How to Properly Conduct a Candle Burn Test: A Step-by-Step Guide

A beautiful candle surface, a pleasant fragrance, and a centered wick do not automatically mean that the candle performs well. The real test begins when the candle is lit.

A wick that is too small can lead to tunneling, weak flame performance, and poor hot throw. A wick that is too large can cause an overly aggressive flame, soot, excessive heat, and a wax pool that becomes too deep too quickly.

Choosing a wick based only on the container diameter is not enough. Wick performance depends on the entire candle formula: the wax, fragrance oil, fragrance load, dye, and the size and shape of the container.

That is why every new candle formula should go through a burn test.

But a proper burn test is not just one long burn. It should be treated as a series of controlled burn cycles, allowing you to observe how the candle behaves from the first burn almost to the end of its life.

At M | Art Studio, for scented container candles, we recommend limiting one burn cycle to about 2-3 hours. With longer continuous burning, the melted wax and the container continue to heat up, the fragrance evaporates more intensely, and the scent character may begin to change and become less pleasant.

Because of this, it makes sense to test scented candles under the same conditions in which they are meant to be used.

Let’s go through the process step by step.

What Is a Candle Burn Test?

A burn test is the process of evaluating a finished candle under real use conditions.

During testing, you should observe:

• flame stability;
• how the melted wax pool forms;
• the width and depth of the melted wax pool;
• smoke and soot;
• carbon buildup or “mushrooming” on the wick;
• wick behavior;
• container heat;
• hot throw;
• how evenly the wax is consumed;
• how the candle behaves after several burn cycles;
• how it performs in the final third of the container.

The main goal of testing is to find the right balance of container + wax + wick + fragrance oil + dye so that the candle burns in a stable and predictable way throughout its life.

This is why a wick size chart should only be treated as a starting point. The final wick choice can only be confirmed through testing.

When Should You Run a New Burn Test?

One of the most common mistakes beginners make is choosing a wick once for a certain jar diameter and then using that same wick size for every candle.

In reality, that is not enough.

You should run a new burn test whenever you make a significant change to the formula, including:

• changing the wax type or wax brand;
• changing the wick series;
• changing the wick size;
• changing the container size or shape;
• changing the fragrance oil;
• changing the fragrance load;
• changing the amount of dye;
• changing the number of wicks;
• changing any other important part of the formula.

Even two different fragrance oils added at the same percentage can affect wick performance differently.

For consistent results, it is best to treat each new combination of materials as a separate candle formula that needs to be tested.

When Can You Start Testing a Candle?

You should not test a candle immediately after pouring it.

The wax needs time to fully set and stabilize. In scented candles, the fragrance oil also needs time to distribute properly throughout the wax.

For an initial technical wick test, it is usually enough to let the candle rest for a few days after pouring.

If you want to evaluate not only the burn performance but also the hot throw more accurately, it is better to allow the candle more time to cure.

So in practice, you can separate testing into two stages:

• an early technical test to evaluate the wick, wax, and container behavior;
• a full burn test after curing to also evaluate hot throw more accurately.

It is important to test under consistent conditions. If one candle is tested two days after pouring and another one two weeks later, the results will be harder to compare.

What You Need for a Burn Test

You do not need complicated equipment to test candles at home.

Prepare:

• finished test candles;
• a ruler;
• wick trimmers or scissors;
• a timer;
• a notebook or test sheet for recording results;
• a phone for taking photos;
• if available, a thermometer to monitor the container temperature.

If you are trying to choose the right wick size, it is best to make several identical candles.

For example:

• the same wax;
• the same container;
• the same fragrance oil;
• the same fragrance load;
• the same dye;
• but different neighboring wick sizes.

This makes it much easier to compare the results and choose the best wick.

Record the Formula Before Testing

Before the first burn, always record the candle formula.

For example:

• Wax: KeraSoy Container
• Container: 200 ml
• Inner diameter: 70 mm
• Wick: Wedo Stabilo 14
• Fragrance: Fresh Cut Peony
• Fragrance load: 10%
• Dye: 2 drops
• Pour date: ...
• Test start date: ...

