Hi Sugarmamabakeshop! Great idea on using the spice grinder to take care of the rice milk powder, vanilla powder and cane sugar! Ok, I've recently learned that we perceive graininess on our palates with anything larger than 20 microns. That's why this chocolate is somewhat grainy. A spice grinder will grind up things nice and small, but it's nowhere near 20 microns. Commercial chocolates use processes called conching and refining to get the particles this small.

I've looked into home chocolate production and the only thing that will grind particles smaller than 20 microns is an Indian spice grinding machine called an melanger (pronounced "me-LA-jie". They run just shy of $500 so it's going to be awhile before we're producing stuff rivaling artisanal chocolate.

If you want the chocolate to be more thick and viscous you could add more non-dairy milk powder- but then you'd have even more graininess on the palate.