I would like to use salt that is ground to a very fine / small grain size.
What do I look for in a grinder to achieve this? Is there a grain size?
I have seen coffee grinders, but their grain output is much more coarse than what I want to achieve.
Is there a specific kind of grinder that will do the job for me?
You should consider whether sourcing finely ground salt would be easier than sourcing a high-quality grinder. In the US, "popcorn salt" is available and is an extremely fine grind. A grinder capable of a smaller grain size than that would likely be fairly expensive and difficult to source as a consumer, to say nothing of the humidity-controlled environment you'd need to use it effectively.
Though, for small amounts, a decent ceramic mortar and pestle is capable of grinding salt arbitrarily finely (until it absorbs water and clumps).
You can use any electric coffee or spice grinder to get an arbitrarily fine salt grind. The longer you grind it the finer it will get, and since salt is not very tough to grind it doesn't take long at all especially if you start with standard table salt which is already pretty small in grain size.
I use a cheap spice grinder to turn salt into a fine powder for using on popcorn.
I've only ever known one properly adjustable salt [or pepper] mill.
Most of them just work on how tight you fasten the knob on the top.
For the past 25 years or so , I've had one made by William Bounds, a US company, though I got mine straight out of a UK department store.
The knob doesn't dictate the grind, there's a dial on the side, Coarse, Medium, Fine. Looking at their web site - which looks like something from the early 90s & is a nightmare to navigate - they seem to do ones with 5 levels of adjustment now.
I have no way of knowing whether you'd consider the 'Fine' fine enough. I use mine on coarse, for that crackly top presentation.
Here's a link to how their mechanism works
Just to note that, though I have a pair of these, I don't use the other one for pepper, I don't think it's particularly great at that; it's not fast enough for me - though I see they now make a high-output 'pro' mechanism [bottom of the linked page] which I'd be tempted to try.
I also must add that I don't spend a lot of my time researching salt & pepper mills - so there may be many things out there that have completely eluded me over the years.
