I think he liked the rebel aspect of doing something "illegal" but didn't like the taste or impact of alcohol. His journal reads: "I bought that flask in the mall and I had a friend fill it up w/ scotch whiskey, only had about 3 swigs in the 3 weeks I had it. plus monday I gave my T and IC to Vodka, just in case. I never really did like alcohol, just wasn't my thing, but It felt good to just have around..."
Three swigs in three weeks pretty much says it all. As does Eric saying it "felt good" to keep alcohol around just for the rebellious thrill of having it.