Why are 13 items called a Baker's Dozen? Why can't there be a Brewer's Dozen?

Question

Why are 13 items called a Baker's Dozen? Why can't there be a Brewer's Dozen?

Answer 1

The origin of the phrase "a baker's dozen" comes from times when baker's packages would be weighed to make sure that they were not stiffing their customers. Instead of risking a big fine for coming in too light, the baker would put an extra roll or loaf or pastry into the box, to make sure they qualify.