Site Search

Structural Options
Pros & Cons

Pizza and side-item box technology affords many options. Here we describe some of the basic ones and list the advantages and drawbacks of each.

Paper vs. Plastic. Pizzeria, restaurant, and foodservice packaging comes in two basic materials: Paper and plastic.

Paper typically derives from cellulose, or wood fiber, which of course comes from trees. Paper packaging is often divided into two groups based on two types of board used in making it: (1) paperboard, also known as boxboard, cartonboard, and cardboard and (2) corrugated board, also known as corrugated fiberboard, corrugated paperboard, and combined board. For decades the public has referred to corrugated board as “cardboard,” but this is technically incorrect. (If all this seems confusing and contradictory, that's because it is. The paper industry has very few definitive terms and is replete with inconsistent and conflicting terminology.)

Paperboard is sometimes used to refer to a single sheet of very thick paper. It comes in many forms having various attributes. Common examples include chipboard and solid bleached sulfate, or SBS, board. The original pizza packaging was made of paperboard, and some pizza boxes still are today. The main advantage of paperboard is that it's cheap. (NOTE: It's important to note that the term "paperboard" is sometimes used to refer to all types of board derived from paper pulp, including corrugated board. So the definition of "paperboard" is not precise.)

Like paperboard, corrugated board also comes in many forms. The most common is single wall board, also known as double face board. It's what's used for most pizza boxes. It consists of two outer sheets of flat paper, called facings or liners, glued to a fluted, or corrugated, inner sheet, called medium. The paper used for the facing or liner is called linerboard. The paper used for the medium is called medium.

When only one facing is glued to a medium the resulting product is called single face board. Corrugated board can be imparted with various characteristics. This is achieved through varying the type and thickness of paper used in making the board. In addition, the application of coatings or treatments can further impart unique attributes. This includes moisture-resistance, grease-resistance, and fire-resistance, among other things. Compared to paperboard cartons, corrugated pizza cartons have many advantages, including stacking strength, product protection, heat retention, and opportunity for shape variation.

Plastics comprise a host of synthetically-made moldable materials. Examples of common plastics used in foodservice packaging include polyethylene (PE), polypropylene (PP), polystyrene (PS), and expanded polystyrene (EPS), a rigid foam product which is often incorrectly referred to as "Styrofoam," a trade name for an EPS construction material made by Dow Chemical.

The advantage of plastic packaging is that it can be molded into special shapes and colors and can be designed to be 100 percent leak-proof. The advantage of paper packaging is that it never develops product-sogging condensation build-up inside the carton, can support stunning graphics and Graphics-Structure Integration, and also is usually more cost-effective.

Corrugated board is far-and-away the most prevalent material used in pizza packaging today. So the rest of this discussion pertains to corrugated pizza boxes.

B-flute vs. E-flute. Corrugated board can be produced in various thicknesses, or heights. This is accomplished by shaping the medium (or inner paper) of the board into any of several flute heights during the production, or corrugating, process.

The higher the flute, the thicker the corrugated board. To designate the various flute heights, or board thicknesses, the corrugated paperboard industry applies letters and, as a result, has derived designations such as A-flute, B-flute, C-flute, E-flute, and so on.

Most corrugated pizza cartons come in either B-flute or E-flute board. B-flute board is about 1/8-inch thick, E-flute is about 1/16-inch thick, or half as much. Some folks assume that B-flute, because it's thicker, comes with heavier paper, but that's not necessarily so. The flute size has nothing to do with paper thickness, or weight. It's possible to have B-flute made of flimsy thin paper and E-flute made of sturdy thick paper. The advantages of B-flute are that (a) it tends to warp less from pizza steam than does E-flute and (b) some folks believe that the thicker board connotes higher quality. The advantages of E-flute are that (a) it saves almost 50 percent in box blank storage space over B-flute and (2) it tends to print up slightly better.

In recent years a flute even thinner than E-flute has emerged. It is known as F-flute, or microflute, and is used in foodservice packaging in place of E-flute and, in some cases, in place of paperboard (e.g., chipboard and SBS).

In certain box structures, B-flute makes a nicer carton. In other box structures, E-flute works best. It's also worth bearing in mind that it's possible to mix and match. A company can have its larger boxes (ex., 14-inch and 16-inch) made of B-flute and its smaller ones (10-inch and 12-inch) made of E-flute.

Some folks also assume that B-flute, because it's thicker, retains pizza heat better. However, research by at least one box manufacturer refutes this.

An important factor to the pizza industry is the stacking strength, or crush-resistance, of the box — or the carton's ability to hold a steamy hot pizza and resist crushing when several other loaded pizza cartons are placed on top. Stacking strength is affected by (a) the structural design of the carton and (b) the flute and paper weight of the corrugated board. As regards the latter, heavier paper weights tend to have more crush-resistance than lighter paper weights and B-flute board tends to have more crush-resistance than E-flute. However, structural design plays the biggest role. It's possible for a particular box design made of lighter-weight E-flute board to have greater stacking strength than another box design made of heavier-weight B-flute board.

Paper Weight. Various weights of paper can be used for making corrugated board. The heavier the paper, the stronger the corrugated board. Also, the heavier the paper, the more expensive the board. So, selecting the optimum paper weight for making a particular corrugated board is a balance between achieving desired carton functionality while not “over-engineering” the carton and, thereby, wasting money. In the packaging industry, the term “basis weight” refers to paper weight. It is the weight of a given area of paper.

