I do it in primary, and normally for 1 week.
This brings up something that I have been wondering about for a little bit now. Most experienced brewers say something along the lines of, "I don't rack to a secondary unless I want to add something after fermentation, like dry hopping." This is usually said when discussing the subject of "should I rack to a secondary." As most of us know, ten years ago racking to a secondary was just how homebrewers did things because that is how the pros do it. Today, a lot of homebrewers simply don't rack to a secondary because it isn't really necessary.
I've heard Jamil talk about this on Brew Strong, and he talked about how pro brewers like to get their beer off of the yeast because large amounts of yeast is heavily compacted at the bottom of their giant fermenters, and that can produce a lot of heat and more chances of off flavors. As homebrewers, however, we don't have that heavy compaction of large amounts of yeast in the bottom of our carboys or plastic buckets. And so, the philosophy on racking to a secondary has recently changed, and many no longer rack to a secondary... except when ingredients are added after the fermentation.
So, this brings me to my question. Why rack to a secondary at all, even for dry hopping or adding other post fermentation ingredients? Personally, and as an inexperienced homebrewer, I haven't seen any reason to yet, so I haven't bothered, even when dry hopping. I have not tasted two dry hopped beers made exactly the same, but with one that was racked to a secondary, and one that wasn't.
Sorry to derail the conversation; this is just something that has been on my mind lately. Any thoughts on why one shouldn't just dry hop in the primary?