Chapter 11 — Teaching Notes

What this chapter is doing

Chapter 1 asserted that prime cost is the number that predicts survival, and that most operators cannot compute half of it. Chapter 11 is where that accusation gets discharged. It has three jobs and they should be taught as three jobs, not one:

  1. Correct the measurement. Food cost is what you used, not what you bought. The two-period example in §11.1 is the chapter's argument, and it is the single most important twenty minutes of the course after Chapter 1's prime-cost section.
  2. Build the instrument. The Hearth Chicken cost card, derived line by line from batch recipes, measured yields, and portion specs.
  3. Show its limits. A cost card excludes labor and fuel; a percentage is blind to mix; a target price is a smoke detector, not a thermostat; a variance says how much, never what.

If students leave able to compute a food cost percentage but still believing the number is trustworthy, the chapter has failed. The point is a disciplined distrust of a number they will use every week for the rest of their careers.

Timing

  • A 75-minute session: §11.1 with Figure 11.1 worked live (25 min) → §11.2's card built on the board, line by line (25 min) → §11.7 ideal vs. actual with Figure 11.5 (20 min) → assign the rest. This is the minimum viable version and it works.
  • Two sessions: split after §11.4. Session one is measurement and the card (§11.1–11.4); session two is pricing, portioning, variance, and re-costing (§11.5–11.8). The second session is more fun and the first is more important; do not let the split invert that.
  • Three sessions: add a hands-on yield test (see below). Worth it if you have any access to a kitchen.
  • Self-paced: 5–7 hours including exercises. Tell students the exercises are the chapter.

Common misconceptions

1. "Food cost is invoices divided by sales." Chapter 1 previewed this; Chapter 11 has to kill it. Students who have worked in restaurants are the most resistant, because it is what they watched their manager do. Do not argue — put Figure 11.1 on the board with the true-food-cost row blank, have them compute invoices ÷ sales for both periods, ask which period was better, let the room commit, and then fill in the true row. The reversal does the teaching. Follow immediately with the identity (shortcut − true = ΔInventory ÷ sales), which converts a surprise into a rule.

2. "Dividing by yield makes cost go down." Reliably wrong on the first attempt, in every cohort. The fix is physical, not verbal: hold up a whole carrot and a peeled one. You paid for the first and can only sell the second, so the price of the first has to be recovered across the weight of the second. Then have them do it both ways (AP ÷ yield, and case cost ÷ usable weight) and notice the answers agree.

3. "A lower food cost percentage is better." The most stubborn one, because it is nearly true. Use §11.1's mix demonstration: moving twenty covers from the pork chop to the grain bowl improves food cost 0.6 points and costs the restaurant \$137.20 that week. Ask what they would do if a consultant promised to cut their food cost by a point. Then reveal that deleting the ribeye would do it.

4. "The cost card tells you whether the dish is profitable." It does not — it prices ingredients. The shadow card in §11.2 (\$8.52 of product, \$9.94 consumed, 34.3% of price) is the correction. Anticipate the natural follow-up — then why not put labor on the card? — and have the answer ready: because then your number is comparable to nothing, and because labor belongs to the other half of prime cost, where you can actually manage it against a schedule.

5. "Portion drift means somebody is being careless." Students moralize this immediately. §11.6's five mechanisms exist to stop them. Push hard on the fifth: over-portioning is very often an act of generosity by a good cook, and a manager who treats it as a discipline problem loses the cook and keeps the problem.

6. "A big variance means theft." Universal, and the same bias Chapter 1's instructor notes flagged about the 34.5% food cost. Work the investigation order in §11.7 and make them notice that theft is seventh. Then ask what it costs to investigate theft first and be wrong.

The hardest point to teach

That the correct response to a cost increase is to restore the dollars, not the percentage.

Students can follow §11.8's arithmetic — an 85-cent cost increase, a \$30 price to restore contribution margin, a \$32 price to restore the ratio — and still not feel why the \$32 answer is wrong, because \$32 produces the "right" food cost percentage and \$30 does not. Their whole training to that point has been that the percentage is the target.