A typical corugated board weight used for pizza boxes is 125 lb test board which has a combined facings basis weight of 52 lb, or 26 lb basis weight per liner.

White Paper vs. Kraft Paper. Two basic types of linerboard exist for making corrugated board for pizza cartons: White paper and kraft, or brown, paper. The advantage of white paper is that it displays color printing better. The advantage of kraft paper is that it's less expensive. Some folks feel that white projects a better image; others believe that brown projects a better image. Many companies use white for the outer liner to create optimal color contrast for printing and brown for the inner liner to save money. Others do the opposite, putting the white liner on the inside and brown on the outside. They feel that a white liner on the inside provides a cleaner-looking surface for pizza contact. Others point out that when brown is used on the inside it camouflages the sauce and grease mess on the bottom of a pizza box.

Paper Coatings. Various coatings and treatments can be applied to paperboard to achieve various results. In food packaging, water-resistant and grease-resistant coatings can substantially enhance carton performance. These can be applied to either of the liners (outer papers) or to the medium (inner paper).

Postprint vs. Preprint. In postprinting, the corrugated board is printed during the converting process, or just prior to the board being die-cut into a box blank. In preprinting, the liner (or outer paper) is printed prior to it being made into corrugated board. As a rule, better quality printing (i.e., finer detail and registration) is achieved with preprint. However preprinting requires substantial volumes. More economical printing is achieved with postprint. Most pizza boxes are printed by postprint.

Two-piece vs. One-piece. Cartons can be classified into two types: Those in which the cover and tray portions are separate units, called a two-piece carton, and those in which the cover is attached to the tray portion, called a one-piece carton. As regards pizza, we don't know of any advantage for the two-piece type. The advantages of the one-piece type are that (a) it tends to be more rigid and less prone to accidental cover opening and (b) in the case of paper packaging, the one-piece carton typically costs less than the two-piece because it uses less material.

Folding vs. Non-folding. Regarding paper packaging for pizza, one-piece cartons can be further classified into two types: Those requiring folding or set-up, called folder or folding cartons, and those that don't, typically called clamshells. The obvious advantages of clamshell cartons are (a) they don't require in-store folding time and (b) they consume less storage space than do stacks of pre-folded boxes. The advantages of folder cartons are that (a) they're substantially less costly than clamshells (as much as 30 percent or more), (b) they tend to be sturdier or have greater crush-resistance than clamshells, and (c) they can be set up on their side on a shelf (such as above a cut-table). Since most box-folding is performed during “idle time,” most pizza companies opt for the cost savings of folder cartons.

Connected Corner vs. Non-connected Corner. Folder cartons can be further classified into two types: Those that have one or more connected corners, called a connected carton, and those that have no connected corners, called a non-connected carton. A connected corner is a corner in which two adjacent walls are attached to one another. This type of corner stays in upright position when the box cover is open. The traditional (walker lock) pizza box is an example of a connected carton. A non-connected corner is a corner in which two adjacent walls abut one another but are not attached. This type of corner “comes apart,” or allows the adjacent walls to lay back, when the box cover is open. The Chicago folder and Domino's Pizza D-type boxes are examples of non-connected cartons.

We don't know of any particular advantage of using a connected carton for a pizza box.

The advantages of non-connected cartons are (a) they allow in-box pizza-cutting with a rocker knife, (b) they allow in-box pizza-cutting with a pizza wheel without having to jostle the pizza to center it or having to run over the side walls with the cutter, and (c) they can be easier for a consumer to dispose of.

It also should be noted that Correll Concepts has hybrid technology which consists of box structure that can be folded up into either a connected carton or a non-connected, at the choice of the box-folder or pizza company.

Non-locking Cover vs. Locking Cover. The traditional pizza box has a non-locking cover, meaning that the cover does not interlock with the tray portion of the carton. Most other boxes have an interlock between the cover and tray. A typical interlock involves a cover flap inserted within a slot in one of the flaps or walls of the tray. The advantage of a non-locking cover is that it can usually be closed a little faster than a locking cover by a second or two. The advantage of the locking cover is that (a) it eliminates accidental cover opening and (b) it creates a more-rigid feel to the carton.

Interior Cover Flaps vs. Exterior Cover Flaps. Pizza cartons can be made with cover side flaps that reside either on the inside of the tray or on the outside. The traditional pizza box uses interior cover side flaps, as do most other cartons. However, at least one carton (i.e., the Domino's D-style box) uses exterior cover side flaps. In fact, most boxes can be equipped with exterior cover flaps, if so desired. The advantage of interior cover side flaps is that the box tends to be easier to fold and to close (although not always). The advantage of exterior cover side flaps is that the flaps don't ever contact the pizza and, therefore, never result in product crushing.

To avoid having interior cover side flaps contact the pizza, some box manufacturers install a notch along the bottom edge of the flap. This works for thin pizza but not necessarily for thick.

It's also possible with certain box designs to eliminate the cover side flaps altogether.

Square Shape vs. Non-square Shape. For a discussion of square vs. non-square carton structure, see the Square vs. Non-square section.

If you have any questions, or would like some help figuring out which structura

l options would be the best fit for your operational system and would provide the most benefit for your company, contact John Correll - 734-455-5830 or email john@correllconcepts.com. Please note — Correll Concepts is a packaging design specialist, not a box manufacturer.