NGI Wax Blog

The Causes of Polymorphism in Soy Candles

Posted by Dr. Al on Nov 24, 2014 3:51:13 PM Comments

soy candle frosting and polymorphism

If you’re having trouble with “frosting” on the sides of soy wax candles, or perhaps with white, lumpy “cauliflower” or “cottage cheese” effects on top of your candles, a number of different factors could be responsible. Regardless of cause, these effects are the result of soy wax polymorphism, or the reorganization of the crystal structure of the wax.

NGI is uniquely qualified to address the issue of frosting in soy candles, because our EcoSoya wax is the only soy wax on the market that’s truly engineered to combat polymorphism with our EcoSoya molecular blueprinting process.

EcoSoya CB Advanced Soy and CB XceL are the two most advanced vegetable waxes in the world when it comes to resisting polymorphism in soy candles. However, even when using NGI’s most advanced waxes, it’s important to know the causes of polymorphism, and what you can do to decrease its occurrence in your soy candles.

What Is Polymorphism?

Soy wax polymorphism is a problem common to all soy waxes. It occurs when the soy wax forms more than one type of crystalline structure as it cools from a liquid to a solid. Polymorphism takes place in response to environmental conditions, as the soy wax seeks the most stable structure for its environment. The “frosting” effect is one of the most common forms of polymorphism.

The best way to describe frosting is to think of what happens to chocolate when you leave it in your car on a sunny day. The heat melts the chocolate, leaving a gooey mess in your cup holder. However, when it cools again, the chocolate has a whitish film on top instead of its former smooth, brown consistency. In fact, this frosting is chemically exactly the same as the rest of the chocolate - only the crystal structure has changed.

How Polymorphism Affects Performance

If you’ve ever eaten chocolate affected by polymorphism, you probably noticed that the change in crystal structure changed not only the appearance, but also the texture of the chocolate when you eat it. Likewise, a candle affected by polymorphism may not only look less pleasing, but may also congeal less smoothly after burning than would a candle with a uniform consistency.

It’s important to test for polymorphism not only during the pouring and cooling process, but also the burn cycles of the candle; polymorphism can also occur when wax in the candle’s burn pool melts and re-solidifies with use.

Causes of Polymorphism

There are numerous conditions that can cause frosting or cauliflower top, which make these effects difficult to eliminate. As you experiment with different factors, be sure to follow the scientific method and change only one variable at a time so you can isolate and fix the cause of polymorphism in your candles.

Common causes of frosting and cauliflower top:

  • Pour temperature
  • Cooling room temperature
  • Candle storage temperature
  • Humidity
  • Fragrance, dye, and other additives
  • Wax composition (if you’re blending waxes)

Soy wax crystals are especially sensitive to temperature changes, so if you’re having trouble with candle frosting, start by adjusting your pour and cooling temperatures. Consistent temperature during the cooling period is particularly critical to proper crystal growth.

Incompatible fragrances can also cause frosting or cauliflower top in your candles, resulting in a lumpy surface, poor adhesion, small-diameter burn pools, and even poor burn quality. If any of these issues are occurring with an EcoSoya soy wax, please use our Fragrance Program to make sure your fragrance is compatible with the wax you’re using.

For more information about polymorphism and other issues, visit our Resources & Support database.

As you’re working to improve any line of soy candles, remember to follow the scientific method, changing only one variable at a time. When you follow this simple process, you can know how any single variable affects your candle’s performance. 

The first and easiest step in combatting polymorphism in soy candles is to start with a soy wax that’s engineered to combat polymorphism, like our EcoSoya CB Xcel and CB Advanced Soy waxes.

You still have to use appropriate fragrances and control temperature and other variables - but overall, you’ll get better results more easily with EcoSoya’s best waxes.

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