How to Perform Candle Testing
Candle testing prior can avoid a lot of troubleshooting later on. Make this part of your candle making process. Learning what candle performs better will help you get the most from this craft.
To perform candle testing properly you make candles that represent what you would be selling. The test candle is made using the jar, wick, and fragrance that is selected for use. The wick is monitored for burn performance and documented to validate that the wick will adequately deliver the fuel needed to produce a proper melt pool. The melt pool vapor will be a means for evaluating the hot throw from the candle.
Always practice good safety first. While it is not the law, you would not do well in a court of law without evidence that you did everything you could to make a safe product. Your candle making business relies on word of mouth reputation and repeated business. Testing your candles’ performance is how you can measure your customer’s satisfaction. Not everyone will give you feedback and if they do it is usually negative or an angry customer.
Candle making is a special process. You do not know the quality of the product until after it is made. Verifying the quality requires burning the candle and it is no longer suitable for sale. These are the candles I keep for myself. If need be I repair or rework them.
I NEVER SELL CANDLES THAT HAVE PARTICIPATED IN TESTING. I once re-used a glass jar and did not realize that the stress from the heat caused small fractures. On the second use, the glass broke spilling wax everywhere.
Initial Candle Testing
All combinations of containers, wicks, waxes, colorant, additive, and fragrance oil should be tested as well as manufacturing processes. If you are a beginner, start with 4 to six fragrances and choose 1 style of a container in 1 size. Take this one step at a time. When buying supplies, buy from a candle supply company so that you get support.
They know their products and can help you match up what you are buying. This way you start with something close and are not going in circles. If you buy a starter kit, the testing phase should be done for you.
If you change containers, you have to perform another test. If you change fragrance oils, you have to test. If you change the fragrance load from 8% to 10%, you have to test. You have to test all of the candle combinations. If you change suppliers, you have to test.
Manufacturing Candle Testing
Once you are in production, determine a sample size that you are comfortable with. Let me clarify this. You should be pulling a candle from your product line at least 1 in 100 candles you make and perform a candle burn test. You should vary your choice so that you are spot-checking your results. You should be documenting this in your log. If you are a candle lover, and probably are, document your burning. Label it. Take a picture.
Inspection Records for Candle Making
On my resource page, there is a printable pdf for a label and a log for candle testing. If you cannot make stickers, tape the label on. You should record your findings on the log and keep these records. This is proof that you know how your candle performing. This testing phase can give you a guide for each time you make candles. From this, you would develop your recipes. Before you can test candles you have to make some candles.
Making Test Candles
Test candles are of no value if they do not represent what you plan to manufacture and sell. To get started you only need to make 1 version of the candle and let it cure for 3 to 4 days. You can make a sorter candle as to not waste as much product. If you plan on heating the wax on a double boiler system and pouring from a metal pitcher that is a manufacturing process.
If you switch to a presto pot or use a larger melting pot you have changed your manufacturing process and need to spot test. Not much usually changes, but I had an issue controlling the cooling temperature when I went to larger batches and had issues with cratering.
- Make a candle as you normally would and let cure.
- Before lighting smell the candle and not the cold throw.
- Label the candle with the date, start time, wax type, wick, and fragrance oil. Log the information.
- Place the candle inside another container (I use an old cake pan), do not leave the candle unattended, and burn for 1 hour.
- Check the candle and make notes of the flame size, soot if any, wax pool, smell, etc. After 1 hour the candle should just be getting started with a shallow melt pool.
- Check the candle again after 2 hours. Check again as in step 4. Look to see if the wick has a mushroom or if it has self-extinguished. The melt pool should be less than ½” deep and should reach the edges of the candle vessel.
- Check under the candle to make sure the candle is not so hot it is burning any surface. The container will be hot to the touch but should not look burned.
- Take note of the hot throw in the room. Can you smell the fragrance around the candle?
- Check the candle again after 4 hours as above. The melt pool should be around ½” with a moderate flame and no mushrooming. The outer edges should not look burned.
- Gently blow the candle out. Make note of any tunneling or the appearance of the wax after it has cooled.
