Test Burning Jar Candles

This is a subject that is often hotly debated by candle makers. What is the criteria for properly testing your jar candles burn? This blog will help you to determine how to most effectively burn test your candles for the proper wick size, proper burn and also for the best possible scent throw BUT it also addresses specific testing criteria set forth by the ASTM for SAFETY!!!

For my test, I will be making a paraffin blend container candle. When using paraffin wax, you must cure your candles at a minimum 24 hours before burning to ensure the wax is properly cured, for soy, soy blends and palm, a 48 hour minimum is required. Keep in mind that contrary to popular belief that scent in paraffin candles and ALL candles may also take up to two full weeks to cure. But to test the burn, not the scent throw, you can test starting at 24-48 hours post production. This candle is made using the IGI 4630 Paraffin Blend (Formerly Astor J-50) wax. 

My first test is always to test a four complete hour burn and look at what I have. Be certain always to time this. (To test, don't test more or less, just the four hours exactly at first.) I examine the melt pool depth and width, the flame height, how hot the glass feels on the outside of the candle and of course if it has fully cured two weeks, the scent throw of the candle.


After the first burn, and during the last moments of the burn cycle I evaluate several things. First, how does the melt pool look? Is it edge to edge? If not, how much wax is left on the glass? Is it in just a few spots? Is it less than 1/8"? If so, the first burn is promising and it appears my wick is correct. If there is more than 1/8" all the way around the jar, I would likely replace the wick using one size larger the next test. If it is correct, I wait at least 6-8 hours and repeat the process. I am also of course in this time evaluating the scent throw (Specific to the diameter jar I am making of course). I will burn 4 full four hour burn cycles exactly like this before determining if the wick is indeed correct. 

With each test burn I check the following:

What is the length of the charred wick? Be sure to always trim it before each burn. If using a paraffin wax, it should be 1/4" if using soy, 1/8".

How deep is the melted wax against the glass? It should be at least 1/4" but no more than 1/2" for both optimal scent throw and safety. 

What is the height of the flame at the beginning and

end of each burn cycle? This you will read more about with the ASTM standards below. I like mine to be around 1/2" and just a hair over 1" at a maximum at the end of the burn cycle.

Did the melt pool reach from edge to edge?

Was there any smoking at all? Dancing flames?

Was the scent throw poor, good, great or outstanding?

 

If indeed based on the four test burns my candle is performing to my expectations I then move on to burning the rest of the candle fully to be certain that the life of the candle burns as well as the first four burns. This is not really something that should be skipped. It is a fire, you are placing it in someone's home. Safety First!

Below are the ASTM fire safety standards for testing candles. Once you have your candles burning to what you feel is correct, evaluate it using the exact standards as outlined below:

Per the ASTM, this is the standard for test burning candles. Every person/company testing should use the same criteria without exception.

F 2417- 09 STANDARD SPECIFICATION
FOR FIRE SAFETY FOR CANDLES

•Burn Test parameters:

– Candles burned in 4-hour burn cycles until end of

useful life except tea lights and gel candles

– Wicks to be trimmed to manufacturer’s label instructions

– Burned in laboratory with minimum draft

– Laboratory temperatures between 68°F to 86°F

– Candles spaced a minimum of 20 cm apart

– Flame heights observed at periodic intervals and recorded at the end of each burn cycle

F 2417- 09 STANDARD SPECIFICATION
FOR FIRE SAFETY FOR CANDLES

•Maximum Flame height requirement

– UP TO 3 INCHES (MOST CANDLES)

– UP TO 3.75 INCHES (CERTAIN RELIGIOUS CANDLES)

– Candles intended to be burned outside are exempt

• No secondary ignition

• No container failures

• For pillar candles no flame impingement of flame on the supporting surface at end of life

F 2417- 09 STANDARD SPECIFICATION
FOR FIRE SAFETY FOR CANDLES

• STABILITY

• Initially candles must remain stable when tilted to 10* off level

• Tilt stability of candles while in test
– “BURNING CANDLE SHALL NOT TIP OVER DURING

BURN TESTING” WHICH APPLIES TO FREESTANDING

CANDLES ONLY

I hope that this has given you all a bit more insight on test burning candles. It isn't something that should ever be skipped. Your testing now for safety of your product will prevent possible fires in the future!

Happy Candlemaking!
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