Coffee Roast Yield Loss Calculator

Roast preset:

Start from a light, medium, dark, or production batch profile.

Weight unit:

Use the same unit that appears in your roast log.

Green coffee in:

Enter the batch charge weight before roasting.

Roasted coffee out:

Enter the post-roast output weight after cooling.

Target roast loss: {{ targetLossDisplay }}

Typical specialty roast loss often lands around 12-20%, with darker roasts higher.

QC/sample pull:

Subtracts from roasted output to show sellable roasted coffee.

Currency:

Used for cost and JSON output labels.

Green landed cost:

Cost per selected weight unit before roast loss.

{{ currency }}/{{ weight_unit }}

Batch overhead:

Added to green spend before cost-per-roasted-unit math.

{{ currency }}/batch

Roasted output target:

Useful for planning orders or bag counts before roasting.

Batch count:

Leave at 1 for a single measured roast.

Retail package size:

Enter a common bag size, such as 340 g, 12 oz, 1 lb, or 1 kg.

Green moisture estimate: {{ moistureDisplay }}

A simple estimate for interpreting loss, not a replacement for a moisture meter.

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Cost item	Value	Use	Copy
{{ row.item }}	{{ row.value }}	{{ row.use }}

Plan item	Result	Action	Copy
{{ row.item }}	{{ row.result }}	{{ row.action }}

{{ jsonOutput }}

Enter positive green and roasted weights to calculate roast yield loss.

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Coffee loses mass every time it is roasted. Green beans enter the roaster with water, organic compounds, chaff, and trapped gases. Heat removes some of that material while the bean expands, darkens, and changes chemically. The difference between the green charge and the cooled roasted output is roast loss, usually expressed as a percentage of the green weight.

Roast loss is useful because it connects cup development with production math. A lighter filter profile may finish near the lower end of a roaster's normal range, while a darker espresso profile often loses more mass. Green moisture, batch size, airflow, charge weight, development time, endpoint, cooling, scale tare, and the exact moment of weighing can all move the number. Comparing batches only works when the same measurement points are used each time.

The percentage should not be treated as a quality grade. Two coffees can share a roast-loss value and taste different because density, moisture history, variety, process, heat application, and sensory targets differ. The value is better used as a consistency clue: if the same coffee and profile suddenly shift by several points, the roaster should check moisture, roast endpoint, scale workflow, and batch notes before assuming the profile was repeated.

Roast loss planning terms
Term	What it counts	Why it matters
Green weight	The charge weight before roasting.	It is the denominator for roast loss and cost planning.
Roasted weight	The cooled output before QC or sample pulls.	It shows the actual roast yield from the batch.
QC pull	Coffee removed after roasting for cupping, color checks, purges, or samples.	It reduces sellable coffee but does not change roast loss.
Target loss	The expected loss percentage for a profile or production plan.	It turns a batch result into a drift check.

Production planning adds a business layer to the same mass balance. A batch can hit its roast-loss target and still fail an order if cupping pulls, grinder purges, retail package size, or target-output planning are ignored. Cost per roasted unit and cost per sellable unit should therefore be kept separate.

How to Use This Tool:

Start with the core batch weights, then add cost and packing assumptions only after the green and roasted values are correct.

Choose a Roast preset or enter a custom batch. Presets load realistic values for medium production, light filter, dark espresso, and sample-roast scenarios.
Set Weight unit, then enter Green coffee in and Roasted coffee out from the same cooled batch. Roasted output must be positive and cannot exceed green input.
Enter Target roast loss to compare the measured batch against the profile expectation. The target is bounded from 5% to 35% for calculation.
Add QC/sample pull when coffee is removed before selling or packing. This affects sellable weight, cost per sellable unit, and package count.
Fill Green landed cost, Batch overhead, and Roasted output target when you need production cost or a green-weight back calculation.
Open Advanced for Batch count, Retail package size, and Green moisture estimate. Batch count is rounded to a whole number, package count is floored to full packages, and moisture is used as a review estimate.
Read Yield Ledger first, then use Cost Ledger, Production Plan, Loss Sensitivity Chart, and JSON when you need planning or export detail.

Interpreting Results:

Roast loss percent is the headline consistency signal. Roasted yield percent is the output side of the same relationship, so the two add to 100% before QC pulls. Sellable roasted coffee subtracts QC or sample coffee after roasted output is multiplied by batch count.

Target drift compares actual loss with the entered target. A drift within 0.5 percentage points is labeled on target. Drift above 0.5 and up to 1.5 points is a watch item. Larger drift asks for review. The label is not a defect call; it tells you whether the batch matched the plan closely enough for the next production decision.

Roast yield result fields and interpretation
Result	How to read it	What to check next
Roast-loss signal	Places the measured loss in a broad light, medium, darker, or review range.	Compare only with similar coffees and measurement workflow.
Cost per roasted unit	Spreads green spend and overhead over all roasted output.	Use for internal batch costing before removals.
Cost per sellable unit	Spreads the same cost over roasted coffee left after QC pull.	Use for pricing and order planning when samples or purges reduce stock.
Full retail packages	Floors sellable weight into complete package fills.	Plan the remainder as bulk, samples, staff coffee, or blend stock.

If the result does not fit the roast log, recheck the unit selector, tare, batch identity, cooled weighing point, and whether QC coffee was removed before or after the roasted weight was recorded. Those workflow mistakes can look like profile changes.

