As-Purchased vs Edible Portion Cost: Costing With Trim and Yield

A chef orders a whole side of salmon at $18.00 a kilo and costs a 180 g portion at $3.24. Then the food cost percentage on that dish keeps coming in higher than the recipe says it should. The reason is almost always the same: the recipe was costed at the price paid, not the cost of the part that is actually served.

All figures here are illustrative examples.

The two costs

• As-purchased (AP) cost is the invoice price per unit: $18.00 per kilo of whole side.
• Edible portion (EP) cost is the cost per unit of what remains after skin, pin bones, belly trim and cooking loss.

The formula is simple:

EP cost = AP cost divided by yield percentage

A worked example

Whole salmon side at $18.00 per kilo. After skinning, pin-boning and trimming, 78% of the weight is usable.

Sell 40 portions a week and the hidden difference is about $36 a week, roughly $1,900 a year, on one dish. Multiply that across a menu and recipe costs that look fine on paper will quietly mislead you.

Two kinds of yield

Keep these separate, because they happen at different steps.

1. Trim yield is what is left after preparation (peeling, boning, trimming).
2. Cooking yield is what is left after cooking (moisture and fat loss).

They combine by multiplication. A roast that is 90% after trimming and 75% after cooking has a combined yield of 67.5%. Cost it per cooked, portioned weight if you serve by cooked weight.

How to run a yield test

1. Weigh the product as purchased.
2. Prepare it exactly as your kitchen normally does.
3. Weigh the usable product. Weigh the trim and by-products too.
4. Divide usable weight by AP weight to get the yield percentage.
5. Repeat at least three times and average the results, because one test can be unrepresentative.
6. Record the result with the date, supplier and who did the prep.

Focus on the items that cost the most or have the most waste first: proteins, whole fish, specialty produce.

What about trim you use?

If you turn trim into stock, a staff meal or a by-product dish, the usable by-product has value. You can give it a small credit, but be conservative. Costing a dish as if every scrap sells is just another way to understate real cost.

Common mistakes

• Costing at invoice price. The most common cause of underestimated plate cost.
• Using one yield for everything. A butcher trims differently than a new cook.
• Testing once. Averages beat a single run.
• Forgetting cooking loss. If you portion cooked, cost cooked.
• Never retesting. A supplier change can move yield by several points.

Where software can help

Check that whatever you use for costing lets you cost by usable weight, or adjust the ingredient price to its EP cost before entering it. ChefMind AI's recipe costing works from the ingredient prices in your inventory, and you can try the free food cost calculator with your own EP numbers. See also how to cost a sub-recipe.

The short version

• Cost what you serve, not what you bought.
• EP cost = AP cost divided by yield.
• Test your own yields, average several runs, and retest when anything changes.