Which ingredient is common to all types of Freezes?

The correct answer is espresso, as it is the key ingredient that distinguishes Freezes within the Dutch Bros menu. Freezes are known for their icy, blended texture and main flavor profile, which comes from espresso. This ingredient provides the foundational coffee flavor that sets Freezes apart from other blended beverages.

While milk, coffee, and sugar may be present in various drinks at Dutch Bros, they are not universal or defining ingredients specifically for Freezes. Milk can vary between drinks and is not a standard component of every Freeze, while regular coffee can be used in some mixes but is not a defining base for Freezes. Sugar, although often added to enhance sweetness, is also not a required ingredient for all Freezes. Thus, espresso emerges as the common and essential component that characterizes this specific type of beverage.