If you are testing several very similar candles, label each one clearly.

After a few burn cycles, it becomes surprisingly easy to forget which candle had which wick.

It is also very helpful to take photos at the same points in each test. Over time, this gives you your own library of tested formulas.

Prepare the Right Testing Environment

Place the candle on a stable, level, heat-resistant surface away from:

• curtains;
• paper;
• flammable objects;
• open windows;
• fans;
• air conditioners;
• strong drafts.

Air movement affects the flame and heat distribution, so it can distort the test results.

If you are testing more than one candle at the same time, do not place them too close to each other. They should not heat each other.

And most importantly: never leave a burning test candle unattended.

Step 1. Trim the Wick

Before lighting the candle, trim the wick.

For many cotton wicks, a starting length of about 5–6 mm works well, unless the wick manufacturer recommends otherwise.

This is especially important when comparing several candles. All test candles should start under the same conditions.

If one wick is left long and another is trimmed properly, the differences in flame size, soot, and wax melt may come from wick length rather than wick size.

Use the same preparation before every new burn cycle.

Step 2. Light the Candle and Start the Timer

Record the exact time you light the candle.

For a scented container candle, we recommend a test cycle of up to 2 hours.

Do not light the candle and only check it at the end. The most useful information comes from observing it as it burns.

A practical schedule is:

30 minutes → 1 hour → 1.5 hours → 2 hours.

What to Check After 30 Minutes

At the beginning of the test, focus mainly on the flame.

Check:

• did the candle light easily;
• is the flame stable;
• does the flame look too small;
• does it look too tall;
• is there strong flickering;
• is there smoke;
• is there visible soot;
• is there early mushrooming on the wick.

At this stage, the melted wax area may still be small.

That is completely normal.

Do not assume the wick is too small just because the wax has not melted all the way to the edges after 30 minutes.

What to Check After 1 Hour

After about one hour, you can evaluate both the flame and the development of the melted wax pool.

Look at:

• whether the melted wax area is expanding;
• whether the wax is melting evenly;
• whether the flame remains stable;
• whether the flame is becoming too large;
• whether there is smoke or soot;
• whether mushrooming is developing;
• whether the fragrance begins to open up.

At this point, hot throw may already be noticeable, but it is still too early for final conclusions.

If several candles with the same fragrance are burning at the same time, it is almost impossible to evaluate each one’s scent properly. When choosing a wick, focus first on burn quality. A dedicated hot throw test can be done separately afterward.

What to Check After 1.5 Hours

By this point, the melted wax pool becomes one of the key indicators.

Evaluate:

• the width of the melted wax pool;
• the depth of the melted wax pool;
• how much wax remains near the walls of the container;
• flame size and stability;
• wick condition;
• soot;
• container heat;
• fragrance strength and quality.

It is important not to judge any one factor in isolation.

For example, a full wax pool may look impressive, but if the flame is too large, the wax is being consumed too quickly, and the container is getting too hot, the wick may actually be too strong.

What to Check After 2 Hours

Two hours is the key point of our test cycle.

Before extinguishing the candle, evaluate the overall picture.

Flame

The flame should remain reasonably stable.

Pay attention to:

• excessive height;
• constant strong flickering;
• smoke;
• soot;
• a clear increase in flame size compared with the beginning of the test.

Melted Wax Pool

Look at how far the melted wax has spread toward the walls of the container.

But do not try to force a perfect full wax pool within the first 2 hours of the first burn.

A small ring of unmelted wax near the edges during the first few cycles does not automatically mean the wick is too small.

As the candle burns down, the heat behavior inside the container changes, and some of that remaining wax may melt during later burn cycles.

Depth of the Melted Wax

The melted wax should not become excessively deep.

If a large amount of wax becomes liquid very early, the flame grows too large, and the candle burns quickly, the wick may be too strong for the formula.

Wick

A small amount of carbon buildup can happen even in a good-performing candle.

