Why does a baker's dozen contain 13 items?

Answer 1

Origin
The oldest known source and most probable origin for the expression "bakers dozen" dates to the 13th century in one of the earliest English statutes, instituted during the reign of Henry III (r. 1216-1272), called the Assize of Bread and Ale. Bakers who were found to have short-changed customers could be liable to severe punishment. To guard against the crude punishment of losing a hand to an axe, a baker would give 13 for the price of 12, to be certain of not being known as a cheat. Specifically, the practice of baking 13 items for an intended dozen was to prevent "short measure", on the basis that one of the 13 could be lost, eaten, burnt or ruined in some way, leaving the baker with the original dozen. The practice could be seen in the guild codes of the Worshipful Company of Bakers in London.


Modern uses
While modern bakers no longer fear medieval law, they have found other reasons for a baker's dozen, as seen in the tidy way 13 disks (cookies, biscuits, etc) can pack a rectangle (baking tray) of appropriate proportions. Modern standard sized packing trays have a 3:2 aspect ratio, and the most efficient two dimensional array is hexagonal close packing which has sixfold symmetry such that each baked item is equidistant from its six nearest neighbors. The corners of a cookie sheet heat up and cool off faster than the edges and interior, so any item placed near a corner will not bake at the same rate as the other items. A 4+5+4 arrangement provides the dense hexagonal packing while avoiding corners, and would have been discovered empirically by bakers with the goal of baking the maximum number per batch with optimal uniformity. Continued use also stems from tradition, and some customers see it as a sign of appreciation from the baker for continued patronage.

Answer 2

It originally started out (many years ago) because bakers could be put in jail if you paid for a dozen items and did not get a full dozen, so to be safe the baker would give you and extra item.

Answer 3

In the middle ages there were harsh punishments for bakers if, for example, their loaves were too small. Adding an extra to the dozen was a safeguard against a) one of the items being spoiled or stale, and b) getting (for example) dunked in the river once a day for an hour, even when it meant having to chop through the ice to do it.

Answer 4

Sometimes baker's would have a little extra dough - so the extra dough became another item and they would include it with the dozen - it's also a good marketing trick!

Answer 5

a dozen and one for the baker? lol
looks like they never wanted to short change anyone

Answer 6

it used to be a practise amongst bakers, if you ordered a full dozen, they would give you one extra as a bonus.

Answer 7

So you could eat one on the way home, and still have a dozen to present when you get to your destination. He he!

Answer 8

It used to be practise that if you ordered a dozen they ate the extra one.

Answer 9

13 try 14 like Safeway's doing to make a profit! There a lot of fat people that like to get in on these donut bouying deals.