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Why Is Licking Envelopes Still a Thing?

It's 2015 and we're still licking envelopes with our tongues like a bunch of barbarians.

Despite multiple suggestions, I am not going to question whether physical mail should still be a thing. We may not send handwritten letters as a primary form of communication anymore, but we still need stuff mailed. Financial documents, legal forms, regrettable wine-drunk Etsy purchases, you catch my drift.

No, I'm here to investigate a very specific part of mail: envelopes that you have to lick to seal.


Seal-and-lick envelopes were a pretty sweet invention when they first landed in society's collective inbox. Prior to that, everybody either used glue, wafer seals (they're like little stickers), or sealing wax, according to Maynard Benjamin, the president of the Envelope Manufacturers Association and an envelope historian.

Being able to seal an envelope using just your tongue was a huge timesaver when the technology was first invented. But that was in the 1840s, and envelopes haven't changed very much since. It's 2015 and we're still licking envelopes with our tongues like a bunch of barbarians.

While other means of sealing envelopes have emerged—such as peel and seal envelopes, where you peel off a covering to reveal an adhesive strip that you then press down—the old lickable letter sleeve is still the most popular style of envelope by far, according to Benjamin. The lickable strip, which is called the gum, is usually dextrin-based adhesive, Benjamin said. Dextrin adhesives are made from potato or corn starches, which makes the glue safe to lick.

Of course, you can use a sponge to wet the strip; this is common for people who have a lot of envelopes to seal, like wedding invitations. There are even people who refuse to lick envelopes out of fear of a tongue paper cut (or in some cases a rather tenacious urban legend about cockroach eggs). But tongue or sponge, the effort required is about the same. If we've already invented an easier system, why the hell do we still have to lick paper to seal it shut?


The answer, as is so often the case, is manufacturing.

Bulk mailing companies have already invested in machines that automatically wet and seal thousands of envelopes a day, so it's understandable that they wouldn't want to switch over to peel-and-seal. And envelope sales for bulk mailing and shipping, for companies like Amazon and eBay, are on the rise: Benjamin said envelope sales overall grew by about 8 percent last year, with 12 percent growth in the bulk mailing sector.

"Most mailing applications today use a wetting device, so people don't lick them. They're wetted and it's a machine that does that," Benjamin explained.

Meanwhile, the greeting card and letter envelopes we're most familiar with have stayed pretty steady—Benjamin told me 7 billion greeting cards are sold each year—but since these are usually sealed individually in small numbers, nobody really gripes too much about having to use their tongue.

And some sealing technology that predates the lickable envelope has actually reemerged: you can purchase decorative wafer seals and even wax sealing kits.

As long as we still use envelopes, which, granted, may not be for that much longer, we're just going to have to deal with sealing them with our tongues. It's a really old piece of technology, but given how infrequently the average person actually has to seal an envelope, it's not a huge inconvenience.

"It's pretty easy stuff," Benjamin said. "It's an old communication device, but it works,"