But a large, continuously growing mushroom, especially when combined with a large flame and soot, deserves attention.

Container

Always pay attention to container heat during the test.

If you have an infrared thermometer, it is helpful to measure the temperature at the same points during each cycle and record the results.

What matters is not only the number itself, but the pattern: how quickly the container heats up and whether that heat becomes significantly more intense as the candle burns down.

The candle container should be suitable for the heat conditions created by a burning candle.

If you notice damage or other signs of unsafe behavior, stop the test.

Fragrance

By the end of the 2-hour cycle, you can evaluate:

• how well the fragrance spreads through the room;
• whether the scent keeps its intended character;
• whether the fragrance becomes too heavy;
• whether unpleasant or distorted notes appear.

At M | Art Studio, we do not recommend continuing to burn a scented candle for more than 2 hours without a break.

As heating continues, the melted wax and the container become hotter, fragrance components evaporate more intensely, and the scent character may start to change.

After 2 hours, extinguish the candle and allow it to cool completely.

A Full Wax Pool After 2 Hours Is Not Always the Goal

This is one of the most important principles of proper testing.

Sometimes a candle maker sees a small amount of wax remaining near the walls after 2 hours and immediately decides to move up to a larger wick.

The next wick may indeed melt the whole surface quickly.

But at the same time, it may also create:

• a flame that is too large;
• a wax pool that is too deep;
• faster wax consumption;
• stronger container heat;
• larger carbon buildup on the wick;
• soot;
• more aggressive fragrance evaporation.

So in the process of chasing a visually perfect surface, we may actually make the candle perform worse overall.

The correct wick is not the one that melts the entire surface as fast as possible.

The correct wick is the one that creates balanced performance throughout the candle’s life.

Step 3. Extinguish the Candle and Let It Cool Completely

After 2 hours, extinguish the candle.

Do not move the container immediately, because the wax inside is still hot and liquid.

Let the candle cool completely and allow the wax to solidify again.

Only start the next burn cycle after the candle has fully cooled.

Before relighting:

• remove heavy carbon buildup if needed;
• trim the wick again to the recommended length;
• record the new cycle number;
• start the timer again;
• repeat the observations.

This is how you gradually test the candle from the top all the way down through the container.

Why One Burn Cycle Is Not Enough

This is a crucial point.

Even if the candle performs beautifully in the first 2 hours, the test is not finished.

As the candle burns down, its heat behavior changes.

At the beginning, a larger mass of solid wax surrounds the flame and absorbs part of the heat.

Later, the wax level goes down, the flame sits deeper inside the container, and the walls and bottom receive more heat.

Because of this, a candle may behave very differently at the start and near the end of its life.

For example, a wick that seems slightly too small in the first two cycles may begin to perform perfectly later.

And a candle that produces a very large wax pool from the first burn may become too aggressive near the bottom of the container.

That is why a proper burn test is a series of 2-hour cycles repeated through almost the entire life of the candle.

What to Watch During Later Burn Cycles

During each new test cycle, continue recording the same parameters:

• flame size;
• flame stability;
• width of the melted wax pool;
• depth of the melted wax pool;
• remaining wax on the container walls;
• carbon buildup on the wick;
• soot;
• container temperature;
• hot throw;
• overall burn time.

It is especially useful to observe the candle at the same time points during every cycle, for example after 30, 60, 90, and 120 minutes.

This makes the results much easier to compare.

Pay Special Attention to the Final Third of the Candle

The final third of the container is especially important when evaluating wick performance.

At this stage, the flame is much lower in the container, and the heat conditions are different from the beginning.

This is where you should pay especially close attention to:

• flame height and behavior;
• how quickly the melted wax pool forms;
• the depth of the melted wax;
• the temperature of the walls and bottom;
• soot;
• wick condition;
• wick tab stability;
• fragrance character.

If problems only appear in the lower part of the candle, the formula still needs improvement.

The candle should perform well not just at the beginning, but throughout its life.

