Having a candle without a scent is like having a cake without icing. Sure, it’s okay, but it’s not nearly as sweet! For most, the whole point of burning a candle is to fill the air with its lovely aroma. A common conundrum for new candle makers is wondering just how much fragrance oil is needed to give off that perfect, sought-after scent throw.

Here we are going to look at how to calculate the proper amount of fragrance oil to add to your wax as well as what other factors can influence the performance of your candle’s scent throw.

How to Calculate Maximum Fragrance Load?

Despite what you may think, more doesn’t necessarily mean better when it comes to adding fragrance oil to wax. It’s important to find the perfect ratio of fragrance oil to wax so your composition isn’t ruined, and the scent doesn’t fall flat. There is a science behind candle making to do it right.

When you select the wax that you will be working with, you will notice that the wax manufacturer provides a maximum fragrance oil load percentage. This number is generally based on weight, and it is meant to tell you the maximum amount of fragrance oil that the wax can hold successfully. 

Keep in mind that just because the wax is able to hold that percentage of fragrance oil, doesn’t necessarily mean that the full amount is needed. However, you don’t want to exceed this amount, or it can negatively impact your candle structure. If you are unable to find the maximum fragrance load percentage for your wax, it is usually safest to stay within the range of 5-6%.

Let’s go over the formula for figuring out the amount of fragrance oil to add to your wax. To simplify it, we’ll say that we are going to use 1 pound of wax (which is equal to 16 net weight ounces - not fluid ounces) and the maximum fragrance load is 10%. Begin by dividing the maximum fragrance load percentage by 100 to make it a decimal number (10 ÷ 100 = .10). Then multiply the decimal number by the number of wax ounces you are using (.10 x 16 = 1.6). The result will tell you the maximum ounces of fragrance oil you can add to the 16 ounces/1 pound of wax. In this case, you should not exceed 1.6oz of fragrance oil.

Be sure to document your findings for each type of wax you use to save you the trouble of having to figure out the maximum fragrance load every time you use that wax.

How Much Fragrance Oil Should You Use?

Now that you have determined the maximum fragrance load, you will need to do some testing to establish the most effective quantity of fragrance oil to add to your candle recipe to achieve the scent throw you desire. Just because the wax is capable of holding a certain amount of fragrance oil, doesn’t mean that you need to use that much. Unfortunately, there is no fool proof amount that works for every different fragrance oil/wax/wick combination, so testing is a definite must.

Fragrance oils are made up of a multitude of unique ingredients that include carrier oils, essential oils, and other synthetic components. Each ingredient can have a differing effect on the hot throw of your candle. Sometimes going all out with your fragrance load can cause your candle to give off the unpleasant smell of burning fuel rather than the exquisite aroma you were going for. Not only that, but if you can get a beautiful scent from adding only 6% fragrance load, then why take on the extra cost of adding the maximum 10-12%?

What Happens If You Add Too Much Fragrance Oil?

There are a few different things that can happen if you overload your wax with fragrance oil:

1. It could cause the wax to not set up properly, leaving it soft and oily.

2. The fragrance oil could leak out of the wax after it has set, leaving a puddle of oil on the top, at the bottom or all along the sides of your candle.

3. It can cause the candle to give off an unpleasant burning fuel smell.

On the other end of the spectrum, if you under scent your candle, the only negative is that your candle will have a very faint scent throw.

Why Measure by Weight Instead of Volume?

Candle making experts will tell you that wax, and fragrance load must be measured in terms of weight and not volume, and if you want to be accurate this is true. Every fragrance oil and wax type have different levels of density. This means you could melt down 1 pound of one type of wax and end up with 16 fl oz of liquid, and then melt down another denser wax and end up with 18 fl oz of liquid. This also means that if you were to measure out 1 fl oz of one type of fragrance oil, it will weigh less than 1 fl oz of a denser fragrance oil. If you want to have your candle recipe be precise, it is highly recommended that you purchase a scale for measuring out your ingredients.

What if You Max Out The Fragrance Load and Still Have No Scent?

It can be so frustrating to have gone through all your testing, added the maximum fragrance load and still find that your candle has little to no scent. How could that be?! Here are some possible answers to that question:

1. The fragrance didn’t bind properly with the wax. This could be due to adding it at too low of a temperature. The wax manufacturer will provide a temperature recommendation for adding fragrance oil, and this is an excellent place to start; However, if you find that your candles consistently don’t give off a great scent throw, you may want to increase the temperature you add your fragrance oil slightly to see if that helps improve your scent throw.

2. Your wick is too small. If the wick you are using in your candle isn’t hot enough, it won’t throw the scent well. If your flame is small and it takes longer than 3-4 hours for your melt pool to reach the edge of your candle, try increasing your wick size slightly to see if your scent throw gets better.

3. You didn’t allow your candle to fully cure. Candles require a certain amount of time to thoroughly set which will allow for the best possible scent throw. Generally, it is recommended that you leave your candles to cure for 2 full weeks before doing a test burn.

4. The fragrance oil may be more suitable for a different type of wax. If you find that a fragrance isn’t working well in 1 type of wax, you may want to try it in a different kind to see if it works better

5. The fragrance oil is a subtle scent. If you find that a fragrance oil has a very soft and understated scent when smelling it straight from the bottle, there is a good chance that it will be the same or possibly even more subtle when you add it to your candles. Some people favour a softer scent, but if you prefer a stronger smell, you will want to use fragrance oils that are very potent especially in their most concentrated form.

Conclusion

It is so important to add the proper amount of fragrance oil to your wax if you want to make a candle that will both burn correctly and smell amazing. The only way to do that accurately is through the use of math and testing. While it may not be the most exciting aspect of candle making, it’s crucial for creating a good quality candle.

It is highly recommended that you buy a sample size of any new fragrance oils you are considering adding to your collection before investing in larger quantities. This will give you the opportunity to fully test it in a small batch of candles to ensure that the oil works well in your chosen wax and meets your personal standards.