4 Wick Testing Tricks You’ll Wish You Knew Sooner
Efficient wick testing is paramount to successfully producing awesome candles!
The main drawback of testing candles is the amount of time it takes, which increases the feedback loop of the ultimate question:
Is your wick properly sized for your candle to burn safely and perform well?
Every candle maker strives to meet these criteria, with safety taking the highest priority slot. Use the following 4 tricks to accelerate your wick testing so you can stay organized, stay accurate, stay within your thermal limits, and adjust quickly if you need to!
Tip #1 - Use An Identification System
No proper record keeping system is complete without some form of an identification system. Retail stores use a SKU for inventory management, but as a candle maker you need a system to connect your results to your records.
A good candle identification system should enable you to:
- Track what temperatures you melted, added, poured, and cured a specific candle at
- Recall the result of that specific candle’s wick test
- Tie any product in your inventory back your design and testing notes
These IDs let you track the life cycle of any candle design, that is, the “recipe” for that candle, from the cradle to the grave. More specifically, from the research and development to the final burn cycle.
In practice this means keeping some form of a database, which can be informal if that’s how you operate, with all the information about a candle tied back to one or more ID numbers.
Your system is completely up to you, but you can use the date-design-batch system as inspiration.
Date-Design-Batch ID
Using the date-batch identification system boils down to assigning an identifier to every unique design or batch.
For example, if you have a candle DESIGN that looks like:
- Wax: GW 464
- Fragrance Oil: Lavender, 6%
- Wick: CD 10
- Container: 8oz Glass Jar
we could assign that a DESIGN ID. The design ID has nothing to do with temperatures, conditions, or any batch-specific items besides fragrance load. It strictly refers to the ingredients going into the candle.
Let’s label the design ID #100.
Then consider the BATCH for that design, which you would record information about what happens when you apply the design, like:
- Room temperature & humidity
- Max wax temperature
- Fragrance oil adding temperature
- Wax & fragrance weights
- Pour temperature
- Wax information (lot number, supplier, etc)
- Fragrance information (type, supplier)
we could assign that a BATCH ID that ties the application of our design to an actual candle.
Let’s label the batch ID #1000
You may be asking, “why shouldn’t we use a single identifier for both?”
And you wouldn’t be unreasonable to question that. You can build your identification system however you want, but separating the design from the batch allows us to pour multiple designs from a single batch without worrying about how to distinguish each.
The final piece of the puzzle is the date of pour. Important for so many reasons. Let’s use a six digit format, yymmdd to label.
Combining everything together, our candle ID is:
201201-100-1000: date-design-batch
Research & Development versus Production Lines
Splitting the batch and design IDs works better when you’re in a research and development mode, testing out multiple wick sizes. In that case, you have one batch of wax going into multiple containers and wicks.
When you have a fully matured product line, you can usually assume a 1:1 relationship between batch and design, and consolidate them into a single ID.
Regardless of how you structure it, your system should allow you to pull any of your candles off the “shelf” and figure out what supplies went in to it, in what amount, and when.
Tip #2 - Weigh Your Candle Before Each Test
A candle wick consumes vaporized wax blends as fuel.
Quicker fuel combustion usually means a hotter candle system. Sometimes, capturing one additional metric during wick testing can help you spot systems that are burning too hot or too cool.
You can measure the weight of the entire candle, including the container (if there is one), before and after every test to find out how much wax your wicks consumed.
Rate of Consumption
If you divide the difference in weight by the time your candle burned, you can calculate how fast your candle is burning through the wax. Let’s look at an example:
You’re safety testing a container candle, and measure the weight before and after burning it for 4 hours, including the container weight.
- Candle Weight Before: 570 grams
- Candle Weight After: 556 grams
- Total Burn Time: 4 hours
You can calculate the Rate of Consumption (ROC) of the candle system with this equation:
ROC = (Candle Weight Before – Candle Weight After) ÷ Burn Time
In our example:
ROC = (570g – 556g) ÷ 4hr = 3.5 grams/hour
Technically, you could use this to estimate the entire burn life of the candle, but most container candles burn hotter further down in the container, with a higher ROC. But if you’re trying to find a rough estimate, you can calculate the burn life of a design if you know the wax weight in the container.
Wax Weight = Total Candle Weight – Container Weight
Burn Life (hours) = Wax Weight ÷ ROC
If our total candle started as 570g, and the container weighed 120g, and we calculate our ROC as 3.5 grams/hour:
Wax Weight = 570g – 220g = 350g
Burn Life (hours) = 350g ÷ 3.5g/hr = 100 hours
These are extremely rough estimates for the reason mentioned earlier, but the theory holds up. The best way to figure out your candle life is to burn through the entire candle, 4 hours at a time, and tracking how many hours it burns for.
Most candles will burn for a range depending on the burn habits of the users, but a 4-hour standard test from start to finish will supply you with an approximate estimate.
Tip #3 - Measure The Melt Pool Temperature
Wick testing requires you to track numerous different metrics, all which play a role in the candle’s success, and melt pool temperature is no exception.
Hot throw depends a lot on how well your wick compliments the fragrance note profile in the wax blend. It also requires good air currents in the room, but that’s not important for this point.
Top notes evaporate quicker than base notes, especially in hot conditions. If your fragrance oil has a particularly high range of top and middle notes, hot wicks risk burning off the aroma before it ever throws in your direction.
Candle wicks that burn too hot ruin a lot of otherwise good candles. So how does melt pool temperature factor in?
A melt pool contains melted wax mixed with liquid fragrance oil (duh), but it lives in direct heat of the wick’s flame. If it maintains a temperature profile that’s too high for that fragrance oil, the notes can burn off before they ever have a chance to go anywhere!
Sometimes this causes candles to smell really well at first but then peter off on subsequent burns for a while – the wax blend cooled to a solid despite losing a lot of it’s fragrance oil on the previous burn. After it melted again and traveled to the wick, there wasn’t any fragrance left to throw!
The “right” temperature for a melt pool depends entirely on the candle, so measuring melt pool temperature helps you find that sweet spot for your particular design.
Not to mention, understanding how your melt pool behaves only helps give your more context into when things go sideways and how you should react!
Tip #4 - Replace Your Wick, Not Your Candle, If It Fails
Not every candle comes out perfect.
If your design fails a safety test, or doesn’t smell as strong (or as good) as you desire, you might be inclined to toss it away and start over.
If you regularly cure for multiple weeks, this disruption can really set you back a ways. Fortunately, you can just replace the wick in place instead of re-pouring an entirely new candle!
Read this article with a video on how to replace your wick and save yourself a TON of time! Wick testing doesn’t always mean creating fresh candles when things go sideways. If you have an apple corer and some moxie, you can reduce your feedback loop a considerable amount.
One final note – if you switch out wicks throughout a candles lifetime, you probably don’t want to treat that as an acceptable Industry Standard Safety test, but it helps you figure out where you need to go.
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