I know I mentioned this before and I don't want to derail the thread but in the past I have made some pilsnery and/or helles-like beers where I used something like Hallertau, Tettnanger, Saaz, etc. and the beer came out tasting a little flat and sort of dirty. It wasn't contaminated but it just wasn't right. Thinking back, it's very possible that the cause was old, mishandled, poorly-stored hops that just didn't have that fresh, vibrant character. Sometimes you open a bag of hops and the pellets look old and dry and are not aromatic. It's not ALARM BELLS "bad" but they're not fresh. When I open hops from YVH or HH, the pellets are super green, aromatic and usually the pellets are sticky and stuck together. That seems like a good indicator to me. I literally threw out brand new packages of Goldings, Hallertau and Tettnanger recently that I got from MoreBeer (their Artisan brand of hops) because their aroma was off and they just looked old and dry.