FREE CALCULATORS › ROAST LOSS CALCULATOR
Coffee roast loss calculator
How much weight did your roast lose, what does a kg of roasted coffee really cost you - and how much green coffee do you need for an order? Type in your weights, the result is there at once.
How the roast loss is calculated
roast loss % = (green weight - roasted weight) / green weight × 100 cost of 1 kg roasted = green price per kg × green weight / roasted weight + roasting costs per kg green needed = roasted coffee needed / (1 - roast loss)
Example: 12.0 kg green in, 10.15 kg roasted out: (12.0 - 10.15) / 12.0 = 15.4 % roast loss. At 8.00 EUR per kg green, a kg of roasted coffee holds 8.00 × 12.0 / 10.15 = 9.46 EUR of green coffee, plus 1.50 EUR roasting costs = 10.96 EUR per kg. For 60 kg roasted at 16 % loss you need 60 / 0.84 = 71.4 kg green.
The roast loss is mostly water and some organic matter. Most roasts lose 12-20 %: light roasts less, dark roasts more. Weigh the beans after cooling, always the same way - and track the loss per batch: a batch far from your mean is worth a cupping.
On the scale it is done while you weigh
The ROASTERY ☕ MODE of UP↑SCALE books green in, roast in and roast out on the scale - and shows the roast loss of every batch before you book it. The roast log keeps the loss, the colour and the cost per kg of every batch, the planner works out the green coffee from your last 10 batches, and fill weighing puts the batch into bags with live statistics. On the scale you already have.
More for Coffee roasters · open the free app · does my scale work?
Roast loss: questions and answers
What is a normal roast loss for coffee?
Usually 12-20 % of the green weight: about 12-14 % for light roasts, 15-17 % for medium and up to about 20 % for dark roasts. Your own mean depends on the beans, their moisture and your roaster - track it per batch.
How do I calculate roast loss in percent?
Roast loss % = (green weight - roasted weight) / green weight × 100. Example: 12.0 kg green and 10.15 kg roasted give (12.0 - 10.15) / 12.0 × 100 = 15.4 %.
How much green coffee do I need for 1 kg of roasted coffee?
1 kg divided by (1 - roast loss). At 15 % loss that is 1 / 0.85 = 1.18 kg green, at 18 % loss 1.22 kg.
How do I calculate the cost of a kg of roasted coffee?
Green price per kg × green weight / roasted weight, plus your roasting costs per kg. At 8.00 EUR per kg green and 15.4 % loss that is 9.46 EUR of green coffee in every roasted kg; with 1.50 EUR roasting costs 10.96 EUR.
Why does the roast loss change from batch to batch?
The moisture of the green coffee, the batch size, the charge temperature and the end of the roast all move it. A batch far from your mean usually tastes different too - worth a cupping before it goes into bags.
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