Pizza box

Traditional way of folding a pizza box

Most packaging for the transport of pizzas is made of cardboard, as this is both cheap, easy to work with and lightweight while maintaining adequate structural integrity to hold and deliver pizzas. Both solid fibre board and single wall corrugated board are used. The corrugated cardboard in use is often of the E flute size (micro or fine waves with a flute pitch of 1.0 to 1.8 mm), but thicker B flute cardboard with a flute pitch of 2.2 to 3.0 mm are also used.[9] Not only the geometric construction of the cardboard determines the stability of the box, but also especially the type of paper and its grammage. For the liner mostly containerboard is used on the inside of the box. This does not only make the box stable, it becomes more resistant against humidity and oil as well. To reduce the space needed to store the packaging to a minimum, the pizza boxes are folded just before use out of flat blanks. The required storage space depends very much on the different thickness of the material.[9]

Pizza boxes made from solid fibre board take up about half the space the boxes with E flute size cardboard need, and a quarter of the space of those made of B flute size cardboard. Apart from the material itself, the stability of the box is determined by the form it is folded into. The type of pizza box with flaps firmly attached to the side walls that are folded into the front wall has established itself as the standard. In this case, the walls of the box are connected at the edges and this increases its stability. The traditional way of folding the box is an example of this folding type. Its disadvantage is that the walls of the box rise vertically which makes cutting the pizza in the box with a pizza cutter more difficult.

The opening on the side of the box allows some moisture and heat to evaporate.

The pizza box is supposed to allow the transport of a baked pizza with the minimum loss in quality possible. This means the box has two tasks to fulfill that are not easy to combine: On one hand, the box should insulate as well as possible against the cold air outside, the occasional wind and heat radiation, in order to keep the pizza warm. To reduce heat flow, the box has to close as firmly as possible to keep the warm air inside. Consumers consider a temperature between 70 and 85 °C (158 and 185 °F) to be ideal for pizza consumption. On the other hand, the box should keep the pizza from getting soggy, so that the crust and the covering are crisp on arrival.[10] To ensure this, the condensation caused by the pizza must be let out (airing holes and some diffusion through the cardboard) or absorbed by the box. However, this results in the pizza getting cold.[8] Pizza boxes made of single-wall corrugated board that are not equipped with additional insulation cool the transported pizza down too far after just ten minutes.[10]

The oil in the pizza dough contaminates untreated corrugated cardboard, making it unsuitable for paper recycling.[8] To prevent a change in the taste of the pizza through the material of the pizza box, and simultaneously to stop the cardboard from getting soggy, the pizza boxes have a thin coating of aluminum foil on the inside.[11] Another possibility is to lay the pizza on either aluminum foil, a mixture of corrugated cardboard and blotting paper, or waxed paper. However, this changes the thermodynamic properties of the pizza box considerably. The pizza crust cannot give up any humidity downwards, meaning the layer beneath does not only impedes fat from trickling down but also steam.

In the US, many pizza boxes include a spacer made of heat-resistant plastic (usually polypropylene) placed in the middle of the pizza called the pizza saver (also known as "package saver", "box tent", "pizza table", or "pizza lid support").[12][13] This stops the box lid from touching the pizza and prevents cheese and toppings from sticking to the lid when it is being delivered.[2] The pizza saver's origin goes back to a 1985 patent by Carmela Vitale.[14][15] The pizza saver is often criticized for being a waste of resources as it is only used once and then thrown away.[16]

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  A pizza saver
• 
  A pizza with a pizza saver

Domino's Pizza motor bikes that are used for pizza home delivery in Goa, India, with transport boxes mounted atop

There are special padded transport bags and boxes for delivery. Some of these bags can be heated in order to keep the temperature at the desired level. Mostly, they can either be plugged to a socket or powered by the 12 volt car battery. This means that the insulation of pizza boxes themselves is less important. Carry bags insulate best when their lid is connected to the rest of the bag on one side and the remaining three sides can be attached to lid by a zip. A bag can contain about three to five pizza boxes.

The pizza boxes by Pizza Hut in Morocco and other countries have a thermometer indicator on the outside which color codes the temperature of the pizza inside. When the pizza is hot, the indicator shows the words "HOT" in red letters on a white background. However, if the temperature of the pizza goes below a certain value, the "Hot Dot" turns black and the words are no longer legible.[17]