What works: put both prices on the board with their contribution margins (\$20.63 and \$22.63) and ask the class to justify the \$32 price to a guest. Someone will eventually say out loud that you are charging them \$3 more because your ratio moved, and the room hears it. Then run Exercise 11.26, where the effect is starker — a 95-cent cost increase requiring a \$3.58 price move and handing the operator \$2.63 a plate more contribution than they started with.

The sentence to leave them with: a percentage is a description of your business, not an obligation your guests owe you.

A demonstration that works

Build the Hearth Chicken card live, on the board, with the components hidden.

Give the class only: half a 3.5 lb air-chilled bird at \$3.20/lb, roasted roots, salsa verde, butter and aromatics, oil and seasoning, garnish. Ask them to guess the plate cost before any arithmetic. Write the guesses down — they will cluster between \$4 and \$6, because everyone anchors on the chicken and forgets the rest.

Then build it: \$5.60, and the class thinks they are nearly done. Add the roots batch (12 lb AP → 9.0 lb trimmed → 7.6 lb roasted; \$0.19/oz; \$0.95). Add the salsa batch (\$28.00 ÷ 40 fl oz = \$0.70; \$1.05). Add the three small lines. Land on \$8.35, add 2%, land on \$8.52.

The teaching moment is that the four non-protein lines add \$2.75 — nearly half again the chicken — and every guess in the room missed them.

Extension, if you have twenty more minutes: now add the \$0.79 of butchery labor and \$0.63 of hearth fuel and watch a 29.4% item become a 34.3% one. Ask which number they would put in a business plan, and which they would manage by. The answer — the first in the plan, the second in your head — is the chapter.

If you have access to a kitchen: run an actual yield test. A case of carrots, a scale, a peeler, and one volunteer produces a real yield percentage in fifteen minutes, and it will not match the number the class expected. Have a second volunteer do the same case and compare — the spread between two people is the lesson of §11.4, and no lecture delivers it.

Assessment notes

  • Exercises 11.8, 11.16, 11.22, 11.27, and 11.28 are the computational core. A student who can do those five can cost a menu, run a butcher test, price against a target, compute true food cost from a count, and produce a variance. That is the chapter's entire skill set.
  • 11.27 is the single best diagnostic in the chapter and should be on every exam. Part (d) — the identity check — separates students who followed the procedure from students who understood it.
  • 11.21 and 11.32 are the prime-cost trades and reward students who notice that a labor "saving" is only a saving if somebody actually goes home. Watch for students who assume the hours vanish.
  • 11.32 contains a deliberate double-counting trap. Roughly half of any cohort will add the Q-factor reduction to the ingredient saving. Do not warn them; it is the most memorable error in the set, and it generalizes to every in-house-production business case they will ever be handed.
  • 11.24 is the best judgment item. Look for students who notice that the formula is closest to right on the mid-priced item and systematically wrong at both ends.
  • 11.33 (the ethics problem) is the best written assignment. The tell of a strong answer is that it separates the two changes: the portion reduction is a judgment call with a defensible version; the unchanged "air-chilled" menu copy is not. Students who treat both as matters of degree have missed it. Students who treat both as absolutes have over-corrected.
  • 11.34 (the memo) reveals more about a student's management instincts than anything else in the chapter. Mark down any memo whose theory is that people are cheating, and any memo that asks the team to "be careful."

Connections forward

Flag these explicitly so students build the map: cost cards → Chapter 12 (contribution margin and the four quadrants — say plainly that Chapter 11 built the inputs and Chapter 12 makes the decisions). The count → Chapter 13 (Chapter 11 owns the arithmetic; Chapter 13 owns the clipboard). Portion discipline under pressure → Chapter 14. The labor half of every trade in this chapter → Chapter 19. Variance as a theft control → Chapter 34. Food cost's place on the statement → Chapter 31. The whole method in liquid form → Chapter 15.