I am looking for info on an unusual rye "old dough" starter...my 75 yo dad (born in Hungary/Slovenia) recalls his mom starting her rye breads with a hunk of old dough that was permitted to dry out.  A day or two before she was ready to bake, she would crumble this dried dough into water and once it started to form a "sponge" she was ready to bake.

I will have to check with him if the bread was 100% rye, but I suspect so...they were poor and wheat was hard to come by.

 I have looked in various books (by no means exhaustive, yet!) and the closest I've seen was Nancy Silverton's liquid starter which can be dried into flakes.

Anybody?

thanks,

Paula