Beer wouldnt be considered strong drink, particularly not the light beers. Most of the scriptures are against drunkardness, not because drink is wrong of itself, but because of what it leads to if taken in excess - violence, fighting, sexual immorality etc. In Eph 5:18 I suppose you missed reading the bit where it says "wherein is excess", meaning, the kind of drunkeness which leads to riotous or excessive living. In other words, getting drunk or "plastered", for the sole purpose of getting drunk, as many do today. It doesn't seem to prohibit getting drunk for accidentally drinking too much or drinking at all, on occasion. But it only prohibits the use of alcohol for the purpose of getting drunk which would lead to riotous living and a substitute for the Holy Spirit in your life.