LOVE THEM or hate them, hoppy beers are all the rage these days. The popularity of the IPA (India Pale Ale) style exploded in the late 2000s as brewers uncovered a nearly insatiable demand from self-proclaimed “hop heads” for more varieties and blends of hops. But what exactly are hops, why are they used, and why do beer drinkers who generally dislike bitterness still owe them respect?

The hops used in today’s beers are the female flowers of the Humulus lupulus species. Although typically added as a flavoring agent today, hops also served as a preservative for many centuries. All beer is brewed with hops of some sort, though the style and desired final flavor profile dictate the quantity and variety used.

During the brewing process, the liquid solution of water and malted grain is brought to a boil. The result is called “wort,” and hops are added to it in two stages: flavoring hops first, and aroma hops at the end. Boiling breaks down the hop’s alpha acids (which are directly responsible for imparting bitterness) and allows them to be absorbed into the beer. Bitterness is controlled by the boil time (a longer boil yields more bitterness) and the concentration of alpha acids in each selected hop. Aroma hops are deliberately added towards the end of the boil to ensure some of the flower’s oils remain intact. This contributes a pungent, hoppy aroma to the brew. Adding fresh hops during the fermentation stage, a process known as “dry hopping,” increases the hoppy intensity across the board and is quite popular today.

Measuring bitterness

The total amount of alpha acids assimilated into the liquid directly correlates to its final bitterness, which is measured on the International Bittering Unit (IBU) scale. The IBU system dates to 1968, when American and European brewers joined forces to define a scale running from 1 to 100, with the intensity of a beer’s bitterness content increasing as the numbers rise. A higher number doesn’t always indicate a greater perceived bitterness, however, since the amount of malted grain used to balance out this bitterness contributes equally to the overall flavor profile. For example, Stone’s Imperial Russian Stout weighs in at 55 IBUs, yet it tastes far less bitter than their Pale Ale (41 IBUs) due to the tremendous amount of malt present in the stout.

Here’s a quick reference of some styles and their typical IBU range:

Style IBUs
American Light Lager 5 to 15
Hefeweizen 10 to 20
English Bitter / ESB 25 to 45
Porter 30 to 50
IPA 40 to 75
Imperial Stout 50 to 80
American Barleywine 50 to 100+
Imperial / Double IPA 60 to 100+

As you can see, hops play a pivotal role in all styles of beer, even those which don’t taste particularly bitter. The difference between Single IPAs and Double IPAs is a perfect example: Single IPAs are generally brewed with very little malt, while Double IPAs typically exhibit a hearty malt backbone to counterbalance the increased hop intensity. The resulting hoppy bitterness found in most Single IPAs is rather polarizing and turns some drinkers away from IPAs in general, not realizing that they might actually love a well-crafted DIPA. Single IPAs at a lower IBU can taste significantly more bitter than even 100+ IBU DIPAs.

Know your hops

Apart from IBU, the single most important factor in determining characteristics of both Single and Double IPAs is the type of hop(s) used. The West Coast style tends to favor more floral, piney hops with less malt and a higher overall bitterness, while IPAs in the East Coast style place a larger emphasis on the underlying malt base and tend to use juicy, fruity hops. Brewers from all parts of the country now brew ales of each style, making these terms somewhat of an anachronism, but knowing this distinction helps accurately describe what you’re drinking.

There are more than 115 varieties of hops commercially available today, with new hybrid strains being introduced every year, and each imparts its own distinctive flavor profile. Tastes and aromas are extracted depending on when (and for how long) in the brewing process the hops are added. Using a mix of different hops is common in today’s beers, in order to take advantage of the best qualities of each.

A few well-funded brewers have embarked on single-hop IPA experiments in recent years, using only one type of hop for the entire brewing process, and then repeating the recipe a number of times with a different hop each time. Mikkeller, Hermitage, and Hopworks all recently participated in this experiment, allowing beer drinkers a fun method of determining which strain of hop they most enjoy. The biggest downside to this undertaking is that, like all beers with a hop-forward profile, these single-hop IPAs need to be consumed within 90 days (but preferably 30!) of brewing to properly appreciate each hop’s flavor profile. Hoppy beers fade quickly; always drink them as soon as possible!

