Maybe not quite 40 cups a day, but still, a LOT
Theodore Roosevelt was very likely America's most caffeinated president. Though other commanders-in-chief have been known to knock back a cup or two throughout their busy work day (the current White House resident abstains), the 26th POTUS famously enjoyed copious amounts of coffee from breakfast onward—a habit forged in childhood when he was given strong cups of coffee and puffs of cigars to help ease his asthma. This practice sparked Roosevelt's eldest son, Theodore Jr., to remark that his father's ideal drinking vessel might be "more in the nature of a bathtub," and presidential biographer Doris Kearns Goodwin to note that while she was unable to definitively confirm it, "One of [her] friends thought he drank 40 cups of coffee a day."
In the same CBS News interview, Goodwin touched on a possibly apocryphal, but still amusing legend that the president was responsible for one of the more famous advertising slogans of the last century. In 1892, after several years spent pursuing the perfect blend, entrepreneurs Joel Cheek and Roger Nolley Smith approached the food buyer of the Maxwell House Hotel in Nashville, Tennessee, and offered to give him 20 pounds of their coffee for free. The brew proved so popular there that it was served at Andrew Jackson's former estate, The Hermitage, when President Roosevelt came to visit in October 1907.
As the story goes, Teddy declared the Maxwell House coffee to be "good to the last drop." This declaration was supposedly overheard by Cheek, himself, and repeated on and off in advertising for decades—even after company executive Clifford Spiller admitted to making up the quote. (For the record, the local paper present at the scene reported that Roosevelt's comment on the coffee was, "This is the kind of stuff I like to drink, by George, when I hunt bears.")
This coffee fixation trickled down through the Roosevelt family, spurring Teddy Jr., as well as his brothers Kermit and Archie, their sister Ethel, her husband Richard Derby, and the president's cousin Philip to start a chain of coffeehouses in New York City. Their first Brazilian Coffee House opened in October 1919 and featured writing materials, dictionaries, and encyclopedias at each table, as well as on-premises roasted coffee and demonstrations by a staff hell-bent on educating Americans on proper coffee preparation. The chain, which eventually grew to four locations each named after a coffee region, was renamed "Double R Coffee House" in 1921 in order to avoid litigation from a competing shop. Maxwell House expressed interest in taking over the business, but the deal never materialized and in 1928, the business was sold to a couple who'd fallen in love at the original location on 44th Street.
The Roosevelt children came by their coffee obsession honestly. Breakfast at the family table included gallons of the stuff, alongside the president's favorite morning meal of hard boiled eggs (never medium or soft—he was very particular about that), as well as "great quantities" of homemade currant-studded rolls called "fat rascals," and large bowls of hominy served with butter and salt.