An immersion blender is an essential bit of formulating equipment; it’s the high-shear mixer of choice for home makers. Immersion blenders blend without whipping lots of air into our products; it’s a purée action, not a whipping action.
I do not recommend the sort of thing you’d use to whip up whipping cream or cream together butter and sugar for making cookies instead of an immersion blender. Mixers like that are designed to incorporate lots of air into our formulations, and that’s not the aim if a formulation calls for an immersion blender. Using a whipping device rather than a blending device can create a product that will collapse as it ages (it can also make a big mess)
My go-to blender for years as been the Braun one seen in the above photo. I picked it up for about $5 at a thrift shop over ten years ago and it’s been great, but I wouldn’t go out of your way to source that exact model. The head of this blender is 6.6cm across, and it tends to fit in 400mL (and up) beakers. This blender works for batch sizes 100g and up; I’ve made up to 1kg of lotion and ~2kg of soap with it with no isssues.
I have a Dynamic MiniPro with a homogenizer head and I don’t recommend it. It’s very heavy, cost hundreds of dollars (most of the cost was the homogenizer attachment), and I rarely use it.
As of December 2022 I also have a Bamix immersion blender, and I love it! The best part about it is the size of the blender head (5.6cm across); it’s small enough to fit in a 250mL beaker, so I can make smaller batches (down to ~50g [1.76oz]). Hooray!
I picked my Bamix up at a thrift shop; it looks to be the “SWISSLINE” model from the 1980s. Bamix still manufactures new immersion blenders and they look to be quite widely available through Bamix directly and through kitchen supply shops. You won’t need the beaker or the chopper/processor that come with some sets, but it is helpful to have the three different blades and the stand. I mostly use the “whisk” blade—the round disc with the little scoopy perforations. My mixer is labelled as 140W and is plenty powerful; modern Bamix mixers seem to start at 150W, so I’m betting any current model will work for you. (Not sponsored, but hey Bamix… if you’re reading this, I’d love to compare a modern one to my vintage model! 😉)