WHAT ARE HOPS?

Everyone loves hops. And it doesn't surprise me. Without it, there would be no such excellent drink like beer, or at least not in the way we know and understand it. But, in addition to knowing that it is an essential ingredient in brewing, do we really understand what effects it produces in our beer?

Hops, which Latin name is Humulus lupulus, belongs to the Cannabaceae family. This perennial climbing plant grows on other plants by twisting around them and can reach between three and six meters in height. Of the four essential ingredients for brewing beer (malt, water, yeast, and hops), hops are the one that aromatizes it and adds bitterness. In addition, it helps to preserve it due to its antibacterial action, contributes to the formation and retention of foam, and facilitates filtering thanks to the reaction of polyphenols with malt proteins that makes them insoluble. But behind hops there is so much more.

TALKING ABOUT HOPS WITH SCOTT JANISH, AUTHOR OF “THE NEW IPA”

To delve into the wonderful world of hops, and more specifically, the scientific side of hops and the factors that contribute to enhancing the aroma and flavor in beers high in hops, we have contacted Scott Janish, author of the book reference "The New IPA: Scientific Guide to Hop Aroma and Flavor." After the great success in its English version, it is just about to be released in Spain by Libros de Guarda; the first publishing house specialized in beer books in Spanish.

Scott, who defines himself as a home brewer and beer blogger, is also the co-founder of Sapwood Cellars (Columbia, Maryland), a brewery specializing in barrel-aged mixed fermentation beers and fresh, hoppy IPAs. He discovered his passion for learning, researching, and putting what he learned into practice at the end of January 2016. In the aftermath of a snowstorm, he was trapped at home and studied extraction during dry-hopping. From then on, he realized that he could spend countless hours surfing the internet and reading the work of beer researchers worldwide.

Based on multiple experiments, more than 1,000 academic studies, laboratory analysis, conversations with researchers, and interviews with recognized and award-winning commercial brewers, Scott has created an advanced guide composed of fifteen chapters that, as he recognizes, requires from the readers some prior knowledge of both the terminology and the process. A deep and systematic look that is sure to delight any brewer thirsty for learning and improving their recipes and will satisfy the curiosity of all those interested in delving into the mysteries of hop aroma and flavor.

From C R A F T E D, I want to thank Scott for enlightening us with his magnificent answers to the different questions made for this article, as well as Aitor Labrador, journalist, and co-founder of Libros de Guarda, for having introduced us. Much success to both of you with the book's launch in Spain; I am looking forward to getting my hands on a copy!

Ø: There are three major components of hops that reside in the lupulin gland of the hop. Could you explain briefly which of these components affect to the bitterness and which of them enhance the flavor and aroma in the beer?

Scott: The three major components that make up the hop oils are 1) Hydrocarbons (biggest section of the oils) 2) Oxygen Containing Compounds (like monoterpene alcohols) and 3) Sulfur Compounds (Thiols). 

The Hydrocarbons are the most volatile part of the hop and are non-polar. This generally means they will volatilize quicker than the other compounds, especially when added to the kettle where heat will drive them off. They do, however, reside in higher amounts in hazy IPAs, where the haze itself helps to retain these compounds, which are generally woody, herbal, and resinous in flavor/aroma. 

The oxygen-containing compounds make up the second-biggest chunk of the hop oils and are more polar than hydrocarbons. Some of these compounds (like monoterpene alcohols like linalool and beta-citronellol) are often looked at as markers for "hoppiness" in beers when tested. These fruity compounds help build hop complexity when in beers and can work together synergistically with sulfur compounds to increase overall flavor and aroma. 

The sulfur-containing compounds, particularly the thiols 3MH and 4MMP, are less than 1% of a hops total oils, but can still play a significant role in flavor due to their potency. Hop-derived thiols have such low thresholds that pushing them into the final beer can help to play a role in some of the hazy IPA typical flavors (especially 4MMP which is likely in beers in higher rates than 3MH). 

Ø: What are the benefits of brewing with hop pellet blends?

Scott: Hop blends, which often contain hops from the same variety, but from different lots, can help with a more consistent hop variety flavor. This consistency is due to the fact that you can look at the oils of multiple lots and use them to determine what type of blend is needed to hit a target profile for the hop that brewers expect. Hop blends can help prevent getting hops from lots of lower quality because they are blended with hops of higher quality from other lots. The downside of hop blends is that they also can prevent you from getting hops that really shine. When a brewery reaches a certain size, they are allowed to select their hops from individual lots (no blends) which can give them an advantage by choosing hops that really shine and stand out from a blended hop of the same variety! 

Ø: One of the common practices for keeping the more volatile hop compounds in the wort is late hopping. Could you explain, in your experience, how the temperature and duration of the whirlpool can affect the extraction of hop oils and alter the sensory experience?

Scott: There is research that suggests that lower the temperature of the whirlpool can help to retain more hops oils than when done at warmer temperatures. This retention is likely due to the fact the warmer the wort is, the more the heat is driving off volatile hop compounds from the wort. I often shoot for a whirlpool temperature around 82 degrees celsius and whirlpool for approximately 30 minutes in order to increase the retention of the hop's fruity oils. The extraction or retention can also increase when using hops that are higher in what's now called "survivable" compounds. Hops higher in these compounds are varieties like Idaho 7, Mosaic, Bravo, Centennial, and Millenium. 

Ø: We all know that hops are best as fresh as possible. Could you describe what happens to hops when they age? Do aged hops impact in any way when using them in brewing modern IPAs?

Scott: When it comes to dry-hopping, hops that have too much age can have a negative impact on flavor and aroma due to a developed cheesy or dull aroma. However, some of these cheesy-like compounds are precursors to fruity esters that can develop during fermentation, so using slightly older hops in the whirlpool might actually be good for creating complexity in flavors. Particularly, fatty acids (oxidative-degradation of hop bitter acids) can be esterified into fruity ethyl esters like 2MIB through biotransformation. Hop fatty acids, resulting from aging hops, also work synergistically increasing the fruity perception of monoterpene-alcohols, which is another reason to potentially include a portion of slightly aged hops in the whirlpool. 

Ø: Hops also play a role in foam quality and retention. Said that, which varieties would you recommend for obtaining a good creamy head of foam?

Scott: Although beer foam is likely the result of multiple factors like foam-positive proteins in malt, α-acids, iso-α-acids from hot-side hops, metal cations, alcohol concentration, and the reduction of lipids, there is some research suggesting that certain hop varieties are better at foam retention than others. In a test of five different hop varieties, a paper found that there was a reduction in foam stability with Bravo, Centennial, and Cascade, but an increase in foam stability with Eureka and Apollo. One possible reason for the results is that Eureka and Apollo had the lowest amount of fatty acids which are foam negative. Perhaps the paper's results add another reason to use these hops with higher fatty acids in the kettle where they can help build in complexity while not hampering foam retention during a dry-hop. 

Ø: And finally: your book includes some tips from commercial breweries, like for example the well known hazy and hoppy masters from Other Half Brewing. Are there any specific details that surprised you in terms of their brewing methods?

Scott: It's great that brewers, like at Other Half, are open to sharing their processes to help us all learn and think harder about our own techniques and recipes. What surprises me is that every brewery approaches hoppy beers slightly differently. Sometimes because of their equipment and size, whether or not they have a centrifuge (which can speed up the process and potentially allow for even higher dry-hopping rates due to the stripping of hydrocarbons prior to packaging), and how they attack hop-creep. There isn't one perfect way to make hoppy beer and talking to some of the best breweries in the United States showed this!