Question: To Drink or not to Drink?

My family and I just got back from a nice trip to HIlton Head Island. It was a great time. Like most trips, this one included a Sunday away from home, and consequently away from church. We have made it a habit, and the boys have come to expect that if we're away, I will lead "church" on Sunday before we head out for the day. This last trip was no exception and I knew what we should do during Sunday morning. I went in search of a passage that would speak about the Lord's creation and how it's all His and that when we see the beauty of the earth, we should be, in our hearts, praising God for what he has created. (By now, you're wondering what this has to do with the title of the post, aren't you?) Well I came across a great passage, Psalm 104, that articulated so much of what the boys would be seeing in the ocean and on the land as we were on this vacation. I told them that church was going to be really long because we should continue worshiping God for his creation while we're observing and enjoying it. Psalm 104 lays this out nicely. It was a perfect passage to read and discuss with the family. I would encourage you to read it as well. But here's the interesting part. (Verses 14 and 15):

He makes grass grow for the cattle,
and plants for man to cultivate—
bringing forth food from the earth:
wine that gladdens the heart of man,
oil to make his face shine,
and bread that sustains his heart.

Now what am I to do with that phrase in bold? Do I skip over it when reading it to a 6 and 9 year old? How does wine make a heart glad? Is this simply a human thought in the middle of a psalm of praise? What about Ephesian 5:18 (do not get drunk...)? Or the fine example of Jonadab and the Recabites? When you look at the full context of the Psalm, it's hard to imagine that this would slip in to a psalm of praise if it were not a "proper" thought. I'm inclined to believe that perhaps Wine too is a gift from God. Well, we know that to be the case literally in the time of Christ. So, yeah, I read it to my boys. They didn't ask any questions about it either. But it does make me wonder something else; why is it so many denominations speak out against the drinking of wine? To me, the Bible clearly speaks of moderation.