I recently did a Vermont style IPA with all pellet hops. After the primary fermentation I racked the beer and added some more pellet hops for another week. The taste after the primary fermentation was possibly a bit sweet but had the right bitterness and was cloudy as expected. After the additional dry hopping stage the beer became unbearably bitter! Does anyone know how this could have happened? Is it from the dust of the dry hop additions being left suspended in the beer? As from my understanding there should be no alpha acid extraction at 18c.