Why do paper bags have a zig-zag cut at the top?
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Listener Jess Schurtman asks:
Why do paper grocery bags and some other paper sacks have a zigzag cut top? I know with fabric, pinking shears are used to cut it that way so the fabric doesn’t fray as much, but what’s the purpose with paper? Or is it purely decorative or tradition?
We often take the simplest designs for granted.
The unassuming brown paper bag, which we use to carry our groceries or our lunch, has serrated edges at the very top. You can call it a zigzag pattern or a “pinking cut.” Those cuts are there primarily for safety reasons, but there are also decorative benefits to the zigzag, experts told us.
Those edges help consumers to avoid paper cuts, said Adrianne Tipton, the chief technology officer for Novolex, a company that manufactures packaging products.
“If you cut the paper with a straight clean edge, it is more prone to cause paper cuts due to the sharpness of the paper,” she said.
The zigzag pattern doesn’t cost any additional money, nor does it introduce any manufacturing complexities, said David Dobrzykowski, a professor of supply chain management at University of Arkansas’ Sam M. Walton College of Business.
In fact, it makes peoples’ lives easier. Cutting paper with a serrated edge allows manufacturers to make uniform bags, said Roger Beahm, a marketing professor at the Wake Forest University School of Business.
“If paper bags are finished with a straight cut, there is a tendency during the cutting process for some bags to tear ahead of the cut line as the blade moves through the paper. These tears can result in an uneven and potentially unsightly finish to the edge of the bag, which may render them unusable,” Beahm said.
And the decorative flair of the zigzag pattern doesn’t hurt either. Having serrated edges can be “eye-catching” and add “a touch of quality” to the bag, Beahm said.
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