That said, there is no need to burn the candle down to a completely dry container. A finished candle should always include instructions for when the user should stop burning it.

How to Recognize a Wick That Is Too Small

Possible signs include:

• a small, weak flame;
• very slow formation of the melted wax pool;
• a narrow melt area around the wick;
• clear tunneling after several burn cycles;
• a large amount of wax consistently left on the walls;
• a flame that becomes weaker over time;
• the wick beginning to drown;
• the candle extinguishing itself;
• weak hot throw.

But remember:

An incomplete wax pool after the first 2-hour burn cycle does not automatically prove that the wick is too small.

First, see what happens in the second, third, and later cycles.

How to Recognize a Wick That Is Too Large

A wick that is too strong may show these signs:

• an excessively tall flame;
• constant strong flickering;
• smoke;
• soot on the container;
• a large mushroom on the wick;
• a full wax pool forming very quickly;
• an excessively deep liquid wax layer;
• rapid wax consumption;
• strong container heat;
• worse performance as the candle burns lower.

If several of these signs appear together, it may be time to test the next smaller wick size.

What Does a Properly Sized Wick Look Like?

In a well-balanced container candle:

• the flame remains stable;
• there is no constant smoke or visible soot;
• the melted wax pool forms gradually;
• the candle does not develop a severe lasting tunnel;
• after several cycles, large amounts of wax do not remain on the walls;
• the melted wax does not become excessively deep;
• the wick does not continuously produce a large mushroom;
• the container behaves steadily;
• the wax is consumed reasonably evenly;
• the fragrance opens up well during burning.

The key word here is balance.

You cannot judge a wick by only one factor, such as the width of the wax pool.

How to Compare Several Wick Sizes Properly

Let’s say you have a container of a certain diameter and you chose an initial wick size based on the manufacturer’s guide.

Instead of making just one candle, make three:

• Candle A — one wick size smaller than your estimated choice;
• Candle B — your main test wick size;
• Candle C — the next larger wick size.

All other variables should remain exactly the same.

Run 2-hour burn cycles under the same conditions and record the results for each candle.

Even after the first cycle, you will already see differences.

For example:

• one candle may have a flame that is too small;
• another may look stable;
• the third may already look more active and aggressive.

But do not choose the winner too soon.

Continue testing all three. In many cases, the best wick only becomes obvious after several cycles, especially in the second half of the candle.

How to Evaluate Hot Throw Properly

Hot throw is closely connected to burn performance.

For a fragrance to spread well through the room, the candle needs a sufficient melted wax surface.

If the wick is too small and the melted wax area stays very narrow, the hot throw may be weaker.

But that does not mean that the solution is always a larger wick.

A wick that is too large can overheat the wax. As a result, the fragrance may evaporate faster and the scent may begin to smell different from what you intended.

So first, you need to achieve stable, balanced burning. Only then can you properly evaluate fragrance performance.

For a more objective hot throw test:

• use a fully cured candle;
• test one scented candle at a time;
• use the same room for each test;
• avoid strong drafts;
• do not use other candles, diffusers, or strong perfumes at the same time;
• allow the candle to develop a sufficient melted wax surface;
• evaluate the fragrance during a normal 2-hour burn cycle.

Keep in mind that hot throw depends not only on fragrance load. It is also affected by:

• the wax type;
• the fragrance oil itself;
• fragrance concentration;
• wick size;
• the size of the melted wax surface;
• room size;
• air movement.

So the idea that “more fragrance oil automatically means a stronger scent” does not always work.

Keep a Burn Test Log

If you make candles regularly, detailed notes will save you both time and materials.

Your log can include:

Formula

• wax;
• container;
• inner diameter;
• wick;
• fragrance oil;
• fragrance load;
• dye;
• pour date;
• test start date.

Then, for each cycle, note:

• 30 minutes — flame / wax pool / soot / temperature;
• 1 hour — flame / wax pool / fragrance / temperature;
• 1.5 hours — flame / wax depth / wick / fragrance;
• 2 hours — overall condition / wax pool / temperature / hot throw.

