What Is Hot Throw In Candle Making?
What is Hot Throw?
Hot throw refers to the strength of fragrance released into the air when a candle is burning (Candle Making 101: Hot Throw). It describes how well the candle’s scent travels and fills the room. The quality and type of aromatic ingredients impact hot throw the most (What is Candle Throw: Improving Hot Throw & Cold Throw).
Hot throw occurs when the heat from the candle’s flame causes the fragrance oil in the wax to evaporate into the air. The hotter the candle burns, the more fragrance is released. The higher the fragrance content in the wax, the stronger the hot throw will be.
Signs of good hot throw include the scent being strongly noticeable as soon as the candle is lit, the fragrance filling the entire room, and the smell lingering even after blowing the candle out. Poor hot throw is evident when you have to be very close to the flame to smell anything, the scent is weak or doesn’t travel, and disappears immediately after extinguishing the candle.
Causes of Hot Throw
There are several factors that can affect a candle’s hot throw or the strength of its fragrance while burning:
Wick Issues
The wick is a key factor in hot throw. If the wick is too small for the diameter of the candle, it won’t burn hot enough to properly melt and pool the wax to release fragrance. Conversely, a wick that is too large can cause soot, reducing hot throw. Testing wicks and finding the proper size for each candle diameter and wax type is important.
Wax Issues
The wax composition impacts hot throw too. Some waxes like soy wax naturally have less hot throw than paraffin. Certain wax additives like vybar or palm wax can help increase fragrance throw. Properly heating and cooling wax is also key to optimizing hot throw.
Fragrance Issues
The fragrance oil itself plays a big role. Some fragrance oils naturally have less hot throw than others. Higher rates of fragrance oil typically increase hot throw, but too much fragrance can cause issues like seepage. Finding the right percentage of fragrance is important for maximum hot throw without problems.
Environmental Factors
External elements like open windows, ceiling fans, ventilation, and room size and shape can disperse fragrance and reduce hot throw. Burn testing candles in a small enclosed room is best to properly evaluate hot throw.
Testing for Hot Throw
There are a couple main ways to test for hot throw in candle making:
Nose Test
One simple way to get a sense of hot throw is to do a “nose test”. This involves smelling the unburned candle wax. You can smell the wax directly, or hold your nose close to the top of the unlit candle. This gives you an idea of the cold throw – how strong the scent is before burning. Cold throw does not always directly correlate to hot throw, but it can give you a baseline idea of scent strength (Source).
Burn Test
The best way to truly evaluate hot throw is to burn the candle and smell it. Let the candle burn for at least 1 hour, in multiple locations around the room, and evaluate the scent throw. Make notes each hour about the candle’s scent strength. Look for an even, strong scent throughout the entire burn. A weak scent, or scent that fades in and out, likely indicates a hot throw issue (Source).
Fixing Wick Problems
Two common wick issues that can cause problems with hot throw are wick size and wick centering. Using the wrong wick size for the wax and container can lead to the wick being drowned or mushrooming, preventing optimal hot throw. The standard recommendation is to use a larger wick for containers with a wider diameter. Test different wick sizes like CD, ECO, and LX to find the best option for complete melt pool and fragrance diffusion (https://www.candlescience.com/learning/how-to-choose-wick-size/).
Proper wick centering is also essential for even burning and hot throw. If the wick is off-center, the melt pool will be uneven, preventing the fragrance from being released evenly. Carefully center the wick when pouring candles to ensure symmetry. Use wick stickers or adhere the wick with a small amount of wax on the bottom of the container before pouring the rest of the wax. Check for centered wicks by observing the melt pool as the candle burns.
Fixing Wax Issues
One of the main factors affecting hot throw is the wax itself. The melting point of the wax plays an important role. Waxes with lower melting points tend to give off more fragrance as they melt compared to harder waxes. According to this source, soy wax has a lower melting point than paraffin, making it release fragrance more readily. When working with soy wax, try blending in a small amount of paraffin to raise the melting point slightly which can improve hot throw.
Additives mixed into the wax can also impact hot throw. Some candle makers recommend adding a small amount of beeswax or vybar to soy wax, usually 5-10%, to help “anchor” fragrances and improve scent throw. The additives modify the wax crystallization which helps retain and disperse fragrance better. As noted in this post, vybar improves both cold throw (unlit) and hot throw in soy candles.
