How to Calculate Coffee Roast Loss
Roast loss is the difference between green coffee weight and finished roasted weight, expressed as a percentage of the green weight. Measuring it helps you plan production and understand coffee cost.
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Use the roast loss formula
Roast loss (%) = (green weight - roasted weight) / green weight × 100. Use the same unit for both weights and a green weight greater than zero. Weigh the coffee without the container, and measure finished coffee at a consistent point after cooling.
Work through a batch example
A batch starts with 10 pounds of green coffee and finishes with 8.5 pounds of roasted coffee. The difference is 1.5 pounds. Dividing 1.5 by 10 and multiplying by 100 gives a 15% roast loss. Yield is 85%, calculated as 8.5 divided by 10.
Translate yield into the next production plan
To make 20 pounds of roasted coffee at that illustrative yield, divide 20 by 0.85: you need approximately 23.53 pounds of green coffee. Actual yield varies, so use your own records rather than treating the example as a target.
Keep roasting and packaging losses separate
Coffee removed for samples or lost during packing reduces saleable output, but it is not all roast loss. Recording those steps consistently helps you identify where a difference occurred. In RoastBase, enter green and finished roast weights to calculate batch yield and roast loss.