Bottles come in all different shapes and sizes.
A key decision when choosing a bottle is: Round or square? The shape of the bottle impacts every stage, from manufacturing to filling and packing to shipping to shelf presentation and use.
Glass and plastic bottles are generally blow molded. A mold is clamped around a glass or plastic tube. Compressed air blows it out to the shape of the mold. The distance from the center to the sidewall is uniform in a round bottle.
The distance to the corners is greater than to the walls in a square bottle. This makes it more difficult to get a uniform distribution of the material. Corners concentrate stress, creating a weak point that does not exist in a round bottle. The need to assure minimum wall thickness and to compensate for corner stress means that a square bottle uses about 8% more material than a comparable size round bottle.
Filling and packaging.
Round bottles flow more smoothly on the packaging line and are less subject to jamming. They are easier to accumulate and de-accumulate and separate into multiple lanes. Labeling is simpler for round bottles since there is usually no orientation required.
Labeling is simpler for round bottles since there is usually no orientation required.
When round bottles are packed in a carton or case, there is a natural air vent between the round bottles and the case walls corners. Square bottles don’t have that natural air vent and can form an air cushion going into the carton or case. This can slow loading speeds unless vented somehow.
Square bottles use about 18% less space than round bottles, with no wasted space between. This reduces the case size, plastic wrap, warehousing, and transportation space. All of these cost money. Even small gains add up quickly.
“Nothing happens until somebody sells something.” None of the benefits of square vs. round bottles matter if the product doesn’t sell.
Some of this is pure shelf aesthetics: Square bottles tend to display better on the store shelf because of their full, flat, easy-to-read front panel.
Some is customer expectation: Most wine comes in round bottles. Selling wine in a square bottle could be an uphill battle.
Some is just touch and feel: Round bottles fit the hand better, especially smaller hands.
So, is round better than square? Of course. The harder question is what does “better” mean in each instance? The reduced shipping cost may offset the higher material cost if shipping square water bottles into the US from Fiji. Not so much if shipping across town. The balance of reasons will be different in every instance. You need to decide but you can only decide when you know all the reasons for and against each.
Known as the Changeover Wizard, John R. Henry is the owner of Changeover.com, a consulting firm that helps companies find and fix the causes of inefficiencies in their packaging operations. He has written the book, literally, on packaging machinery (www.packmachbook.com) and is the face and personality behind packaging detective KC Boxbottom, the main character in popular articles on the Packaging Digest website. He can be contacted at [email protected].