Being in the candle industry since 1997 I like to skim the internet for questions or ideas people have related to candles. One topic that comes up repeatedly is whether storing candles in the freezer before lighting them will cause them to burn slower. Why does a slower burning candle matter anyway? The idea is to make it last longer in order to save money on candle purchases. We decided to put together our own experiment and see if freezing candles really will make them burn longer.
Thought Behind Freezing a Candle
Before getting into how we did our experiment, perhaps I should run through the basic thought process as to why freezing a candle might make it burn slower. The wax of the candle is the fuel for the candle flame. The fuel needs to be in a liquid form in order for the flame to use it. If the wax is frozen than it will turn from solid to liquid slower, therefore, not be used up as quickly as room temperature wax. So freezing the candle should be a good idea, right?
Setting Up the Experiment
We set up the experiment using a few different candle types. We used 2 sizes of pillar candles, one was a 2″x3″ and the other a 4″x6″. We also used votive and taper candles. One of each candle size and style was placed into the freezer and a matching size and style was left at room temperature. We drilled a small hole in the side of the taper in freeze so we could measure the core temperature throughout out test. Both tapers were weighed and each was 68.6 grams. We also had 2 digital “instant read” thermometers on hand and a stop watch.
Before going further I need to preface the next part of the experiment with a little explanation. I had mentioned at the beginning of the article that I have been working with candles since 1997. My job is actually in a candle factory making candles. Many times when a pillar candle would not release from a mold we would put it in a freezer, which helped. However, there was also potential for a negative result. So before doing the test I already knew what the outcome for the pillar and votive in the freezer would be.
Ok, back to the experiment. Based on my knowledge of how the pillar and votive would react to being in the freezer, I planned on checking the candles every 15 minutes.
At the first 15 minute mark I went to check one the candle in the freezer. What I found was not a surprise. Both the 2″x3″ and 4″x6″ pillar we cracked, or rather, shattered. I squeezed the 2″x3″ and it completely fell apart. Had either of these pillar candles been lit, the liquid wax would have drained out through the cracks and all over the place. This would actually have made them burn much faster than the ones at room temperature.
The taper candles was not cracked and ended up being left in the freezer overnight. The following day we took and taper our of the freezer and noticed it had not cracked. This gave us an opportunity to do the burning time test. Before lighting the taper candles we took a quick reading of their core temperatures. The one from the freezer was at 33 degrees Fahrenheit, the other at room temperature which was 69 degrees Fahrenheit. We lit each taper candle and left them burning for 1 hour.
After the 1 hour we came back to check on the tapers and take a reading. The initial observations were that the flames on each candle were identical in height and the amount each candle had burned down looked even. We took another core temperature reading and noted that the candle from the freeze had reached 65 degrees. The room temperature candle still was 69 degrees. We also took a temperature reading of the liquid wax below the flame. Both candles had a liquid wax temperature of 162 degrees. We left the candles burning for another hour.
After the 2nd hour we repeated the measurements take after the first hour. Again both candle flames looked identical in height and each candle had burned down equally. The core temperature of the frozen candle was now at 69 degrees which matched the room temperature candle. The liquid wax below the candle flame on both candles was still at 162 degrees. Since the candles were both reading 69 degrees at their core, there was no more benefit to continue the burn test. Both candles would burn at the same rate from this point on. We extinguished the flames, let the liquid wax harden, and re-weighed both tapers again. Each of the tapers weighed 26.2 grams.
Putting the pillar and the votive candle in the freezer did not make them burn longer, in fact it had the opposite effect, damaging them so they could not be used. The taper candle from in the freeze showed no signs that it burned longer than the room temperature candle either visually or by weight. Why did freezing the taper not work? I’m glad you asked.
The heat at the base of the flame from a candle is about 1000 degrees Fahrenheit and near 2000 degrees at the top. When you light a candle, the wax around the wick is instantly effected by that high heat. The 40 degree gap between a room temperature candle and a frozen candle is erased nearly instantly when presented to the 1000 degree candle flame. The heat from the flame affects the wax closest to it creating the liquid fuel it needs on both candles. In the mean time, the rest of the frozen candle warms up to room temperature slowly until it is needed by the flame.