Trim waste percentage

What it is and why it matters

Many raw materials can't be used exactly as they are bought: they need cleaning, and cleaning removes parts that never reach the plate (peels, seeds, bones, fat, sinew, fish bones, offal). That intentional loss during mise en place is trim waste.

Knowing the trim waste % of each raw material lets you work out how much to buy and how much money you'll need, cost recipes, compare buying untrimmed vs. trimmed, check the supplier at receiving and check how cleaning is done in the kitchen.

The formula

• Trim = gross weight − net weight
• Trim waste % = trim ÷ gross weight × 100

What each value means

Gross weight (as purchased)

What the product weighs as you buy it, with all its trim.

Net weight (clean)

What is left after cleaning: the quantity ready for the recipe.

Trim

The difference between both weights: what is removed when cleaning.

Step by step

1. Weigh the product as purchased, before cleaning it.
2. Clean it, setting the trim aside.
3. Weigh the clean product.
4. Subtract: gross weight − net weight = trim weight.
5. Divide the trim by the gross weight and multiply by 100.

Worked examples

Study notes

• Rounding

  If the math gives decimals (say 27.4%), rounding up is the safe choice: you buy a little extra. Just keep in mind it is a rounding, not the exact value.

• Tip

  Trim waste isn't fixed for a given raw material: it changes with origin, size and the judgment of whoever cleans it, and above all with the recipe it's for. An apple for tarte Tatin isn't trimmed like one for jam.

• Tip

  Conservative approach: count the trim as lost. Business approach: reuse it in other dishes on the menu, adding as much value as possible.

• Common mistake

  Don't confuse trim waste (removed when cleaning) with cooking loss (lost when cooking), waste from bad practice or spoilage (thrown away because it went bad).