Since he also had to keep up at his day job of painting The Last Supper, Da Vinci downed gallons of coffee to stay awake during his all-night chicken soup experiments (this is all explained in the highly entertaining and absolutely worth every penny of the cover price book, The Da Vinci Cold).
Trying to reproduce his Jewish doctor's recipe was taking more time than he had, leading Leonardo to drastic measures. He concocted a potent enough coffee drink to keep him going day and night without the bother of sleep. This sketch of a lablel for a bottled version of his formula displays his faith in the product's effectiveness.
Legend has it that he gifted a barrel of his Leo's Last Sippa Espresso to a monastery and, when consumed with their morning meal, it caused every last one of the monks to break their vow of silence, yelping, "Yowza! Now that's some coffee!"
This moment in Da Vinci History is brought to you by my latest book, The Da Vinci Cold, or Chicken Soup for the Renaissance Man's Soul, from the mighty juggernaut that is the Now What Media empire, and is on sale now at Amazon.com and finally at Barnes & Noble where they're offering it at a pretty sweet discount.