The Egg is a dome, a pizza oven is a dome. What is different?

Ancient oven

Wood fired pizza ovens have been evolving for centuries, maturing into the igloo shapes made of fire bricks that we know today.  These ancient, simple, ovens have cooked outstanding bread and pizza for centuries.  What is so different from a Big Green Egg or Kamado style grill? It may be odd to think of it this way, but the evolution of the oven actually drove the development of the food.  Pizza looks like it does because hot, domed ovens were very good at baking the top and bottom of a flat dough.  The floor of these stone ovens was hot from the radiant energy of the ceiling. Moist dough was placed on the floor of the oven and the stone surface absorbed moisture creating steam, heating the bottom before drying out and then crisping the crust. The dome shape of the ceiling reflects heat down onto the top of the bread or pizza.  The heavy, thick walls of the oven accommodate high temperature and keep it very steady.  There is actually a chemical reaction of yeast trying to expand as it hits a certain temperature. The gluten allows the dough to stretch into bubbles before the flour hardens and gets crunchy.  If the dough heats up at the wrong rate, or inconsistently, the wonderful bubbles do not fully form and the character is lost.  Wood fired ovens with heavy walls and wood as fuel served as a platform to bring all of this magic together at a precise rate.

The Big Green Egg style cooker, on the other hand, evolved with other kinds of food items. Foods of Asia are different from foods of the Middle East and Italy. The dome shape does reflect heat, and the walls can stand up to high temperatures. Everything else about this traditional Kamado style oven however, makes cooking pizza challenging.  The temperature control in a kamado style grill is achieved by controlling the airflow. The dome must stay down to cook effectively. (If your looking, you're not cooking- right?) and the ventilation must be controlled. The fire/heat is underneath the pizza stone.  When you lift the lid to check the pizza, you actually cool off the top of the oven chamber. Even when closed, the chimney is at the top of the dome so the the hottest air escapes through the top. If the Kamado style oven was the go-to for baking in the Middle East and Italy, we would probably not have pizza today.

This is why we developed the Pizza-Porta.  It is a simple device that radically alters the cooking chamber.  We don't suggest that the Big Green Egg is unable to make pizza.  What the Pizza-Porta does is modify the cooking chamber so that it performs up to the level of a wood-fired pizza oven.  Pizzas will be cooked evenly top and bottom, the dough will rise properly, the temperature is adjustable and consistent, the first and last pizza will cook the same, and you will have a relaxing cooking experience.  Here is a simple explanation in pictures.

This is a pictorial of the cooking cycle for a Big Green Egg or other Kamado style grill in the conventional manner. Opening the lid will affect the dynamics of the temperature and the fire.

When you open the lid to add, check or retrieve a pizza, your fire is fully vented. This allows all the heat to escape the dome and it allows the dome to actually cool off.  Even cooking pizza when the lid is closed is not optimal since the heat passes quickly around the pizza and vents out the top since the vent must be wide open to reach high temperatures. Pizza cooked in this conventional manner receives most energy through the stone because it is so much hotter than the dome. This misalignment of temperature causes the crust to cook fast (and often burn) before the top of the pizza gets cooked.

A wood fired pizza oven has a completely different design.

brick oven - Image: Forno Bravo

This pizza oven employs three forms of heat to cook a pizza: conduction, radiant, and convection.  The fire is built to the side of the pizza and because the heat must exit from a point below the dome, the heavy dome collects, stores, and radiates heat to the bottom of the oven.  The mass of these ovens (the roof and insulation in a 900 degree oven can be 1 foot thick) keeps the temperature very steady. The crust cooks on the bottom from the heat conducting into the crust from the floor. The top of the pizza cooks from radiation off of the dome, and the convection of the heat swirling around as it crosses over the pizza to exit the chimney. With this design, the floor and the dome temperature are well aligned - within 100 degrees.  These ovens are designed specifically to handle and maintain temperatures from wood burning with wide open venting.

Adding a Pizza-Porta to a Big Green Egg/Kamado grill solves pizza cooking challenges.

Heat flow in a Pizza-Porta

After adding the Pizza-Porta. the fire is still below the pizza, but the plate setter diverts the heat around the pizza stone controlling the conductive heat.  The top vent remains closed for cooking so that the heat builds in the dome, heating it to create the radiant energy needed to cook the top of the pizza.  The heat flowing around the dome is trapped because it can only escape via the vents positioned lower than the dome.  This airflow of heat also cooks the top of the pizza via convection as it flows out the vents.  When the front door is opened briefly, there is an increase in airflow, but the heat trapped in the dome keeps the temperature steady. With the door closed the airflow is balanced keeping the temperature under control.

By changing the dynamics of the cooking chamber, the Big Green Egg/Kamado grill cooks like an authentic pizza oven.

So all of this geeky information is great, why should you care?  By adding this device to your grill, you can take your pizza to the next level.  You can cook restaurant quality pizza all night long.  Since the temperature is balanced you can cook at 600F+ resulting in <5 minute pizza cook times.  This steady burn is more efficient so a single load of charcoal can last 3 -1/2 to 4 hours.  And, you won't have the stress of hoping the unseen pizza is done and not burned each time you lift the lid.

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Cortlandt