What does air bubbles in lotion/creams look like?
If you’ve ever packaged up a lotion in a clear bottle and noticed lots of air bubbles appearing up against the side of the bottle a day or two later, that’s air bubbles. Or perhaps you’ve made a thicker cream, you package it up, and it collapses and dramatically reduces in volume in the following days—that’s also due to air bubbles.
Why are there air bubbles in my lotion?
Very basically, they’re there because you put ’em there during the blending/stirring process. The thicker an emulsion is, the easier it is to incorporate air as you mix it. Here are some tips to reduce the amount of air you work into an emulsion as you make it.
Make sure the tool you are using to blend the lotion is designed for puréeing, not incorporating air. If you’d use a tool in the kitchen to whip cream, do not use it to mix a formulation unless the goal is to whip air into that something. This is why we use an immersion blender (a tool designed to purée) for lotions, but electric beaters (a tool designed to incorporate air) for making whipped body butters and other whipped formulations.
If your immersion blender has interchangeable blades, choose one of the flatter ones. The flatter/lower profile the blade is, the less likely it is to poke up over the surface of the mixture you’re blending (which will blend in more air).
Stop blending the lotion while it’s still too thin to support air bubbles and switch to gentle hand stirring. I typically find a 40–60 seconds of blending (followed by near-constant hand stirring until the emulsion thickens up) is more than enough to create a stable emulsion.
If the emulsion is still very fluid/thin, it won’t be able to support any air bubbles—they’ll just float right out. Continuing to vigorously blend/stir a lotion when it has thickened up will incorporate air into it, and it’ll be able to stay there because the lotion has enough structure to support that air.
This tip is more important for thicker emulsions; if you’re making a thin body milk you can blend away to your heart’s content as the emulsion will never get thick enough to support air bubbles.
Keep the immersion blender head submerged when it’s running; don’t pump it up and down. If you feel like you need to pump the blender up and down, that’s a good sign your emulsion is thick enough that you should’ve stopped blending a while ago. Only use the blender while the emulsion is thin enough that it’ll circulate around the moving blades easily.
Similarly, don’t stir super vigorously one you switch to hand stirring—keep the emulsion moving, but if your stirring method looks like something you’d do to prepare eggs for scrambling, calm it down 😄
Make sure your tool is submerged in the emulsion as you’re blending. You need to be able to submerge the entire head of the immersion blender in the emulsion; if it’s poking up above the surface, that blade will be able to grab air and blend it into your emulsion.
Ensuring submersion is typically going to depend on 1) batch size, 2) beaker size, and 3) blender size.
The wider the head of your immersion blender is > the wider your beaker needs to be to fit the blender > the larger your batch size needs to be in order to submerge the blender head.
My Braun immersion blender is 6.6cm across. This wide enough that the minimum batch size that will submerge it is 100g (3.5oz).
My Bamix immersion blender is 5.6cm across; this is narrow enough that a 50g (1.76oz) batch will submerge it.
Posted in: Troubleshooting & Adjusting