Possible Clues:

• Stimulating substance in coffee
• Stimulant in coffee
• The stimulant in coffee
• Loud music at a foreign restaurant outside will keep you awake at night
• Stimulant
• Small restaurant over top finca in Spain can keep you awake at night
• Cause of a crash, perhaps
• Diner imbibes fine new coffee ingredient
• Mild stimulant
• The drug in coffee