Dear Mr. Wizard,
Over the years I have read a number of articles on dry-hopping and hopback use. As I understand it, dry- hopping should not be done in the primary fermenter because the “scrubbing action” of the yeast activity will diminish the desired results of dry-hopping. At the same time, most articles on hopbacks say the unit should process the hot wort directly from the boiling kettle so that the high heat helps to sanitize the hops and to extract the hop oils. But now the wort is in the primary (cooled, of course) and subject to that same “scrubbing action” mentioned earlier! I would appreciate any information you might provide to clear up these issues.
Yuba City, California
Mr. Wizard replies: Most brewing techniques are touted by a long list of advantages. Dry-hopping, which means adding compressed hop cones or hop pellets to beer or fermenting beer, can be “sold” by its ability to contribute a nice, fresh hop aroma. Why put hops in the kettle or use a hopback when you can add them straight to the fermenter?
Hopback advocates almost always mention the bonus of having the hops and the hopback sanitized in the process. This casts a cloud over the method of dry-hopping, because it implies that hops are covered in bacteria and require sanitization (an argument that is not well supported). Dry-hoppers feel pretty confident about the method — after all, dry-hopping would not be popular if it routinely produced contaminated beer. Plus, dry-hoppers avoid the “scrubbing” action of primary fermentation.
When reading the hype surrounding these methods, it is hard to get a feel for the salient features of each method. When I want a really hoppy beer with a fresh hop oil aroma, I prefer dry-hopping. The aroma of dry-hopped beer is often described as grassy and frequently has the distinct aroma of myrcene (a particularly aromatic hop oil). Hopping rates vary depending on the hop variety and oil content, but 1/4 to 1/2 to ounce of hops per gallon of beer is a pretty normal range for dry-hopping. When I dry-hop, I do it after primary fermentation is complete and before moving the beer to a cool location for aging.
But I personally prefer adding hops to hot wort, usually in the kettle at the end of the boil for most beer styles, because the grassy and oily aromas are less pronounced. The little brewery up Highway 99 from you is well known for the hoppy aroma of its brews, especially its Pale Ale. Sierra Nevada uses a generous late-hop addition in all of its standard beers and only dry-hops the Celebration and Bigfoot. Hops added late in the boil or to a hopback can certainly produce a very hoppy beer, but the hop aroma is less “raw” in comparison to dry-hopped beers. Hopping rates for late-hop additions and hop-back additions vary, but 1/4 to 1/2 ounce per gallon will produce beers with pronounced hop aroma.
By the way, some commercial brewers use in-line hopping devices that are similar to the typical homebrew hopback. Many commercial hopbacks are vented — they’re like big strainers placed between the brew kettle and the wort cooler — but the in-line devices aren’t vented. This means the grassy and oily aromas are extracted from the hops but do not escape from the wort. This method produces an aroma more similar to a dry-hopped beer. The purported advantages are that the hops are sanitized, more oils are extracted because the wort is hot and the hops do not have to be fished from the fermenter after they are spent. But the aroma is still “scrubbed” during fermentation.
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