What Is dry hopping?
The term dry hopping originated centuries ago with British brewers and was used to refer to adding hops to the cask shortly before it was shipped off to the customer. In fact, 1/2-ounce hop plugs were specifically developed by British hop producers to be a convenient way to add whole hops to a keg or cask. Nowadays, dry hopping refers to any hop addition after the wort has been cooled. These additions can be done in the primary fermenter, in the secondary or by adding hops directly to a keg. I have even heard of one homebrewer attempting to add one or two hop petals to each bottle of a bottle-conditioned batch! (It didn’t work though.)
When to dry hop
Once you’ve decided what hops you’re going to use, you need to decide when to add them. The choices are in the primary fermenter, in the secondary fermenter, or in the keg.
Dry hopping in the primary fermenter will work, and is favored by some brewers, but conventional wisdom teaches that the primary might not be optimal. The problem lies in the bubbling of the CO2 and the agitation of the wort during primary fermentation. This bubbling and agitation takes some of the hop aroma out of the beer just like boiling would. This, of course, may defeat the purpose of dry hopping, although some of the hop essence will subsist. If you choose to dry-hop in the primary fermenter, you may want to add more hops than you would for dry hopping in the secondary or keg.
The secondary fermenter is generally considered the best place for dry hopping for a couple of reasons. First, the beer has already mostly fermented so, as mentioned above, the alcohol and low pH helps to ward off any bacteria on the un-sanitized hops. Second, the vigorous CO2 activity of the primary is finished, so the aroma of the hops won’t be scrubbed out of the beer.
There is, however, one potential difficulty with dry hopping in the secondary. Many brewers use glass carboys with narrow necks as their secondary fermenters. Getting the hops into, and then back out of, the slender opening can be an exercise in frustration. This is especially true if you like to keep the hops in a bag, making it easy to separate them from the beer. My recommendation is to use a bucket with a large opening rather than a carboy, or to forget about putting the hops in a bag and just dump them in. You can then separate the hops from the beer when racking to your bottling bucket or keg.
