Why Are My Soy Candles Rough On Top (How to Fix)

If you work with soy wax, chances are you’ll end up asking yourself…why are my soy candles rough on top?

Before you get too frustrated, know that rough tops with soy wax are very common and part of the process when making soy candles.

Below, we’ll cover why rough tops happen and what you can do to achieve a smooth top for your candles.

What Causes Rough or Bumpy Tops on Soy Candles?


Soy wax is polymorphic. In other words, soy wax forms crystals over time. The structure of these crystals can be influenced by temperature, air, and the cooling process.

Ideally, this crystallization process will lead to the smooth tops you’re looking for, but that’s not always the case.

These crystal structures can give off a rough, bumpy texture if conditions aren’t right.

Let’s look into what upsets the structure of these crystals leading to rough or bumpy tops.

Cooling Process

Crystallization is a natural process that begins to form in soy wax as it cools and solidifies.

The cooling process will determine whether these crystals appear smooth or rough.

If the wax cools unevenly, too quickly, or too slowly, the candle’s surface can appear rough and uneven.


Temperature is one of the main causes of rough tops.

The temperature of the environment you’re making candles in and the temperature you pour the wax will impact how your candle solidifies.

Trapped Air

Trapped air within the wax rising to the surface may cause an uneven or bumpy top.

Air bubbles may also lead to other problems like cracks or sinkholes.

Why Are My Soy Candles Rough on Top After Burning?

You may have noticed that your once smooth soy candle has turned into a rough and bumpy surface after you burned the candle.

Don’t be alarmed.

A rough top after burning is a natural occurrence for soy and is a sign that your soy candle is indeed an all-natural soy wax.

After you have burned the soy candle, the melted wax will cool and solidify inconsistently, leading to a rough top.

There’s no need to fix anything here, but if you’re selling, it’s always good to educate your customers about why this is happening and use it as a selling point as proof you’re using authentic soy wax.

How to Prevent Rough Tops on Soy Candles

Prevent Trapped Air

Don’t stir vigorously. Gently stir the wax to avoid creating air bubbles.

Gently tap the container to release air bubbles.

Pour slowly to prevent air bubbles from forming.

Adjust Pour Temperature

Record your pour temperatures and the temperature of your candle-making environment.

Start with the recommended pour temperature for the wax you’re using and adjust in +/- 5-degree increments.

There are mixed recommendations as to whether you should pour hotter or colder, which is why testing is so necessary, especially for tailoring the process for your environment, which will impact your ideal pour temperature.

Preheat Containers

Preheat your containers to promote an even cooling process.

Preheat containers in the oven at a low setting for 2-3 minutes or with a heat gun on the lowest setting.

Stable Cooling Process

Space candles at least 4 inches apart while cooling so they don’t interfere with each other’s cooling process. Once they have completely cooled, you can cure the candles stacked next to each other to save space.

You can also test cooling the candles on a rack. A cooling rack will prevent a solid surface from pulling heat from the candle and causing parts of the candle to cool faster than others.

Test Fragrance or Any Additives

To eliminate all variables, test making a candle without any fragrance.

Testing without fragrance will establish a baseline for you to know whether or not the cause of your rough tops is from your candle making process or an additive you’ve added.

Vanilla and some essential oils like lavender can cause rough tops. You can try testing a different pour temperature or look for alternative fragrances in this scenario.

Soy Wax Blend

Blend another wax with soy to help offset the common issues associated with 100% soy wax, like rough tops.

Paraffin works great, but if you want to stay all natural, you can blend soy with coconut or beeswax.

Wax suppliers will sell soy blends to help stabilize the crystal structure of soy wax and prevent rough tops.

How to Fix Rough Tops on Soy Candles

Repour Wax

When making candles, set aside extra wax in case you need to fix imperfections.

To repair a rough top, pour an additional layer of wax to cover the candle’s surface and fix any imperfections.

You only need a thin layer of wax to cover the imperfections.

Heat Gun

For minor imperfections, you can use a heat gun.

Use the lowest setting and, in a circular motion, melt a thin layer of the candle’s surface to fix the imperfections.

A heat gun is a great tool to not only fix imperfections but help prevent them as well, for example, by preheating your containers to avoid wet spots.