Fixing Rough Tops (Soy Wax)
Rough tops. Bumpy tops. Maybe you call them cauliflower tops, but they’re all the same. An ugly, disfigured, not-smooth-at-all candle top, and it’s frustrating!
These candle issues aren’t hard to diagnose, but they’re terribly difficult to treat, unfortunately. As candle makers, we strive to create products with powerful scent throw, extreme safety, and smooth tops. Soy wax is often a disruption on your way to achieving the dream.
But it’s okay. If you want to find out why you have rough tops and want to take control of the situation, you’re in the right place!
Causes of Rough Tops
Before jumping in it’s important to remember the background of soy candle wax.
Soy wax is polymorphic, meaning it crystallizes in response to temperature changes and time. Generally speaking, the more time it has during a temperature change is a larger window for crystals to form.
This behavior usually happens as the wax changes state from liquid to solid, like when you’re pouring it into a container, for instance. Crystals are responsible for frosting in soy candles too.
Generally speaking, soy wax begins forming solid crystals as soon as it begins cooling when you’re making candles. If you heat your wax to 185 °F and let it cool to your pouring temperature, crystals will form in the wax during that time. The more time that passes, the larger the crystals can become (especially if you’re not lightly stirring to maintain constant temperature throughout the blend).
If conditions are disagreeable enough, the cooled candle’s top will end up looking rough as the rest of the soy wax solidifies amidst the irregular crystalline structure.
That’s the long way to say wax cools irregularly and randomly before finally hardening.
The same effect occurs after you burn a soy candle – the top will not finish perfectly smooth, even if it had a full melt pool. They’re also be some frosting on the melt line where wax hardened irregularly.
Treatment
Treating rough tops is possible after they’re created, but taking measures beforehand is more cost-effective in the long run.
Post-Pour
Getting rid of existing rough tops on soy candles potentially creates more problems than it solves, but it’s not impossible.
Apply constant heat with a heat gun to the affected area, melting a depth of approximately 1/8″ across the effective width of the container. When you finish, allow the top to cool evenly in open air. If you place a lid or cover above the melted surface, risk of irregular cooling increases (hello, crystals!).
Candles being actively used shouldn’t have any treatment because soy wax hardens and cools irregularly. It won’t affect performance and cosmetic issues don’t bother your customers as much as it bothers you.
Preventative
Your product line (and mental health) will fare better in the long term if you can stop disruptive crystallization before it happens. Here are three strategies to employ.
Refine Your Temperature Management Plan
We’ve talked about building a process blueprint before. Understanding how the environment affects your candle making process is critical to outputting beautiful, consistent candles.
Your Temperature Management Plan describes the strategies and temperature ranges you’ll use for a specific candle design. You’ll want to check how your soy reacts to different temperatures.
The community often shares their experiences with heating, cooling, and pouring temperature of the wax, but they often leave out the other half of the story – the ambient room conditions.
Candle wax isn’t operating in a vacuum, rather, the environment around the containers and workspace impact pour quality too!
- Room temperature
- Humidity
- Draftiness
The treatment strategy is simple – take a lot of notes and observe how your candle behaves. Some people swear by pouring your soy at higher temperatures while others claim you shouldn’t pour until it’s a milky, cloudy mess.
The truth is either strategy can work, but you have to learn if your process fits into either theory. Your climate and time of year affect quality too, so continuously test and figure out works and in what conditions it works in!
Starting points:
- Pour as cool as possible (cloudy), but lightly stir as soon as you mix fragrance oil the entire time (without introducing air) until you pour. Vary the rate of cooling in the pour pot each time and see how it impacts your candle.
- Pour as hot as possible and cure in varied-temperature areas. Try a pre-heated oven or a cool basement.
- Pour at the manufacturer-recommended temperatures, varying the pour temperature by 5 degrees either way to see how it impacts quality.
When you find out what works well, duplicate that process to make sure.
Rule Out Additives
The truth is that some fragrance oils impact soy quality more than others, occasionally beyond any candle makers ability to prevent rough tops.
How would you know if the fragrance oil is the culprit? You have to know that your process works for a bare wax. Building a design pipeline that starts with perfecting the naked wax is the quickest way to scale your work and identify problems with additives.
Use the first strategy mentioned without any fragrance oils or dye to lock down the wax properties.
Blend With Other Wax
Soy is fickle, but paraffin and coconut offer stability and resistance to some of soy’s problems. If you can pivot off a pure soy wax candle, consider blending with another wax type to harness the other properties and cut down on the soy-ness scale.
Be careful if you’re adding a lot of different commercial waxes together. Sometimes their polymers and additives conflict and become detrimental to your design. Just make sure to test.
Everything added impacts everything added.
Final Recommendations
Don’t be discouraged by your soy wax behavior. It’s part of mastering the wax and everyone deals with it. Even the great soy wax makers of our time, like P.F. Candle Co., had to figure out how to overcome polymorphism to build an incredible candle line. With enough persistence, consistency, and attention you can too.
Unfortunately too is that soy wax can vary from lot to lot. Even if you perfect your tops on one, there’s no guarantees your process will work in a different lot (also part of soy wax history).
Inconsistencies are why it’s critical you build an algorithm for your Temperature Management Plan to enable you to move quickly and identify small changes in wax behavior without breaking the bank or losing too much time.
And here’s the other reality – soy wax candles will be bumpy after use anyways. Nothing to do about that. Most of this triage is meant to provide a smooth top appearance for sales and initial admiration. Rarely do rough tops affect the candles ability to burn.
And this is good news for candle makers – customer’s often don’t care about the physical make up of their candles while they’re using them so long as they are safe and smell like they want. Candle makers are our own worst enemies, but pursuing perfection against an irregular and random property trait of soy wax is a quick way to disappointment.
Focus on safety, process, and performance first. Then refine for everything else. And above all – enjoy the show!
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