Which of the following determines the serving strength of a spirit?

The serving strength of a spirit is fundamentally determined by the dilution process before serving. This refers to how much the spirit has been diluted with other ingredients or mixers, which directly affects its alcohol by volume (ABV) when served. For example, adding water, soda, or juice to a spirit reduces its overall alcohol content, influencing the drink's intensity and flavor profile.

The other factors listed, while they can influence the drinking experience, do not inherently change the spirit's serving strength. The temperature of the spirit can affect how we perceive its flavors and aromas but does not alter the alcohol content. Similarly, the amount of ice used may cool the drink and cause some dilution as it melts, but it’s the initial dilution process that sets the serving strength. The type of glass used also affects presentation and aesthetics rather than the actual strength of the spirit itself. Therefore, the dilution process before serving is the primary factor that determines the serving strength of a spirit.