Candle Inspection Results
Small Flame Wick too small
Large Flame Wick too big
Flame Flares Air trapped, pour hotter
Wick Burns Out Wick too small or too much fragrance oil or wick clogged
Flame Sputters Water in Wax or wick clogged
Melt pool to shallow Wick too small
Melt pool deep Wick too large
Wick smokes Wick too large or room drafty
Wick tunnels Wick too small
Wax has craters Air pockets or poured to cool
Sinkholes around Wick Poured too hot
No smell before lit Not enough fragrance oil
No smell in room Wick too small or not enough fragrance oil
Top of the candle oily Too much fragrance oil or not cured
The flame still seems too high Try a different style wick, HTP vs CD
Candle Manufacturing Testing and Inspection
Make a suitable candle. Most of the manufacturing process for candles is common sense but sometimes that thought does not come to us until a mishap or someone points it out. We all know that a candle should never be left unattended but we get busy and forget about things. We have to assume that our customers have good intentions and can get distracted or simply do not follow instructions. We work with candles as part of our daily lives and experience more than they ever would. We need to keep this in mind when making candles.
As a practice, I make small to moderate size candles. I am careful to not make candles that burn deep into a container. This avoids overheating as the burn time is limited. A deep candle inside a glass jar gets very hot on top and has a greater risk of breaking. Taller candles are also top-heavy and are a greater risk of falling over. It is our job to reduce the risks of fire or injury as best we can and verify that as we continue to manufacture.
Purchasing from reputable candle supply sources and inspecting supplies. My primary candle vessel is a jelly jar a half pint and a pint jar made by Ball Corporation. This is what I carry for inventory 90% of the time. I also buy the glass jars without lids from the Dollar Tree. I use these when I want to make holiday candles or specialty candles. Very rarely do I use a different container.
Pick glass containers that are heavy and suitable for heat. Containers can reach up to about 150 degrees. If a container is marked on the bottom not safe for microwave or not dishwasher safe, stay clear! I have used wine glasses. I made sure to go as small as I could with the wick size as to not overheat the glass.
Before using any containers, check for fractures, cracks, splits, or chips that could propagate into a crack. If you are using tins, make sure seams are sealed or buy seamless tins.
Check your wicks to make sure they are secure to the tab.
Check your wax bags, boxes, and your fragrance oils to damage to the containers. Store in a dry secure location away from heat and open flames. Keep the lids on when not accessing the products.
All products should be identified including where they came from and when they were purchased. Keep a receiving log including the cost for accounting. I give everything a batch number and reference this later when making candles.
Candle Manufacturing Process
Before I make candles, I assign an assembly batch number and document the containers, wicks, wax, and fragrance batches I used. This batch number could be put on the label. Currently, I do not, but maybe I should. In the event something went wrong I would be able to trace back to what I used for that candle. You would rarely need to but you never know.
Verify that the glue you are using is not prone to coming loose. The wick should stay firmly in place while your candle is cooling. I have found that wick sticks can come loose. Check your candles for wick stability.
If this is a problem, switch to hot glue or glue such as an RTV or E6000 craft glue. After your candles have cooled, check each one to make sure the wick is still centered. Do not use candles that have a wick off to the side. The container will become too hot and may break.
Clean the containers for any drips and recheck the glass for cracks or chips. Handling may have damaged a jar.
Trim the wicks to about ¼” and inspect the tops of the wax. If there are slight imperfections smooth with a heat tool.
Check the overall appearance of the candle, document your findings and it is ready to be labeled. Congratulations!
Candle Testing Tips
Sometimes we want to use unconventional containers or not listed or we are just not sure for whatever reason. What you can do to save on the wax and save some time is to make the initial candle with a place holder like a wick pin. You can also hold the initial wick in place without the wick tab. If the wick is too small or too big when it cools you can pull the wick out and push another in its place. When you have found a wick that is closer to what you think it should be go ahead and perform your regular test.
It is still important to burn the test candle for 4 hours as it should be manufactured. This will help speed up your testing if you need a more reasonable starting point.