How much you will actually get

A kilogram of whole spice does not become a kilogram of jarred product, and the gap is larger and less predictable than people budget for.

Where the weight goes

Four places, and only one of them is obvious. Cleaning removes stems, chaff, stones and oversize. Grinding leaves material in the mill, and some escapes as airborne dust. Sifting removes the fines and the oversize you chose to exclude. Filling leaves residue in funnels and scales and on the bench.

Moisture also leaves during grinding, which is a real weight loss and not only a quality one.

Whole to ground

The yield depends heavily on the spice and on how much cleaning it needs. Clean whole peppercorns lose very little. Dried chilies with stems on lose a great deal. Herbs with stem material can lose a third before anything is ground.

Rather than trusting a general figure, weigh it once for each line. Weigh in, weigh the cleaned material, weigh the ground and sifted output, and write the three numbers on the product record. That is your yield and it is stable enough to plan with.

Cleaning loss

This is the one that varies most between suppliers, and it is a hidden price difference. A cheaper lot that needs more cleaning can deliver less usable product per pound than a dearer one.

Which means yield is a supplier comparison tool. Two lots at different prices should be compared on cost per kilogram of finished jarred product, not on invoice price.

Working out jars per kilogram

Take the net weight you declare, divide the usable yield by it, and subtract a little for the last partial jar and for check-weight overfill.

Remember that you fill slightly above the declared weight deliberately, because the distribution has two tails and only the low one is a compliance problem. On a small jar that overfill is a meaningful share of the total, so build it into the calculation rather than discovering it as a shortfall.

References