Shailah of the Week by Rabbi Zvi Nussbaum
Rabbinic Coordinator, Kosher Hotline Administrator for the Orthodox Union
Some flour mills process exclusively winter wheat. These mills are relatively easy to certify. All that is necessary is to ensure that the enrichments and barley malt added to the flour are yoshon all year round.
Mills that mill spring wheat are more difficult to certify. Such mills will typically hold off from purchasing the new crop of spring wheat for as long as possible, allowing for continued yoshon milling through September, but eventually they will receive shipments of chodosh. In this scenario, silos of yoshon flour are certified as yoshon before any chodosh enters the plant.
Once a mill is “contaminated” with chodosh, it needs to be “cleansed” before returning to yoshon production. A wet cleaning is not possible for a mill, because this would cause the flour to gum up and get stuck everywhere. Instead, the cleansing is performed with significant flushes of yoshon flour. The flushes are performed until calculations show that no detectable level of chodosh is present in the mill.