Common Burn Issues

The proper wick for any given candle provides a correctly sized burn pool, does not extinguish before end of life, and has a safe, pleasant flame height.

When observing the characteristics of an optimized burn, it is important to achieve a properly sized burn pool, minimal sooting and a well-sized flame throughout the length of the entire candle’s life. Container candles may entrap an increasing amount of heat as they burn, so the way a candle burns in the first half of its life may not indicate how it will burn toward the end.

That’s why a candle needs to be thoroughly tested to its completion.  There are no shortcuts in the pursuit of a quality candle.

Problem #1:  The Burn Pool

The burn pool serves two main functions for a candle. It provides the liquid fuel required by the flame and it regulates the “hot scent throw”.


In general, choosing too large a wick will result in excessive flame size and hence a deep burn pool, causing too large a portion of the candle to liquefy, and, in the case of pillar candles, collapse the walls.

Too much heat will also cause the fragrance to break down, reducing the evaporation of scent and requiring a greater flow of oxygen which, in turn, contributes to burning inconsistency and “sooting.”

Too small a wick will either cause the wick to drown in its burn pool or to create too small a pool resulting in “tunneling” and reduction of burn time.

In both cases, the customer will almost certainly feel disappointed by his or her purchase. The choice of the proper wick for a particular candle’s composition will determine the success of the burn pool and ultimately, the customer’s satisfaction.


Problem #2:  Flame Height

Flame height is another determining factor in judging the overall burn of the candle and it is also ultimately determined by the wick choice.

After all, the wick is the candle’s sole conduit for fuel. Too high a flame not only will cause “sooting” but can also become quite dangerous.

Soot is the black substance found in smoke. It is comprised of tiny particles of unburned fuel and its excessive presence indicates incomplete combustion and the improper wick choice.


Problem #3:  Mushroom Capping

Mushrooming occurs when there is an overabundance of wax fuel to be combusted, creating a build up of partially reduced molecules which are unable to reach the flame, combining with oxygen and completing the burning process.

As a result, the incompletely combusted material falls back onto the wick and builds up as a carbon cap on the end of the wick.

This excess fuel can be caused by an oversized wick providing more wax to the flame than can be burned; or the wrong type of wick in general.


Problem #4:  Afterglow

Afterglow occurs when an individual manually extinguishes the flame but the charcoaled mass at the end of the wick continues to throw off soot. All wicks do this to some extent when they are blown out, but it becomes “afterglow” when it continues past a reasonable amount of time.

This condition most often occurs as a direct result of mushroom capping during the burn.

The Solution

Wicks Unlimited’s free wick optimization candle test burning support service.

Smoking, sooting, wick drowning, short burn times, glass breaking, unsafe flame size and tunneling can all be remedied by the choice of the right wick.  As such, we purposely did not offer “this wick size for this candle size” recommendations on this website.  We will be pleased to individually analyze each of your applications and make our recommendations as to the proper wick-clip assemblies for your product, taking into consideration your wax formulation, scent, dye and candle size.  We perform this service at no charge for our Customers.

We appreciate the opportunity to assist you with your test burning as we want our Customers to feel good about their finished product and about their relationship with Wicks Unlimited.  Test burning a wide assortment of candles allows Wicks Unlimited to gain a great deal of product knowledge which then helps everybody.  The individual results of all our test burns are considered proprietary between Wicks Unlimited and our Customer.

One would hope that 300 wicks were enough to cover every possibility…but they are not.

With the imagination and creativity of the candle industry, new challenges are constantly being presented.  The communication channels between Wicks Unlimited and our wick manufacturers are wide open, with new wicks being created based on the feedback from Wicks Unlimited’s testing lab.



With a little help from your friends in the candle industry…


You can have this.  


Schedule Your Candle Optimization Today!

Recent Blogs