What must be done to the glass before adding the drink in the Long Island Tea Jameson recipe?

To make a Long Island Tea with Jameson, filling the glass with ice is essential before adding the drink. This step is crucial because it helps to chill the beverage, maintain the right temperature, and dilute the drink slightly as the ice melts, which can enhance the flavors and balance the strong spirits typically found in a Long Island Tea. Using ice not only improves the overall drinking experience by keeping the cocktail refreshing but also allows for better mixing of the ingredients as they are poured over the ice.

While other options, such as chilling the glass or washing it, may have their own merits in different contexts, they do not directly impact the immediate preparation and enjoyment of this specific cocktail as effectively as filling the glass with ice does.