When working with shea–based formulations, you’ve probably noticed a dusty, grainy layer show up sooner or later.
This layer - called bloom - forms when fats recrystallize on the surface, and it can ruin your product’s look and feel, whether you’re making body butter, lipstick or lotion. So what triggers bloom, and how do you stop it for good?
Why Crystallization Makes or Breaks Your Product
Every time your formula cools, the melted fats start to solidify. As they do, fat molecules cluster into tiny nuclei that grow into crystal networks. Fast, even crystallization creates a smooth, stable texture. Slow or uneven crystallization makes bigger, irregular crystals—and that’s exactly what you see as bloom.
Temperature swings anywhere along the supply chain, from your cooling tunnel to a hot shipping container to a customer’s bathroom, give the shea butter a chance to melt and recrystallize. Each melt and reform cycle is an open invitation for bloom to appear.
The Liquid Phase Effect: Rapeseed Oil Vs. Fatty Alcohol
Shea butter’s high melting triglycerides form strong networks that risk instability unless blended with the right liquid phase. Rapeseed oil, itself rich in triglycerides, sparks rapid nucleation and many tight, tiny crystals, giving firm texture and minimal bloom. By contrast, octyldodecanol (a fatty alcohol) slows nucleation, producing fewer, larger crystals that feel softer but are more prone to blooming.
Three Steps to Banish Bloom
Eliminate bloom by combining smart ingredient choices with controlled processing:
- Choose base oils carefully. Favor triglyceride oils (rapeseed, sunflower) for bloom resistance. If a softer feel demands fatty alcohol, offset the risk with the controls below.
- Enforce fast, uniform cooling. Drop quickly to your target temperature (e.g., 18 °C) to lock in tiny crystal formation. Avoid slow temperature shifts that let crystals overgrow.
- Stabilize before filling. Hold at room temperature (≈ 23 °C) for 24–48 hours so crystals convert into their most stable form. This resting step prevents later crystal reorganization and surface bloom.
Your Bloom Prevention Plan
Review your formulations to identify current base oils and cooling rates; run a crystal size check on a production sample; trial a small batch of shea butter blended with rapeseed oil under rapid cooling and a two day resting period, then compare bloom levels to your standard.
The above actions - purposeful ingredient selection, rapid cooling, a solid resting period, and basic crystal monitoring - will ensure your shea butter products stay fresh, smooth, and bloom-free.
If you want to learn more about the liquid phase’s impact on shea butter crystallization, read the full scientific article
