Meh. I see potential but you sort of come off as a jaded elitist.
I'm trying to employ humor. Is there anything you would recommend?
Hmm. Honestly, I didn't get much humor from my read of it. I like the idea and I think you have laid the ground work for an effective piece. Like para said, I think specifics would really help. If you're going to claim your a beer snob, sound like a beer snob! Where you were talking about the hops and the citrus additives was the closest you came to this.
"Popular beers these days typically offer little in terms of taste, and instead offer low-carbohydrate and tasteless charlatans. I respond to these commercial imitators by shunning the aisles in which they reside, and remain loyal to the true faith of quality craft beer."
This is the part I don't like. Maybe because you say "popular" beers and "commercial" imitators. To me I feel like that alienates the reader. You don't want to give the impression that you're a pompous hipster. I realize that the whole point of the essay is wrapped into this point, so obviously you're walking a tight line here.
Also, I think a bit of the phraseology is a bit colloquial for a 250 essay.