The many dozens of hop varieties are most easily categorized as exhibiting one of these general characteristics: piney, floral, or juicy. Brewers typically use combinations of hops to bring a few of these qualities together.

Piney hops

The classic piney hop profile is what many associate with IPAs, and hoppy beers in general. Chinook and Simcoe are widely used to impart the dry, resinous, grassy, woody sensations typically attributed to piney hops. Both possess a relatively high concentration of alpha acids (12% to 14%), which generally yields high levels of bitterness.

Pine is a primary component of most IPAs brewed in the West Coast style. Good examples of a piney IPA are Alpine’s Duet, Dogfish Head’s 60 Minute IPA, and New Belgium’s Rampant Imperial IPA.

Review: Rampant Imperial IPA, New Belgium Brewing
New Belgium’s Rampant IPA (85 IBUs) sports a “best before 7/7/13” date, which is more than three months in the future from when mine was opened. All commercial IPAs should post a freshness date! Gorgeous pour: slightly hazy gold with copious amounts of white head. Sticky lace, stubborn retention. Fresh piney hop aroma, mildly spiced, creamy malt to round out the nose. But the malt is surprisingly absent on the palate, replaced instead by fresh, piney hops and resin. Leaves a strong bite of bitterness at the end. Label claims peachy fruits, yet I didn’t detect any in my bottle. This is a hop bomb start to finish; certainly in the West Coast style, and more of an imperial Single IPA than a true DIPA.

Floral hops

Floral hops really send your olfactory senses into a frenzy. Nugget, Amarillo, and Ella all provide these earthy, flowery, perfume-y qualities, while Mosaic straddles the line between floral and juicy. Floral characteristics tend to be more powerful in a beer’s aroma than on the palate, though there are certainly exceptions.

For a floral experience, check out Tröegs’ Nugget Nectar, Russian River’s Pliny the Elder, or Stone’s “Enjoy By” IPA series.

Review: “Enjoy By” series, Stone
Stone’s “Enjoy By” series of DIPAs boldly educates consumers about the necessity for freshness in IPAs. With 7 releases under their belt since fall 2012, Stone targets only a handful of markets for each release rather than their entire distribution network, to ensure you’re drinking the freshest hops possible. I drank the Enjoy By 12/21/2012 batch over Thanksgiving to discover a pungent aroma of fresh, flowery hops from its 88 IBUs. Coats the palate smoothly as its earthy, floral hop character and soft malt presence make their stand. Ends with a hint of booze and light bitterness in the back of my throat. The 5/17/2013 batch was the first to introduce a noticeable fruity character to the blend, which subsequently makes it this (admittedly biased) reviewer’s favorite of their releases.

Juicy hops

IPAs with a juicy hop profile trick your mind into thinking freshly squeezed fruit juice was added to the recipe. These tend to be the most approachable, as their bitterness kick is typically minimized to make way for the tropical fruit overtones. Lemon citrus, orange, grapefruit, mango, apricot, and pineapple are common characteristics from these hops. The most widely recognized is Citra, a hybrid which was first bred in 2007 and quickly became a favorite of brewers and drinkers alike. Centennial and Nelson Sauvin also provide a juicy experience.

See for yourself with one of these beers: Three Floyds’ Zombie Dust, Sierra Nevada’s Torpedo Extra IPA, or Ithaca’s Flower Power.

Review: Zombie Dust, Three Floyds
Zombie Dust (60 IBUs) is an American Pale Ale brewed exclusively with Citra hops. Its unrelenting aroma is bursting at the seams with fresh, juicy hops. Orange, pineapple, citrus, and grapefruit all join together in the nose. Taste starts off with bready malts before the hops kick into full gear again, imparting juicy tropical fruits amidst the creamy malt. Bitterness is kept in check throughout by this grain base. Mildly sweet through the middle, fading to finish dry and softly bitter. A refreshing beer with high drinkability and wide appeal. Reason enough to make friends with someone in the Three Floyds distribution radius.