Hops, Part 1: How Hops are Used in Brewing Beer

Brewer's Blog #7

  • February 2nd, 2017
  • By Stephen Rich

In the 5000+ year history of beer, hops are a relative newcomer to the brewer’s toolkit. Hops were first commercially used in England only 600 years ago, in 1412, and were not widely used until the Bavarian Purity Law of 1516 (the Reinheitsgebot) decreed that beer must include hops. And it was not until 1710 when the English Government banned the use of non-hop bittering agents in beer.

If you dig a bit, you’ll see that hops have a convoluted history that involves agriculture, tax regulation, quality control, and market preference factors that have contributed their now stronghold in a beer’s makeup. For the modern brewer, hops primarily provide bitterness, aroma, flavour, and preservative properties to beer. There are entire text books written on hops – today we’re going to review how hops are used in brewing. In another blog, we’ll look more at what a hop is, how they are cultivated, and how terroir contributes to the finished beer.

Brewing Beer with Hops

Let’s start by separating the production of beer into two halves; hot side, and cold side. The hot side is brewing. This is where we mash grains, extract the sugary wort, boil it, then whirlpool out any solids. The cold side is where fermentation, ageing, filtration and packaging happens.

Hot Side of Hops: Brewing

Hops are almost always (99.99%) used on the hot side of brewing, primarily in the kettle when boiling the wort. Hops are generally used by the brewer in dried or pelletized form, and are added to the boil to contribute bitterness and aroma to the beer. There are two components to a hop that get extracted in the boil — alpha acids, which contribute bitterness, and essential oils, which contribute aroma. The timing of when you add your hops will have a significant effect on how the extraction takes place.

The longer your hops are in the boil, the more alpha acids are absorbed by the wort, and thus, the more bitterness you will get from a specific amount of hops. At the same time, the longer your hops are in the boil, the more essential oils you will lose. The essential oils in hops are very volatile. The wort will absorb them quickly at high temperatures, but boiling will drive off those aromatic compounds. Therefore, the less amount of time a hop is in the boil, the less bitterness you will get, but more aroma. The longer a hop is in the boil, the more bitterness you will get, and the less aroma.

Generally, brewers will use a combination of hop additions to achieve the balance they are looking for. Let’s imagine you are boiling your wort for 60 minutes. To achieve some bitterness, you may add hops right away so they boil for the full 60 minutes and extract as much bitterness as possible. Then you may add hops again with 20 or 10 minutes left to add a balance of both bitterness and aroma. This is what we do with Absent Landlord to achieve a delicate balance of bitterness and aroma.

Finally on the hot side, the whirlpool is used increasingly to charge beers with juicy hop flavour. In the whirlpool, the wort and hops are spun at high speeds. This happens just off the boil, so brewers are often adding large swaths of hops to the whirlpool to add significant aroma, without any or much bitterness. As an example, Doc Perdue’s Bobcat has a significant charge of hops in the whirlpool, and only minimal in the boil.

Cold Side of Hops: Fermentation, Ageing, Filtration & Packaging

In a modern craft brewery, especially in North America, the majority of hop use may happen on the cold side. After fermentation is complete, the sugary wort is now alcoholic beer. This provides the brewer with an opportunity to add even more raw hop aroma and flavour to their beer.

During the boil, brewers are trying to coax out hop aromas with heat. In an ageing tank, with the help of alcohol and time, you can extract those aromas more efficiently. Imagine making a vanilla extract at home. If you steeped vanilla beans in near boiling water, you would have a mildly vanilla flavoured water. But, if you soaked them in vodka for a week, you’d have a potent vanilla extract. This is what happens in the ageing tank – a process known as Dry Hopping.

When fermentation is complete, brewers will reduce the temperature of the beer — which will be specific for every brewery and every recipe. Then they will add dried or pelletized hops to the tank, or transfer the beer to a new tank with hops already added to it. The finished beer is now mixing with the hops, extracting their essential oils, but not the alpha acids — that requires heat. This is the advantage of dry hopping — all aroma, no bitterness.

The dry hopping process occurs in conjunction with ageing — or maturation — for anywhere from 5 to 14 days, or in some instances more. Doc Perdue’s Bobcat gets significant dry hopping, and matures for 14 days on those hops. After these two weeks, the hops are removed from the beer either by gravity, separation, or filtration — then the fresh hoppy beer is packaged and ready to drink.

Enjoy Your Hoppy Beers

While this is not a consideration when brewing beer with hops, it is extremely important for beer lovers to consider. Drink your hoppy beer fresh! Now that the brewer has charged your favourite beer with all these amazing aromatic hop compounds, the beer is at its optimal point the moment when it is packaged. Every day from that moment, those volatile essential oils break down and aromas fade, and the characteristics that the brewer intended reduce.

For best results, buy hoppy beers cold when possible, keep them in your fridge at all times, and enjoy them within three months of the packaging date – optimally, they would be consumed within two months or less. Trust me, there is nothing better than the piney and citrus hop flavour brimming from Doc Perdue’s Bobcat the day we put it in a can. Ohhhhh yeah.