What is Dry Hopping?
Hops are the female flowers (also called seed cones or strobiles) of the hop plant, Humulus lupulus. They are used primarily as a flavoring and stability agent in beer, to which they impart a bitter, tangy flavor, though hops are also used for various purposes in other beverages and herbal medicine.
Hops are usually dried in an oast house before they are used in the brewing process. Undried or “wet” hops are sometimes (since ca.1990) used. The wort (sugar-rich liquid produced from malt) is boiled with hops before it is cooled down and yeast is added, to start fermentation.
Hop resins are composed of two main acids: alpha and beta acids. Alpha acids have a mild antibiotic/bacteriostatic effect against Gram-positive bacteria, and favor the exclusive activity of brewing yeast in the fermentation of beer. Alpha acids such as isohumulone are responsible for the bitter flavor in the beer.
Beta acids do not isomerize during the boil of wort, and have a negligible effect on beer taste. Instead, they contribute to beer’s aroma, and high beta acid hop varieties are often added at the end of the wort boil for aroma. Beta acids may oxidize into compounds that can give beer off-flavors of rotten vegetables or cooked corn.
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. Nowadays, dry hopping refers to any hop addition after the wort has been cooled.
Dry Hopping Techniques
Hops play a number of roles in the brewing process. Depending on when they are added, they contribute bitterness, flavor, aroma or something of all three. The bitterness comes from alpha acids contained in hops, while flavor and aroma come mostly from volatile oils.
The term volatile refers to the fact that the oils boil out of the wort relatively quickly — most within 15-20 minutes. This is why brewers normally add flavor and aroma hops closer to the end of the boil. For maximum flavor and aroma, and to preserve as much of the volatile oils as possible, some brewers practice dry hopping.
Read more here: Dry Hopping: Techniques – Brew Your Own
Dry Hopping for Great Aroma
Adding hops later in the process preserves the flavor and aroma from the hops’ oils. These are distinct from the alpha acids that give the beer its bitterness. The oils add no bitterness, just flavor and aroma. During the boiling process, nearly all of the hop oils evaporate; the longer the boil time the more oils are lost.
The hops put in at the beginning of the boil for bittering lose almost all of their oils. Those added near the end of the boil don’t lose as much oil but still lose quite a bit. And the heat of the boil induces chemical changes in the oils, so even those that are left lack the aroma of fresh hops.
So if we want to add hops to impart a fresh hop aroma to the beer, when is the best time to do it? Traditionally, dry hopping was done in the serving cask. A charge of fresh hops would be added to the cask right before the bung was hammered in. If you keg your beer, you can add the hops to the keg.
This gives the beer the best and freshest aroma. But what if you bottle? It makes sense to take a step backward in the process and add the hops to the fermenter. But there is a right time and a wrong time to do it.
Read more here: Dry Hopping for Great Aroma – Brew Your Own
Enhanced Hops Aroma
Dry hopping involves adding hops to the fermenter or keg after fermentation. Dry hops add no bitterness to the beer, but the technique does add fragile aromatic oils that are normally lost in the boiling process. Dry hops are allowed to soak in the finished beer for anywhere from several days to several weeks. The result is a burst of hoppy aroma.
Commercial craft brewers use dry hopping to enhance their beer including Anchor Liberty, Samuel Adams Pale Ale and Sierra Nevada celebration. Many drinkers prefer the distinctly floral hop aroma that dry hopping adds. On the con side, some drinkers perceive a “grassy” or “oily” flavor from dry hopping. The technique is appropriate for brewing beer styles with high hop rates such as IPAs, Pale Ales, some Stouts and California Common (Steam) beer.
Read more here: Dry Hopping: Enhanced Hops Aroma | Home Brewing Beer Blog by …
Beer Geek Nation Homebrew 101: Dry Hopping
Home Brew Manual with Dry Pellets
As you would expect from home brewing, there are many ways of adding the hops.
Although some brewers put them straight into the primary fermenter, it’s generally agreed that it’s best to wait for the primary fermentation to finish. Otherwise, much of the benefit will be lost for reasons described above.
It’s common for brewers using a secondary fermenter to add the hops when they transfer the beer. However, dry hopping in the primary is also possible.
For my batch of mild I wanted to take the beer off the trub. It’s a relatively strong beer and I’m planning to leave it a while before bottling. I took the opportunity to add the dry hops at this point…
Read more here: Dry Hopping – Home Brew Manual