Why Temperature Is the Deciding Factor

Many beginner candle makers think you can just pour fragrance oils in at any point during the melting process. Unfortunately, candle wax doesn’t work that way. Wax has a crystalline structure that expands when heated and contracts when it cools. You need to add the fragrance oils at the moment when the wax molecules are open enough to absorb the oil, but not so hot that the fragrance molecules evaporate immediately.

Every fragrance oil has a flash point. This is the temperature at which the oil becomes flammable when exposed to a spark. When adding it to melted wax, you don’t need to worry about a fire hazard, but a higher temperature does cause the scent to evaporate more quickly. For citrus oils, this point is often lower, around 60 to 65 degrees Celsius. A reliable thermometer is therefore essential.

The ideal addition temperature for each type of oil

The temperature at which you add the fragrance depends largely on the type of oil you’re using.

• Synthetic fragrance oil: For most fragrance oils, a temperature between 70 and 80 degrees Celsius is ideal. At this temperature, the wax molecules are open enough to form a stable bond. Some manufacturers even prefer 85 degrees for optimal bonding with specific types of wax.
• Essential oils: These natural extracts are much more volatile. The optimal temperature for adding essential oil to candles is between 60 and 65 degrees Celsius. If you add them at a higher temperature, you’ll lose much of their therapeutic effect and fragrance intensity.

The 2-Minute Rule for a Stable Mix

This is perhaps the step that’s most often skipped. After you’ve poured the fragrance into the laundry, you need to stir it. Don’t just give it a quick stir three times—stir gently and thoroughly for at least two minutes.

You’re trying to blend two different substances together. By stirring for two minutes, you ensure that the fragrance molecules are evenly distributed. If you don’t do this, you’ll end up with spots in the candle that are very fragrant and spots with no fragrance at all. In extreme cases, the oil may even sink to the bottom or separate and form a film on the surface. Read more here about how to prevent problems when mixing candle ingredients.

Exactly how much fragrance oil should you use?

More oil doesn’t automatically mean a stronger candle. Every type of wax has a saturation point. If you add too much oil, the wax simply can’t hold it. The excess oil will then form droplets on top of the candle, which can be dangerous if the flame reaches that pool of oil.

Most types of wax, such as soy wax, can handle a fragrance concentration of 6% to 10%. Because oil is lighter than water, 100 milliliters of oil is not the same as 100 grams. Therefore, always use weight as your measure. Suppose you have 1 kilogram of wax; in that case, use between 60 and 100 grams of candle fragrance oils. Always start with a small test batch to find the best dosage.

The Importance of Patience and Perseverance

Your candle has been poured and looks beautiful. You’ll probably want to light it right away. Don’t do it. Immediately after it sets, the fragrance oils are still loosely trapped between the wax crystals. The candle needs time to cure. During this process, the wax crystallizes further, and the scent is, as it were, locked into the structure.

• Paraffin: Can often be burned after just 48 hours.
• Soy wax and rapeseed wax: They really need 1 to 2 weeks to release their scent most effectively.

If you light a soy candle too soon, the scent projection is often disappointingly weak. Give the wax the time it needs to fully bind the scent molecules. You can learn more about this in our article on long-lasting candle scents.

The Role of the Wick in Scent Diffusion

Even with the perfect temperature and blend, the wrong wick can ruin your results. The wick is the heart of your candle. If the wick is too small, the pool of melted wax won’t be large enough and won’t reach the edges of the glass. As a result, not enough fragrance will be released. If the wick is too large, the candle will get too hot and the fragrance oils will burn off before they can diffuse.

For natural waxes with stronger scents, such as amber or sandalwood, wooden wicks often work very well. Be sure to check out our tips for making candles with essential oils for more information on the right materials.

Making a fragrant candle is a process of trial and error. Always write down the temperature at which you added the fragrance and how much you used. That way, you can replicate a successful batch time and time again and always enjoy a home filled with wonderful aromas. Check out our full selection of candle-making supplies to get started right away with the best ingredients.