A Shamrock Shake is a sweet, mint-flavored green milkshake that is a product of McDonald's® restaurants. The coloring of this dessert beverage is light Irish green, as Shamrock Shakes are meant to acknowledge Saint Patrick's Day on March 17 of each year. Saint Patrick's Day is an Irish Catholic feasting holiday that honors the patron saint of the same name. Saint Patrick's Day is a national holiday in the Republic of Ireland and is celebrated by eating, drinking and wearing the color green. Green is the unofficial, customary color of Ireland and the shamrock, a species of clover with three leaves, is Ireland's unofficial, customary symbol.
The McDonald's® Shamrock Shake is available year round in Ireland, but not elsewhere. It was sold year round in the United States and Canada until the early 1990s. McDonald's® first introduced the Shamrock Shake in 1970. Some Canadian and American McDonald's® restaurants include the shake on their menus for a limited time around Saint Patrick's Day. At these restaurants, the shake is offered in the middle or at the end of February.
Shamrock Triple Thick® Shake is the full name of the McDonald's® beverage. The small size measures 12 fluid ounces (360 ml) and contains 420 calories and 0.353 ounces (10 g) of fat. The main ingredients are reduced-fat vanilla ice cream and Shamrock Shake Syrup. The ice cream used for Shamrock Shakes contains milk, sugar, cream, non-fat milk solids and corn syrup solids plus flavoring, additives and preservatives. The Shamrock Shake Syrup contains high-fructose corn syrup, corn syrup, water and sugar as well as natural flavor, preservatives and food color.
Since not all McDonald's® in the United States and Canada offer Shamrock Shakes each March, this had led to online petitions and requests to the McDonald's Corporation® to bring the shake back. The manager of each McDonald's® is permitted to decide if his or her store will sell the Shamrock Shake each year. In Canada, the Shamrock Shake was available in March 2008 after being unavailable for five years. Due to the scarcity of the product, people began creating their own recipes to try to make the McDonald's® Shamrock Shake at home. These homemade recipes vary widely but most use vanilla ice cream and mint extract as the base.