>It is very hard to say whether this would have amounted to a
>significant part of any paleolithic diet; I am inclined to think
>not.  I've only tried this with wheat; I have no idea whether
>other grains would work better or worse.
>
Real spelt ( not the one crossed back with wheat) is closer to wild wheat
and is difficult to thresh by hand but not impossible. modern grains have
been bred to facilitate the threshing ( there is a variety of barley that is
as easy than wheat to thresh, the normal barley is not) rye is easy to fresh
too . I enjoye myself eating all thoses grains raw in their green stage but
the work involved limit the quantity that i am willing to thresh with my
hands. Nuts  in the shell can be eaten in bigger quantity than grains. i
have a friend here on this island who own a seed company  who have hundreds
and hundreds of  heritage  varieties of protein rich foods  from all over
the world ( sadly they are beans and peas, and grains). He is a good source
to learn about grains. he is growing varieties that are suitable for home
gardens that can be threshed without equipment.
He is himself using his feet to rub the grain,  inside a wooden box ,
against  small slats of wood nailed in the bottom
jean-claude