The invoice comes in and the chicken is up eleven percent. The menu says what it said last March. Between those two facts is the reason a busy month can end flat.

Know which dishes care

A price rise on one ingredient is not a menu-wide problem. It is a problem for the four dishes that ingredient carries. Before you touch anything, work out which dishes those are and how much of each plate the ingredient actually is.

Half the time the answer is that it does not matter — a rise on an ingredient that is a small part of a plate barely moves the cost. The other half it is the whole dish, and that is where you spend the afternoon.

The moves you have, in order

• Wait. Some things spike and come back. Know which of your ingredients do that before you reprice.
• Change the plate. A different garnish, a different cut, one ounce less of the expensive part.
• Move the price. Smallest step that gets the dish back where it was.
• Take it off. A dish that only worked at the old cost was never a good dish.

Do it in odd amounts, not round ones

Every item going up a dollar on the same day is the version guests notice. Three dishes moving fifty cents, one moving a dollar fifty, on a week when a new special appears, is the version nobody mentions.

The reason menus lag

Printed menus set the pace. Reprinting costs money and a day, so the price change waits for the next print run, and the next print run waits until enough changes have piled up. The gap is not a decision anybody made. It is just what printing does.

When the menu lives on a screen, the price change takes the time it takes to type it. You change it after the invoice lands, publish, and the next table to scan sees the new number. Nothing to reprint, nothing to throw away, no stack of old menus in the office.

Watch it for a fortnight

A price move is a guess until you see what it did. Watch how often the dish sells for the two weeks after. If the count holds, you were charging too little before. If it falls off a cliff, you have learned something worth more than the fifty cents.

Costs move every week. A menu that can only move once a year is what turns a good month into a flat one.