chicago style deep dish pizza

Science of Chicago Deep Dish Pizza

If you’ve never been to Chicago, chances are small you have come across Chicago-style deep dish pizza. It’s a pretty regional phenomenon and personally I haven’t seen it outside of the city, whereas in Chicago every tourist seems to ‘need’ to eat it!

Chicago deep dish is very different from ‘traditional’ Italian pizza. Most of us will think of pizza being flat, with a bread like bottom, a layer of (often tomato) sauce, with a whole range of possible other toppings (vegetables, meats), often including cheese. The Chicago style deep dish though, is not flat, and does have sauce, but a lot more of it and a lot of stringy cheese within! Some might say it is a quiche, not a pizza, it having crust on both the bottom and sides. Others would vehemently protest that, of course.

Fact is, deep dish pizzas need this crust on the sides to keep everything together and it is just one of the things that makes it unique. Another typical Chicago thing is the use of sausage meat on the pizza. All of this is fascinating and there’s even a bunch of science involved to make this pizza.

Choosing a pan for Chicago style deep dish pizza

It all starts with the tray that you bake it in. As opposed to an Italian pizza, you don’t bake this pizza on a flat surface. Instead, you have to bake it in a tin, a bit like a round cake tin. This will keep in all your fillings and hold up the crust. The type of pan you choose will impact your final pizza result.

First of all, for it being a ‘true’ Chicago deep dish, the pan will need to be round. Square or rectangular pans still make delicious pizzas, but it’s not the way it’s traditionally done. (If you’re wondering how old that tradition is, Chicago deep dish originated in the 1940’s.)

A deep dish pizza needs to be baked for quite some time, a lot longer than most ‘flat’ pizzas. A bake of 30-45 minutes is normal and a good pizza pan will help make a good pizza. We’ve made deep dish pizzas though with regular cake tins, which came out good. If you are studying deep dish pans, here are a few pointers:

  • Material: most of the pans are made of steel. Steel is a good conductor of heat and heats up quickly. This helps quicken the process (as opposed to glass or ceramic for instance).
  • Colour: darker pans absorb more heat and thus cook the pizza faster. Since the pan will especially heat the crust, a darker pan may burn the outside of the pizza more easily than a lighter one. That said, adjusting oven times & temperatures will help you over come burning of the outside (lower the temperature, increasing baking time).
  • Thickness: a thicker pan will be more sturdy and generally be somewhat more evenly heated. Too thick a pan though might cause it to hold on to the heat for too long after baking (cast iron for example stays hot for a long time afterwards) and takes longer to heat up. Often the thickness is given in ‘gauges’. The higher the gauge number, the thinner the pan.
pizza city usa chicago style deep dish

What a Chicago deep dish consists of

Once you’ve got your tin, it’s time to build your pizza within. A typical Chicago deep dish pizza consists of at least three components:

  • Crust, which covers the bottom and the sides of the pan. The crust will not cover the top, that would make it more of a pie! Important aspect of the crust is that it’s crispy and crunchy, not soggy. Some makers use a butter crust, or a more bread like crust.
  • Cheese, and quite a bit of it as well. The majority of this cheese sits on the bottom, right on top of the crust, under the tomato sauce. More on that and the cheese in general later.
  • Sauce, most commonly a tomato sauce. Within the sauce possibilities are endless.

Let’s have a closer look.

Crunchy crust – Balancing moisture & crispiness

A Chicago deep dish pizza needs to have a crispy crust. This is harder than it may sound though, since it is full of (a lot of) very moist tomato sauce. Moisture has a tendency to want to even itself out which results in the moisture from the tomato sauce seeping into the crust, making it soggy. Soggy pizza crusts are a no no though.

This moisture migration problem also happens to be one of the major challenges of manufacturers of food products in general. How to maintain that crunchy bread crust or apple pie crust is challenging and for every food slightly different solutions can be used to prevent it (partially). which we discussed before.

Within Chicago deep dish though, there are a few tricks that you use, possibly without even realizing that attempt to overcome this problem.

Cheese as a moisture barrier

First of all, your cheese. You place the cheese on the bottom of a deep dish pizza. Cheese contains quite some fat and it so happens that fat is a great barrier for moisture. It prevents the moisture from the sauce from migrating down into the crust that needs to turn crispy. Placing the cheese on the bottom greatly helps in getting a crispy crust.

Fat in the crust

Most ‘regular’ pizzas use bread dough which consists of mostly flour and water with yeast and salt. They might contain some olive oil, but not too much. A majority of the Chicago deep dish pizza doughs though contain a decent amount of fat. Some even use butter crusts instead of bread doughs, thus containing a lot more fat.

Fat helps a lot in creating a good crust structure. The fat actually helps to crisp up the dough. Again, part of the reason is that it prevents the migration of moisture through it.

deep dish pizza from my pi pizza
My pi pizza, notice the layer of cheese at the bottom?

Deep dish is no deep dish without cheese

Deep dish pizza needs cheese and in most cases, there’s lot (too much?) of it. It helps to keep that crust nice and crunchy, as we mentioned before, but the cheese is also there to balance the whole pizza out. The mild flavour of the cheese, with its creaminess, works well with the rich moist tomato sauce.

Wisconsin mozzarella cheese

If you pick up a piece of deep dish from the pan you should get a long strand of cheese coming off. This long, stringy cheese is all too familiar on lots of Chicago deep dish photos. Not every cheese can form this stringiness though, most cheeses will break too soon to form these long strands. This is why most Chicago deep dish pizzas contain mozzarella cheese, more often than not from Wisconsin (the dairy state of the USA, which lies just north of Chicago). Mozzarella cheese gets its stringiness from its production process, in which the cheese is literally pulled into these strands.

Within the mozzarella cheese realm there are two types of mozzarella: the fresh moist one or the drier version. On a deep dish you’d want to use the drier version and not the very moist version. The high amount of moisture would still make your pizza soggy! The drier version is also easier to cut into (or buy as) thin slabs. Since you’re covering your whole bottom with cheese, these thinner slices are great to prevent a sure overload of cheese.

Cheese on top of a Chicago deep dish is no must, but if it’s there, it tends to be that same mozzarella cheese. Mozzarella cheese just browns really well in the oven, making it great for covering a pizza with it.

Sauce & sausage

There are a lot of different tomato sauces used on Chicago style deep dish pizzas. all have in common that they’re pretty moist. As opposed to flat pizzas, you don’t want the sauce to dry up during baking, you want it to stay more moist. Apart from that though, there are so many variations of sauce, that we won’t go into the details as much. Except for one aspect: the sausage.

Underneath the sauce, on top of the cheese, is where a lot of the extra toppings are added. Adding pepperoni is very common in most of the US. However, in Chicago a sausage meat variety tends to be the favorite topping. This topping is a mixture of ground pork meat with several spices (often including fennel). Why this is so popular? It might have had to do with the prevalence of pork in the past, but in all reality, no one really knows.


Steve Dolinsky, Pizza City, USA, link

Nick Kindelsperger, Why are Chicagoans so obsessed with Italian sausage on pizza? An investigation, Aug 21 2017, Chicago Tribune, link

The Pizza Bible, What’s the best pan for Chicago style deep dish pizza?

Sally’s Baking Addiction, How To Make Chicago-Style Deep Dish Pizza, 2014, link

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