Apart from the standard wines - Trier is in a wine-growing area - and beers Trier - Löwenbräu, Cologne - often Gaffel Kölsch, Bitburg - Bitburger, one should definitely try Viez or Viez/Limo. Viez is an apple wine, which is often served with a splash of lemonade. But be carefull: there is sweet and sour Viez don't order a big glass, if you are only testing.
