We’ve all been there. Maybe it’s when you grab a coffee in the morning or when you finish up a dinner out with friends. Maybe it’s when you least expect it, like at the merch table at a concert. You tap your card, only to be confronted with the dreaded tip screen. There’s a lot of talk about how much to tip and if you even should tip (more on that later), but why do we add gratuity in America in the first place?

Nina Mast has the answer. She’s an analyst at the Economic Policy Institute, a left-leaning think tank in Washington, DC. The point of the tip is to make up the difference between the minimum wage and the tipped minimum wage. “The tipped minimum wage is the lower minimum wage that employers can pay tipped workers with the expectation that tips will bring their pay up to the regular minimum wage rate,” she says. “Under federal law, the tipped minimum wage is $2.13 an hour. So tipped workers need to earn an additional $5.12 in tips to bring them up to the federal minimum wage, which is $7.25 an hour.”

On this week’s episode of Explain It to Me, Vox’s weekly call-in podcast, we find out how this system began and why we still have it.

Below is an excerpt of our conversation with Mast, edited for length and clarity. You can listen to the full episode on Apple Podcasts, Spotify, or wherever you get podcasts. If you’d like to submit a question, send an email to askvox@vox.com or call 1-800-618-8545.

Where does tipping in America come from in the first place?

Tipping goes back to the pre-Civil War times in the US. There were wealthy Americans who were vacationing in Europe, and they noticed this practice of tipping where if you had good service, you gave a small extra fee on top of what you paid.

Then, tipping started to fade as a practice in Europe but persisted in the US. We can tie that back to the abolition of slavery. Once slavery was abolished following the........

© Vox