Hello,i am a soap maker and air bubbles can be a problem so when i pour my batter into a jug with the oild i give the jug a couple of bangs first--then i mix the batter with the blender stick off and tap the blender again off,when i am ready to turn the blender on i slightly tilt the jug and put the stick blender on the side and turn it on,this i learnt from watching Anne Marie of Bramleberry Soaps,and dont forget to tap your mold with each layer.
Mine is shaped in such a way that burping it doesn't get all the air out. I try to get as much out as I can the way you describe, but with this blender it doesn't work.
I adore mine, and as long as I burp it (which is fairly easy to do) it doesn't give me bubbles.
https://www.amazon.com/gp/aw/d/B07DJLJFG6/ref=ppx_yo_mob_b_inactive_ship_o0_img?ie=UTF8&psc=1I also love the trigger mechanism for power/speed, and it has handled my abuse fairly well.
My mom has a KitchenAid for cooking, and my goodness! The air bubbles! I had no idea a burped stick-blender could produce bubbles so badly! You have my deepest sympathies if that's what you have.
ETA: Y'all, this is a thread for mini-blenders, I think we're hijacking. There are quite a few threads for blender recommendations we could be having this discussion in instead.
That KitchenAid is what I have. My mother bought it because of brand loyalty. She figured if it's KitchenAid, it's good. She decided she was going to make soap as a business, and then bought all her tools and supplies. Then when she realized how much work it is to run a soapmaking business, she gave me all her soap making things. So I didn't get to pick my blender, and she had no idea what to look for in a stick blender intended for soap because she still has never made any soap herself.
Back on topic...
I have some ideas regarding a mini stick blender. I think I could come up with something that would work but I would have to have one custom made, which would be expensive. Basically, it would have blades like a proper shear-type blender (instead of what is basically a propeller on the Norpro mixer), but with a solid bell without the holes a normal stick blender has. The entire thing, bell and all, would rotate so if there were holes in the bell, it would just incorporate air. Or, alternatively, solid flat discs above and below the blades to stop air getting in and to protect the container the mixer is used in. That would restrict the flow of fluids more though. However, a bell that spins with the blades is going to affect the fluid dynamics of the fluid flowing through the blades because the spinning bell will pull the fluid along with it into a spinning motion.
I have given this a lot of thought. I think the reason you don't see tiny stick blenders is because of the way they are made. A regular stick blender has a rotating shaft inside a non-rotating sheath, and it's hard to scale that down because it gets less sturdy the smaller it gets. Not to mention, harder to make, too. I suppose it might be possible to make a bell that attaches separately from the shaft, but I don't know how well that would work. There would have to be a safety mechanism to prevent people using it without the bell.
I am still thinking about it. I like the challenge of coming up with new things to solve problems. I will let everyone know if I come up with something.