Please could you clarify the quantities of flour required (both d’Rabonom and De’Oreisah) for hafroshos challah in the given circumstances:
1. White flour
2. Whole wheat flour – is there a difference between whole wheat flour from chutz le’aretz which is more refined and whole wheat flour from Eretz Yiroel which is more course.
4. A mixture of whole wheat flours (one less refined and one more course) and spelt
2. A mixture of brown and white flour
The amount of flour for hafrashas challah is a measure of volume (2.32 liters), and not of weight.
For ordinary white flour, the weight comes to 1.6 kilos (this is the R’ Chaim No’eh shiur, and most people rely on it for challah).
However, the weight can change for other forms of flour, depending on their density.
The easiest way to measure the required amount is to take twelve 200ml (standard) full cups of flour, and weigh the result (more precisely, 11.5 cups and a little more).