What is the religiously obligatory method for paying the zakah on grains and similar items that are measured by volume and stored: is it to pay them by volume or by weight?

The Shaykh: If it were liquid, how would that be?

The questioner: If it were solid, would it yield more, or less?

The Shaykh: Less, because it contains air pockets. That is, if we take lumps of fat and measure them by volume, what would the result be, for example? Let us say one and a half kilograms. So, when you want to extract that one and a half kilograms as a liquid, it will be more, because the air pockets will be filled. The point is that whether by volume or by weight, the person obligated must know what is required of him. So, I gave an example earlier of wheat or barley. We weighed four handfuls or two handfuls, put them on the scale, and found out what their weight was. Then, instead of measuring by volume, we say, "One and a half kilograms, one and a half kilograms" for the livestock. I do not think anyone would say: this contradicts the Sunnah, because the fact that this grain is usually measured by volume does not mean that volume is intended for its own sake. Do you understand? We call them: the feed sellers, or what do you call them? They sell grains. What do you call them?

The questioner: Grain merchants.

The Shaykh: Grain merchants.

The questioner : Yes.

The Shaykh: We call them feed sellers, meaning sellers of feed.
The student: By the scale.

The Shaykh: Ah, yes, these people no longer use volume measurement.

The questioner: Correct.

The Shaykh: They use weight, because it is easier, and it is more precise in terms of the standard, because with volume, you might make a heap that is perfectly high, or one that is slightly lower.