and , no the following answers don’t count:
because if it’s served in squares it’s called cobbler (but the crust is different)…
because statistics are diagrammed in pie charts.
– because corn bread are square (reference to an old, old joke, based on “pi R squared” math formula)
It’s not always round. Just most commonly so.
I think they’re round because the dishes they’re baked in are too. Which isn’t much of a reason.
“Back in the day” it was much easier to make a round baking dish than a square one.
Additionally, it’s much easier to press or roll the dough for the crust into a round(ish) shape than square. It’s a natural shape for this kind of thing, which probably is why pizzas, hamburger patties, tortillas and pancakes tend to be traditionally round as well, among many other similarly-formed foodstuffs.
I don’t think it’s because the dish is easier to make – I suspect it’s to provide more even baking. It’s much easier to put a lot more heat into the corners (which get heat from two sides) than to the middle of a side (where it mostly comes from one side). No matter how careful I am in making brownies, the corners always seem tio come out drier and more cooked.
In a round pan, all othe things being equal, the baking will be much more even all around. The same goes for all those round cake pans, too.
Yeah, I know that you can bake and cook evenly, even with rectangular pans (look at all those sheet cakes), but it’s easier and more likely to come out more uniform with a round pan/pie dish. That’s why they do it.
Because the circle is a beautiful shape.
What?
My WAG is that when you cut a pie, it’s from center to edge so everyone gets filling and a nice chunk of crust. If say, a cherry pie, was cooked in a square or rectangular pan you’d have some crusty pieces and some goopy blob pieces that are lacking in the yummy crust. I mean, a nice slice of pie sitting next to a scoop of french vanilla ice-cream is just so much more aesthetically pleasing than if it were next to a goop blob of cherry compote. IMHO. 
They aren’t always round. My mother used to bake rectangular and square pies. Likewise the US Army, when I was part of that fine organization, used to have enormous rectangular pies in the mess halls.
In some pies (e.g., chicken pot pie, apple pie) the crust plays a crucial role in connecting the top and bottom crust. A round pie ensures that every slice will have crust.
I think even baking of circular objects is just a serendipitous effect of making them circular in the first place; basic ceramic dishes are pretty much always round; and pastry naturally rolls out into a rough circle. Even pasties (that’s savoury pastry-encased foods baked on a tray, not adhesive nipple adornments) are semicircular largely because circles of pastry (which are then folded over around the filling) are just what you naturally get.
Same thing with hand-made pies - roll out a blob of dough; it forms a circle - dump some filling in the middle and fold up the edges all around it - you end up with a pie that is roughly circular.
More so with pizza; making a non-round pizza crust by traditional hand methods is just too difficult.
Doubtful. I think pies were round long before people knew about heat flow. Q.E.D.'s ‘because it’s the most natural and easiest’ is more likely.
'Cause if it’s not round, it’s cobbler.
Yeah, but you do not have to know the scientific reason for heat flow to know: round shape - seems to cook up better; square shape - not as good.
Yeah…but… making a square pie would just be extra hassle in ancient types; as indeed would making a square pie dish - corners are just something that can easily go wrong when you’re making primitive pottery, so you make round bowls, pots, plates etc - even if you’re not using a wheel.
‘types’=times :smack:
SlyFrog got here before I returned and made my answer.
It’s not obvious to me that round is the “natural” form for pans. If you’re making a metal pan, rectangular is way easier. Even if you’re making pottery forms, you can easily make them rectangular and use up your oven space more efficiently. I grew up with natural pottery-type clay in my backyard. I speak from experience. It isn’t all pottery wheel and coiled pots.
traditional ovens would not necessarily have been rectangular; you’re thinking about this from an engineering/design perspective; pots and pans may not have to be round, but generally, they are - historically even more so; it’s irrelevant whether they could have made square pie dishes, because they simply didn’t. The question is not ‘what’s the best shape for a pie?’; it’s ‘why are pies (traditionally) round?’
Contemporary Pie, in the form that we know it is of course “Pot Pie”.
Sweet and savory pies were made by using the inlay of cooking vessels or pots and of course the traditional shape of a pot is round. In the case of the round pie, it seems the chicken came before the egg, and it may be more accurate to ask why pots are round.
Sure but this implies purposeful experiments. If you take of hand-formed lump of dough and squish it out either with your palms or a roller it comes out sort of round. Why go to the extra trouble of cutting it square?
Actually,I’d take issue even with this; it may be the case now that rectangular is easier, but this will not always have been the case; angular objects made from cast iron (using primitive methods) are generally more prone to casting defects and subsequent breakage than are round ones; even metal vessels made from plate would have been beaten from flat with a mallet and a leather sandbag - round is very much the natural shape for these.
It isn’t all wheels and coils, but they are certainly the most common manufacturing methods, possibly because they’re the quickest and easiest. People have been making pies or things like them since at least when the pyramids were being built and they used round pots to make them in, because that’s what they had.
Further to devilsknew’s quote; pie crusts were also used for short-term preservation of meats; pork pies consisted of ground pork cooked into a sort of meatloaf, completely encased in dense, salty pastry; the meat would remain edible for a while this way, if kept in a cool place - then the pastry would be cut off and discarded and just the meat filling would be eaten.