bottom of the jug so the first few candles you pour might contain much less fragrance than the last ones. If you’re storing fragranced wax whilst it’s heated up and melted, be sure to cover the jug or container so that the fragrance doesn’t evaporate. Turn the temperature down to keep the evaporation rate as low as possible.
When you put it all together, there are a lot of factors at play that affect the fragrance throw. The type of wax, the makeup of the various fragrance notes, the thickness of the wick, the temperature at which you add fragrance and pour the wax. These are all variables that you need to consider and unfortunately there is no one magic recipe that covers all of the variables.
Following the tips above should help you get the most out of your candle and fragrance. Our advice is to keep good notes and continue to fine tune your candle recipes’ during your candle making journey.
Feel free to leave a comment or question below with your experiences in achieving the perfect candle scent throw.