I want to make nut butter from soaked cashews or soaked pepitas. I am wondering what type of machine will get the smoothest product?
I am currently using a food processor which is great for cashews but I'm wondering if I can do better. Other possibilities include a blender, nut butter machine, and some type of grinder (perhaps a wet grinder?).
Any machine that can reduce the nuts to very fine granules should do the job.
Wet grinders given there’s enough liquid/fat content in the nuts should do the best job. However that might not always be the case. Special high powered blenders (such a blendtec) with a purpose designed jar (like a twister jar) would generally provide more reliable results.
To make smooth nut butters you need a melanger or a wet grinder. If you have a boatload of cash to spend, this will do the job nicely. Otherwise, you can get in the game for under $200 US with this wet grinder. You will never get a smooth product with a food processor, or even a high speed blender. There will always be some perceptible grit with those tools.
I haven't used grinders (and I don't know which home grinders are suitable), but a good machine for this is a masticating juicer. Even though it is called a "juicer", it only separates the juice from the pulp in a late step, by pressing the whole mousse through a fine screen. The models sold nowadays come with a part made of smooth plastic which replaces the screen, and all the "chewed" stuff falls out through the juice hole instead of being separated.
Because of the squishing action of the cylinders, it gives you a smooth result where all bladed products end up with small pieces.