October through May
During this season, flour is not infested under normal circumstances. However, it is praiseworthy to sift the flour during these months.
A “Pela-matic” motorized sifter of 70 microns can be used. As well, the sifter known as the Bnei Brak Sifter is approximately a 70 micron mesh, and may be used. (Note: the higher the micron rating, the finer the filter.)
June through September
Could be infested. Should be sifted
It is highly recommended that flour be sifted during these months. See details above, under, October through May.