I used to have a real problem with the lumps in the black mix. Even a nutri bullet blender didn’t get rid and I stopped using huel because of the texture.
Recently back in the huel game to help meet my training goals. I got 12 berry rtd and a bag of cinnamon swirl black.
The rtd went very quickly and I was dreading the black powder. I have however upgraded my kitchen equipment and now have a bamix blender which has completely changed the consistency of the drink. They are an elite cheffy machine and pricey (I used to be a chef so is worth it for me) but honestly the difference is night and day. This definitely marries up with the idea that the rtes are made with industrial equipment.
I can say that, for me, happily the bamix has cracked it. I get a smooth light airy mix that is actually pleasant to drink.
TIpps for solubility are: First cold water, then add powder,shake/blend, then add the rest of the water, shake/blend again. Store it in the fridge overnight. Maybe use some plant drink instead of water.
Or add powder not all at once but in multiple “steps”.