I try look around on the Internet but where can I find the scientific evidence that we can only…

I did try to look for it but the articles came up have nothing to do with fineness bur rather flavours . But thanks for the help. Will continue looking for it.

If your question is ‘can the human tongue detect particles finer than 20um?’ – then the answer is yes. I can not point you to a scientific paper that has been published (although i’m sure it’s out there) – but i’ve done the work myself. Not everyone has the same ‘limits of detection’ – but for most people, once you go finer than about 15 or 16 um, they lose the ability to detect individual particles.