After full cooling, record:

• the candle surface condition;
• wax left on the walls;
• wick condition;
• the next cycle number.

If you want, you can also weigh the candle before and after each cycle. This helps compare how quickly different wick sizes consume wax.

Over time, this log becomes your own personal library of tested formulas, and it will be much more useful than any general wick chart.

Why You Should Not Simply Copy Someone Else’s Formula

You may find a recommendation that says something like:

“For a 7 cm diameter jar, use this wick size.”

But even if another candle maker uses the same container diameter, the result may still be different.

Possible reasons include:

• a different wax;
• a different fragrance oil;
• a different fragrance load;
• a different dye;
• differences in container shape;
• a different wick series.

That is why manufacturer recommendations and another maker’s experience are useful only for deciding where to start testing. They cannot replace testing itself.

At M | Art Studio, we offer Wedo Stabilo cotton wicks in several sizes, making it easier to choose neighboring wick sizes and perform proper comparative testing.

Common Burn Testing Mistakes

Mistake 1. Drawing Conclusions After 30–60 Minutes

At that stage, you can evaluate the flame, but not the candle’s long-term behavior.

Mistake 2. Expecting a Full Wax Pool During the First Test

A small amount of wax near the walls during the first cycles is not always a problem.

Mistake 3. Using a Larger Wick Just to Get a Beautiful Wax Pool

A larger wick may melt the surface faster, but it may also create a pool that is too deep, cause soot, and overheat the container.

Mistake 4. Burning a Scented Candle Too Long in One Cycle

Long continuous burning causes the melted wax and the container to keep heating up.

We recommend limiting one burn cycle of a scented candle to about 2 hours, then allowing it to cool completely.

Mistake 5. Testing the Candle Only Once

The first burn only shows the beginning of the candle’s behavior.

A proper test should include several cycles almost to the end of the candle.

Mistake 6. Ignoring the Final Third of the Candle

This is where overly strong wicks and excessive heat often reveal themselves.

Mistake 7. Changing Several Variables at Once

If you change the wax, fragrance load, and wick size all at the same time, you will not know what caused the difference in performance.

For a proper comparison, change one variable at a time.

Mistake 8. Using One Successful Test for Every Fragrance

One wick may work beautifully with one fragrance and behave differently with another.

Mistake 9. Judging Only by the Wax Pool

A nice-looking melted wax surface does not automatically mean the candle is performing correctly.

You also need to evaluate the flame, wick, soot, wax depth, wax consumption, container heat, and fragrance behavior.

Should You Burn Test Candles Before Selling Them?

Absolutely.

If the candle is meant for sale, burn testing is not an extra step. It is part of product development.

Every new formula should be tested before you make a larger batch.

It is far better to use a few candles for testing than to produce dozens of candles and only later discover that the wick choice was wrong.

And even after a formula has already been tested successfully, any major material change, such as a different wax, wick, or fragrance load, is a reason to test again.

The Main Rule of Candle Burn Testing

There is no universal formula like:

“a 7 cm jar = one exact wick size.”

It is much more accurate to think of a candle as a full system:

container + wax + wick + fragrance + fragrance load + dye = one formula.

Changing one component can change the performance of the whole candle.

That is why manufacturer recommendations are only a starting point. The final decision should always be based on testing.

For scented candles, we recommend testing through a series of controlled burn cycles of up to 2 hours each, allowing the wax to cool completely between cycles.

Do not judge the candle only by the first burn. Test it in the middle and especially in the final third of the container.

And do not chase a perfectly full wax pool as quickly as possible.

A good candle is not the one that melts all the wax around the wick as fast as possible.

A good candle is a balanced formula that burns steadily, consumes wax properly, reveals the fragrance well, and behaves predictably from the first burn cycle to the last.

At M | Art Studio, you can find materials for making and testing container candles: natural KERAX waxes, Wedo Stabilo cotton wicks in different sizes, wooden wicks, professional fragrance oils, dyes, containers, and the tools you need for candle making.