Every year, as the Super Bowl approaches, so too does the frequency of the "Bro-based" ads; talking animals, beautiful women, and beer, beer, beer fill our television screens. They pour on the promises, the jokes and the marketing gimmicks.
As I watch the variety of beer ads flash across my screen, I see mention of "noble hops," "triple hops brewed," "late hopping" and the characteristics of hop aroma or flavor. But what does that mean, really? What are they talking about? Are they just making stuff up?
Beer as we know it today wouldn't exist without hops. Hops provide balance to our beers and are nowadays the signature for many styles. They work as a natural preservative in beer, and when your beer is struck directly by sunlight for a time, they give off that distinct "skunked" flavor and stench.
To greatly simplify hops, brewing requires two things from them: alpha acids and beta acids. The main bittering agents in hops are alpha acid resins. These are insoluble in water and not very bitter until isomerized by boiling. The longer the boil, the greater percent of isomerization, and the more bitter a beer gets.
The beta acids are often called "essential oils," and are volatile and quickly evaporate. They provide the aroma and flavor to the beer.
I'd like to point out that each subheading of alpha and beta acid contains multiple distinct oils each, and they produce different effects on beer.
It is these oils, and how they manifest in beer, that are occasionally identified as "noble." Noble characteristics are found in hops with alpha acids and beta acids whose levels are similar.
Bittering/First Wort Hopping (FWH)
These additions are made at or near the beginning of the boil. Since they'll spend 45 to 90 minutes boiling, all aroma has evaporated. The only intent is to bring bitterness out into the beer. First Wort Hopping is the process of putting the hops into the pot and pouring the hot wort onto them prior to the boil.
Due to the volatility of beta acids, boiling for a shorter time is required to retain the characteristics brewers are looking for. Flavors are generally added when 10 to 30 minutes are left in the boil.
The aroma beta acids in hops are the most volatile, and aroma hops are used in the last 10 minutes of boil. Little if any bittering can occur at this point.
These are three different methods of the same thing: keeping the wort hot enough to extract beta acid oils without losing them to evaporation. The knockout method is simply adding hops when the heat is turned off the boiling kettle. The whirlpool method is used by adding hops to the brew kettle when the wort is pumped through in a fashion that gives the wort full contact with hops. The hopback method uses a separate container filled with hops that hot wort is pushed through.
This method is the addition of hops during the period of fermentation, usually when it is almost complete. Instead of using hot water, the alcohol now present in the beer allows the beta acids to break down and add aroma to the beer. Flavor is not added, but since scent is a large part of human taste, it seems to accentuate it.
Something I'd like to make clear is that the bittering, flavor and aroma processes happen throughout the process. The times I've reported are not set in stone, but estimates. Also … noble hops exist, triple hopped brewing is a marketing gimmick, and late hopping adds flavor and aroma.
Now drink smarter, not harder!