This glass he chooses to savor, rather than slug back. At least, that's the official press release.

"If there was an emergency, and you needed medical attention, what do I need to know?" It, perhaps, isn't the most romantic question, but it is the one he needs answered. It bothers him, not knowing these things. It's why he nags Spock at every opportunity to get him more information on Vulcan physiology.