Fixing Fragrance Issues
There are a few key things to check when it comes to your fragrance if you are having issues with hot throw:
Fragrance Load – Using too little fragrance oil can result in a weak hot throw. Most experts recommend using 5-10% fragrance load for soy candles. Going above 10% does not necessarily increase hot throw and can actually cause other issues like soot (source: https://www.candlescience.com/learning/candle-making-101-hot-throw/).
Fragrance Notes – Fragrances containing a high percentage of top notes rather than middle and base notes will not have as strong of a hot throw. This is because the top notes tend to burn off more quickly. Choosing a fragrance oil with more middle and base notes can help improve hot throw (source: https://nightskycandle.com/blogs/news/cold-throw-hot-throw-soy-candles).
Fragrance Binding – Properly binding the fragrance oil to the wax is critical for good hot throw. Not stirring thoroughly after adding fragrance can lead to poor binding and weak hot throw. Letting the wax fully cool before adding fragrance can also inhibit binding. Adding at the right temp allows the fragrance to properly bind to the wax molecules (source: https://nightskycandle.com/blogs/news/cold-throw-hot-throw-soy-candles).
Environmental Factors
Environmental factors like room size, ventilation, and burner location can significantly impact hot throw. According to this source, hot throw tends to be stronger in smaller, enclosed spaces compared to large, open areas. In large rooms with high ceilings, the fragrance can dissipate and weaken before reaching someone’s nose. Drafty areas near windows or doors can also reduce hot throw.
The location where the candle is burned makes a difference as well. Placing the candle in a corner or on an enclosed shelf blocks air circulation, trapping the fragrance. Burning the candle in an open area in the center of the room allows the scent to readily disperse. For strongest hot throw, place the candle in a small, enclosed space away from windows and doors.
Preventing Hot Throw
One of the best ways to prevent hot throw issues is to thoroughly test your candles before selling or gifting them. Testing allows you to identify and fix any problems with wicks, wax, fragrance load, and other factors that could lead to poor hot throw. Here are some tips for testing candles:
- Test burn your candles in a variety of environments – a small enclosed room, a large open space, etc. This will show you how the candle performs in different settings.
- Let the candle burn for at least 2-3 hours and evaluate hot throw performance over time. Often hot throw will decrease as the candle burns down.
- Burn multiple candles with the same specs to ensure consistency. Test different wicks, wax types, fragrance loads, vessel shapes, etc.
- Take notes on each candle’s performance. Rate hot throw strength on a scale of 1-10 at various points during testing.
- Ask others to test candles and give feedback. Different noses perceive scent differently.
Following best practices for wicks, wax, fragrance load, and other factors is also key for avoiding hot throw issues. But thorough testing is the best way to prevent problems and achieve excellent hot throw.
When to Be Concerned
Mild cases of hot throw are common and usually not a major cause for concern. This includes candles that have a light or faint scent when burning or scents that don’t seem to fill the whole room. Try simple troubleshooting steps first like trimming the wick or letting the wax cure longer.
More severe cases of hot throw are problematic and need to be addressed. Signs of severe hot throw include candles that emit a strong, overpowering scent within seconds of lighting, scents that give you a headache or make you nauseous, black smoke, or flames that exceed 1-2 inches in height. Severe hot throw indicates an issue with wick size, wax quality, fragrance load, or environmental factors. Proper wick sizing and testing fragrance loads between 5-10% are key preventative steps. If severe hot throw persists, it’s best to remake the candle with adjustments.
Conclusion
In summary, hot throw refers to the strength of a candle’s fragrance when it is burning. It is an important factor for candle makers to consider, as a weak hot throw can negatively impact the candle-burning experience. The main causes of poor hot throw are wick issues, wax problems, and ineffective fragrance oils. However, environmental factors like room size and airflow can also affect hot throw. There are several steps candle makers can take to test for and improve hot throw, such as double-wicking, using proper wax blends, and adding fragrance oil. While a candle with poor hot throw is frustrating, it does not necessarily mean the candle is unsafe to burn. As long as basic safety precautions are followed, the candle should still burn effectively. The key is for candle makers to understand what factors impact hot throw and how to tweak their process when needed. Addressing hot throw issues results in a superior candle product that delivers a satisfying scent experience.