Technical Details:

Roast yield loss is a direct mass balance. The green charge is the starting mass, the cooled roasted output is the remaining mass, and the lost mass is assigned to water, carbon dioxide, volatile compounds, chaff, and other material driven off during roasting. QC pulls are deliberately kept outside the roast-loss equation because they happen after the roast output is known.

Mixed units are converted to a single kilogram basis before the calculation. Display values are returned in the selected weight unit, while package size can use its own unit. Cost per sellable unit is more conservative than cost per roasted unit because it divides the same total batch cost by less coffee after QC or sample removal.

Formula Core:

Let W_green be green coffee in, W_roasted be cooled roasted coffee out, W_QC be the QC/sample pull per batch, N be batch count, and L_target be the target roast loss percentage.

\begin{array}{lcl} L_{pct} & = & \frac{W_{green} - W_{roasted}}{W_{green}} \times 100 \\ Y_{pct} & = & 100 - L_{pct} \\ W_{sellable} & = & (W_{roasted} \times N) - (W_{QC} \times N) \\ W_{green needed} & = & \frac{W_{target roasted}}{1 - \frac{L_{target}}{100}} \end{array}

A 12 kg green batch that cools to 10.2 kg loses 1.8 kg. Dividing 1.8 kg by 12 kg returns 15.0% roast loss and 85.0% roasted yield. With one 0.2 kg QC pull, sellable output is 10.0 kg. If green coffee costs 9.40 per kg and overhead is 18.00, total batch cost is 130.80 and cost per sellable kilogram is 13.08 before packaging, labor margin, waste, or tax.

Coffee roast loss bands
Measured loss	Signal	Review cue
Below 10%	Very low loss	Check tare, cooling state, unusually light development, or green moisture.
10% to below 13%	Light range	Often consistent with lighter roast development.
13% to 17%	Medium range	A common production range for many specialty profiles.
Above 17% through 22%	Darker range	Fits darker or longer development profiles.
Above 22%	High loss review	Check roast degree, moisture, scorching risk, or measurement error.

The green moisture estimate is a comparison aid, not a full moisture model. The calculation reports loss beyond the estimate by subtracting the entered moisture percentage from measured roast loss and flooring the result at zero. Target loss is clamped from 5% to 35%, green moisture from 6% to 16%, QC pull cannot remove more than the batch roasted output, and package count uses whole filled packages only.

Coffee roast yield validation rules
Rule	Boundary	Reason
Green and roasted weights	Both must be positive, and roasted output cannot exceed green input	Roasting cannot create more mass than the starting charge.
Target drift state	Within 0.5 points is on target; within 1.5 points is watch drift; larger is review drift	Small differences are normal, while larger shifts should be checked against the profile and scale workflow.
Batch count	Rounded to at least 1 batch	Production totals use whole repeated batches.
Retail packages	Floored to full packages	Partial remainder is tracked separately instead of counted as a sellable package.

Worked Examples:

Medium production batch

A 12 kg charge roasted to 10.2 kg returns 15.0% roast loss and 85.0% roasted yield. With a 15.0% target, measured drift is on target, so sensory notes, color, and repeatability become the next checks.

Dark espresso profile

A 15 kg green batch roasted to 12.15 kg has 19.0% loss, placing it in the darker range. If 0.25 kg is pulled for checks and package size is 1 lb, package count uses only the sellable weight after that pull.

Target-output back calculation

Planning 10 kg roasted output at a 15.0% target loss needs about 11.76 kg green coffee. If current batches are drifting higher than target, the same green draw will come up short.

Invalid weight entry

If roasted output is entered above green input, the result is blocked because the mass balance is impossible. Recheck the selected unit, tare, batch label, and cooled output weight before using the ledgers.

FAQ:

Is roast loss the same as roast quality?

No. Roast loss is a weight-based consistency and planning signal. Cup quality still depends on sensory review, color, development, green condition, and the intended profile.

Should QC samples be part of roast loss?

No. Roast loss uses green input and cooled roasted output before QC or sample coffee is removed. Enter QC pulls separately so sellable output and cost allocation are accurate.

Why is cost per sellable unit higher than cost per roasted unit?

The same green spend and overhead are divided over less coffee after QC or sample removal. Removing more non-sellable coffee raises cost per sellable unit.

What does loss beyond green moisture estimate mean?

It is measured roast loss minus the entered green moisture estimate, floored at zero. It is a rough review clue for development, chaff, gases, and other non-moisture loss, not a laboratory moisture test.

Glossary:

Roast loss: The mass lost between green coffee in and cooled roasted coffee out, expressed as a percentage of green weight.
Roasted yield: The cooled roasted output as a percentage of green input before QC pulls.
QC/sample pull: Roasted coffee removed for cupping, color checks, grinder purges, training, or internal samples.
Sellable roasted coffee: Roasted output left after QC or sample removal.
Target loss: The expected roast loss percentage for a profile, lot, or production plan.
Target green needed: The green charge estimated to produce a requested roasted output at the selected target loss.

References:

Coffee Roast Loss: What's Normal and What to Track, Green Coffee Collective.
Understanding Roast Yield and Loss, Royal Coffee.
Coffee roasting: how and why it causes coffee to lose weight, MTPak Coffee.