When he leaves his native Canada on business, Dave Zettel can’t be sure that the bartenders wherever he is headed to will know how to make his favorite drink. So he packs the ingredients. Mainly, this means stowing away a few containers of Clamato, the mix of tomato juice, sugar, spices and clam broth produced by Mott’s.

Zettel, 31, isn’t an eccentric. His favorite drink is the favorite drink of many Canadians. It’s the Caesar, a spicy and piquant mixture typically composed of vodka, hot sauce, Worcestershire sauce, various spices and garnishes and, most critically, Clamato or some equivalent.

On a 2015 trip to Thailand, Zettel hauled all the ingredients. He ran into a fellow Canadian there. “As soon as I brought out the Mott’s Clamato, he was the happiest man alive,” Zettel said. “And then we had Caesars on a random Thai beach.”

At home in Yellowknife, in the Northwest Territories, Zettel doesn’t worry. A Caesar is always within reach there, as it is across the rest of the country.

“I’d say it’s our national cocktail,” he said. “You get the odd person who doesn’t like them.”

Should you find yourself in a town without bars or restaurants, don’t worry. Many Canadian homes can provide emergency Caesar service.

“Caesars taste like home,” said Christian McPhee, 45, who lives in Toronto and does information technology work in the financial industry. “It’s like comfort food for Canadians. For as long as I can remember, Caesars have been a part of my family’s get-togethers. My grandmother was the first I remember in my family always having them. My family had them at every beach bonfire, Canada Day celebration, long weekend and Sunday brunch.”

“They’ve always been there,” he added.

Well, not quite always. The generally accepted history is that the drink was invented in 1969 in Calgary, Alberta, by a restaurant manager named Walter Chell. (There is, however, evidence of similar clam-and-tomato-juice drinks that predate it. The drink’s most obvious antecedent is the Bloody Mary, which has a longer history, though the Canadians interviewed for this article tend to think of that American favorite as a poor and distinctly less tasty relation.)

The Caesar took off, and, with it rose the fortunes of Mott’s Clamato, which was introduced in the late 1960s. Though most Clamato is produced in the United States, one-third of its North American sales are in Canada. Most of that is poured into Caesars, according to Mott’s.

Unlike the Bloody Mary, the Caesar isn’t consigned to the morning hours. “In Canada, anytime is a good time to drink a Caesar,” said Darcy O’Neil, a cocktail writer and former bartender who lives in London, Ontario. (And don’t call them Bloody Caesars, as many Americans do. Rookie mistake.)

Though the Caesar has long been popular, there are signs of a recent jump in consumption.

“When I first started bartending, it was few and far between that people ordered a Caesar,” said London Richard, 32, a Calgary bartender with 14 years of experience. “Over the last eight years, it became huge. I think people started realizing there’s so much potential behind it. It’s such a versatile cocktail. There are a million possibilities.”

Richard lets that potential run wild at Sorso, a restaurant near Calgary where he is an owner. He offers a “Caesar bar” that allows customers to select which spirits, spices and garnishes go into their drinks.

Mott’s has encouraged that creativity by introducing additional Clamato flavors; Pickled Bean came out last year. There are also competing tomato-clam juices on the market, including Walter Craft Caesar Mix, which labels itself as an “all-natural” and “artisanal,” and Simp’s Serious Caesar Mix, which is vegan.

So far, however, all this enthusiasm has stopped at the U.S. border. The Caesar stubbornly remains a Canadian phenomenon.

“We assume everyone knows and loves Caesars,” McPhee said. “It’s not until you leave Canada that you realize no one else knows what they are.”

THE CAESAR COCKTAIL

• 1/2 teaspoon celery salt
• 1/2 teaspoon garlic salt
• 1/2 teaspoon steak seasoning
• 1/4 ounce lime juice (from about 1/2 a lime), and more for coating the rim of the glass
• 2 ounces vodka
• 2 dashes Worcestershire sauce
• 2 dashes hot sauce
• 4 ounces Mott’s Clamato or other tomato-clam juice
• A pickled vegetable (green beans are popular), for garnish

Blend the celery salt, garlic salt and steak seasoning. Dip the rim of a pint glass or Mason jar in lime juice, then dip it in the spice mix to create a spiced rim.

Add the vodka to the glass. Fill with ice. Add the Worcestershire and hot sauces, and the lime juice. Fill glass with Clamato. Stir briefly, about 5 seconds. Garnish with a pickled vegetable of your choice.