My last batch (extract IPA) had what I would consider a clear oxidized taste (wet cardboard). Aside from the fact that it might have oxidized from the normal sources (i.e. splashing the wort at a high temp), are there any other causes? I've read that use of old or stale steeping grains could cause this as well. Unfortunately, I live in an area where there are no LBHS (Japan) and must "stretch" out what I have on hand. What I steeped in the recipe was probably several months old, though not milled prior to brew day. Not much info out there on exactly how to tell if steeping grains are beyond their shelf life.