Okay, so I am currently working on my first batch that I Intend to Dry hop. I am getting a ton of mixed messages and want to see what the majority thinks. So I have finally come to the conclusion that for a small 5 gal batch, racking to a secondary is more risk than just leaving it in primary for the entire fermenting period. According to John Palmer, bigger breweries just rack to secondary vessels because the amount of sediment is MUCH greater than what we are dealing with and can cause off flavors. The only time we should rack is with fruit additions, or other fermentables and or if we intend to age. Well I'm finding a lot of brewers telling me they ONLY transfer to secondary if they are dry hopping or making additions. Then I have others telling me you can just dry hop in primary a week or so before bottling. Everyone is contradicting each other and just when i think I'm solid on what I believe, someone changes my mind. Let me know what you guys think!
In my opinion a "secondary" should be viewed as a tool. A potentially useful tool, but best used by someone who really has a grip of their brewing process and using it for a very specific purpose. I agree with Palmer, dont chase what the big brewers do, they have different issues then homebrewers. I would definitely suggest dry hopping in your primary vessel but AFTER FERMENTATION IS COMPLETE (I did when I bottled), fermentation will drive off volatile components of the hops. There is a lot of contradictory information out there, Take it all with a grain of salt most things "work" and some work well. As you gain experience you will start to see what works for you!
Good luck and keep us posted!
It's not contradictory so much as it's all valid. :)
To answer the titular question: yes, you can dry-hop in primary. Long-term aging is really the only reason to rack to secondary. Dry-hopping, fruit additions, &c. can all happen in primary just fine. Anything that happens w/in 6 months can happen in one vessel (primary) or two (primary and secondary).