Q. Hello Rabbi Bartfeld,
Since most wheat in America is Winter wheat (which is always Yoshon), when one wants to eat any product that has flour, one can rely on the majority. Furthermore, since it is very difficult to find out exactly where the flour is from, one does not need to investigate. This seems to be Rabbi Miller’s opinion. I would like to confirm, that indeed according to Rabbi Miller, one who is makpid on Yoshon, can have any flour based food based on Rov (besides pasta which is made from Durum flour).

A. Horav Shlomo Miller’s Shlit”a opinion is that indeed if there is a majority of grain marketed in that area for that particular use (e.g. bread, cake, cereal) that is yoshon (lit. old – before Pesach produce), it would be permitted. Although, chodosh (new produce) is a “dovor sheyesh lo matirin” since it will became eventually permitted and should not become nullified, many Poskim maintain that when not mixed “betraruvos,” we do follow the majority (Chavas Daas, Pri Megodim Y.D. 110, Pischei Teshuvo Y.D. 102: 1, Igrois Moishe 8, Y.D. 46, et. al.) Besides, the Rov maintains that since most of the wheat produce is chometz, it is not to be treated as a “dovor sheyesh lo matirin,” since if not sold before Pesach, it will become prohibited.
However, as you mentioned there are many variables and some could actually be investigated. The Rov suggested you contact Rabbi Y. Herman from Yoshon.com at info@yoshonnetwork.org or call 513-800-1957.
Behatzlacha.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a