Fries look like the simplest item on a menu. But without a portion standard both the cost and the customer experience fluctuate.
Why do raw and cooked weight differ?
Two things happen at once during frying.
The first is water loss.
Frozen fries carry 60 to 65 percent moisture.
That falls to 40 or 45 percent in frying.
The second is oil absorption.
The product takes up oil equal to 6 to 10 percent of its weight.
The net result is a fall of 15 to 25 percent in weight.
A hundred grams of frozen fries therefore yields around eighty grams cooked; that difference makes it critical which weight the portion definition uses.
What does the yield loss depend on?
Three variables decide.
The first is the thickness of the cut. A thin cut means more surface area.
More water evaporates.
Loss reaches 25 percent at a seven-millimetre cut.
It stays at 15 percent at fourteen millimetres.
The second is the oil temperature. At a low temperature the product stays in longer and loses more water.
The third is frying time; every thirty seconds beyond the standard adds a point or two.
| Cut | Raw portion | Cooked equivalent | Loss | Use |
|---|---|---|---|---|
| 7 mm thin | 150 g | 113 g | 25% | Side |
| 10 mm classic | 150 g | 120 g | 20% | Standard |
| 10 mm classic | 200 g | 160 g | 20% | Large portion |
| 14 mm thick | 180 g | 153 g | 15% | Beside a main |
| Wedges | 200 g | 172 g | 14% | Beside a main |
| Quartered | 180 g | 151 g | 16% | Side |
How is the portion standard set?
The standard emerges from answering three questions.
The first is the role of the product. Side or main?
As a side, 120 to 150 grams raw suffices.
A portion sold on its own runs 180 to 220 grams.
The second is the audience. Portions are larger in a family restaurant, smaller in a café.
The third is the price point. Portion size determines the perceived value of the price.
Those three answers combine into a single figure, and that figure gets fixed in the kitchen.
How do fries balance the plate?
Fries should stay in proportion to the other components.
A hundred and fifty grams raw is balanced beside a two-hundred-gram burger.
A hundred and eighty beside three hundred grams of meat.
A hundred on a breakfast plate.
Too many fries make a plate look cheap.
Too few leave the customer feeling short-changed.
The visual proportion matters too; fries should cover around a third of the plate.
Beyond that the main product falls into the background and the plate gives the impression that the fries are filler.
How is the portion cost calculated?
The calculation works from the raw weight.
The price of a kilogram of frozen fries forms the basis.
A hundred-and-fifty-gram portion is 15 percent of that kilogram price.
The cost of oil joins it.
Oil equal to 8 percent of the product weight gets absorbed; a hundred-and-fifty-gram portion takes up twelve grams.
The oil itself gets changed over time; the cost of changing it gets spread across portions.
Salt, seasoning and packaging are small but non-zero items; with the total worked out, the aim is to keep it between 20 and 30 percent of the selling price.
Why is weighing discipline necessary?
Portioning by eye is the largest leak in cost.
A difference of 20 to 30 percent appears between two members of staff.
Portions grow during busy hours.
They shrink during quiet ones.
That fluctuation produces two consequences.
Cost becomes unpredictable.
And the customer experience turns inconsistent; the same product looks different on two visits.
The solution is simple: a portion scoop or a scale.
How is a portion scoop used?
A scale is not practical every time.
A measure by volume is faster.
A container matching the chosen weight gets selected.
That container gets calibrated once against a scale.
The same container then serves every portion.
The deviation stays under five percent.
In basket fryers the number of portions per basket gets fixed instead.
Two portions go into a basket, which keeps both the weighing and the cooking time standard; an overcrowded basket lowers the oil temperature and the product takes up oil.
How does it get written on a menu?
That is both a legal and a commercial question.
Where a menu states a weight, which weight it means should be stated.
The general practice states the served — that is, cooked — weight.
A hundred and fifty grams of raw potato appears on the menu as 120 g.
Stating the raw weight counts as misleading.
Some businesses state no weight at all; that is a valid choice too.
But once a weight appears, consistency becomes obligatory; a portion measured in an inspection has to match the menu, and that makes weighing discipline necessary in its own right.
How does the loss get reduced?
Four methods work.
The first is the right oil temperature; a hundred and seventy-five degrees minimises both the time and the loss.
The second avoids overfilling the basket; product filling half the basket volume is ideal.
The third fries frozen product without thawing; thawed potato both takes up more oil and loses more water.
The fourth standardises the time; using a timer gains five percent in yield against judging by eye.
Applied together those four bring the loss from 25 percent down to 18; in a business using a hundred kilograms of potatoes a month that means a gain of seven kilograms.
