You can absolutely dry hop cold beer! In fact, there are some benefits to dry hopping at cooler temperatures. One of the advantages is that it reduces the contact time needed for the dry hop.
According to an article I came across from BSG called “Reevaluating Dry Hop Techniques,” dry hopping at cooler temperatures (specifically 34-39°F or 1-4°C) actually resulted in a faster extraction of linalool. Linalool is one of the key compounds responsible for the hop aroma in beer. The study found that maximum extraction of linalool occurred after just two days of cold dry hopping.
This finding is quite interesting because traditionally, dry hopping is done at warmer temperatures, usually around fermentation temperature or slightly above. The idea behind this is that the warmer temperatures help facilitate the extraction of hop oils and aromas from the hops. However, this study suggests that cold dry hopping can be just as effective, if not more so, in terms of extracting desirable hop compounds.
Personally, I have tried dry hopping cold beer and have had positive results. I found that the hop aroma was still very pronounced and vibrant, even though I did not leave the hops in contact with the beer for as long as I typically would with warm dry hopping. This is great news for brewers who may be looking to speed up their dry hopping process or who may not have the luxury of leaving the beer at warm temperatures for an extended period of time.
To summarize, yes, you can dry hop cold beer and it can yield excellent results. The colder temperatures can actually reduce the contact time needed for the dry hop, resulting in faster extraction of hop aromas. So if you’re looking for a quicker and potentially more efficient way to dry hop, give cold dry hopping a try!