From what I understand, it really does not matter, as long as it is just sodium hydroxide. Food grade is used for olives and pretzels, etc. A lot of people use sodium hydroxide drain cleaner, which is not food grade. HTH
I purchased the food grade lye from AAA and was very pleased. There was a difference in appearance compared to the Rooto lye I was using.
The beads were a bit larger and less clumping involved. I bought the food grade because I wanted to make sure I was getting 100% lye. Not to imply that the technical grade isn't. You will save a few bucks. My favorite lye is BrambleBerry's (no beads!) But, too expensive.