Hops are one of the 4 essential ingredients in beer. They have many important functions in brewing and have a very big effect on the character of a beer. But what are they, and how are they used? Read on to find out!
What Are Hops?
Hops are the dried flower cones of the Humulus Lupulus vine. They look like small green pine cones, and have a papery texture. They contain tiny glands that contain a yellow resin called lupulin. Lupilin is made up of a number of essential oils and acids that are released when the hops are added to beer. The acids in lupulin also have some slight antibiotic properties and help protect the beer from infection. Hops are mainly used to make a beer bitter. This helps to counteract the sweetness of the sugars from the malt. See this article for more information about malt.
How Are Hops Used in Brewing?
Hops are usually added to the boiling wort. For some background information on the brewing process check out this article on how beer is made. Hops impart different characteristics depending on how long they are boiled. If hops are added at the beginning of the boil they impart a bitter flavour to the beer. Hops contain compounds called alpha acids that change structure (isomerise) when exposed to the heat of the boil. The longer the hops are boiled the more alpha acids that will isomerise and the more bitter the beer will become. Some hop varieties of hops, such as Chinook, have a high concentration of alpha acids and can make beer very bitter.
Other varieties of hops, such as Hallertau, have lower alpha acid content but higher quantities of essential oils. These essential oils, such as humulene and myrcene, provide interesting resinous flavours and aromas to the beer. Hop aromas can be described as earthy, piney, citrusy, floral, and spicy. They are usually added later in the boil so that the essential oils don’t evaporate and disappear from the brew! Flavour and aroma hops can still be used for bittering, but a greater quantity is needed to get enough alpha acids. Likewise, many bittering hops contain plenty of essential oils and can be used for flavour and aroma characteristics. Sometimes hops are added directly to the fermenter in a process known as dry hopping. Dry hopping provides mostly aroma character as it preserves the humulene and myrcene in the beer.
As discussed above, hops come in two main varieties – high alpha acid and low alpha acid. High alpha hops like Warrior, Chinook, Magnum and Simcoe are used mostly for bitterness. They are used in beers where very high bitterness is desired, such as American style India Pale Ales. Low alpha acid hops such as Hallertau, Saaz, Cascade and Fuggle are used mostly for aroma and flavour characteristics. Certain European varieties of low alpha hops are called Noble Hops for their refined, mellow character. Noble hops include German Hallertau and Czech Saaz. Saaz is the variety responsible the hop character of the Pilsener style.
Hops are available to home brewers in two main forms – as pellets and as whole hop cones. Pellets are made from ground-up and extruded hop cones, and are very convenient to measure and store. Whole hop cones can be quite bulky, and tend not to store as well as pellets. Hops should always be stored in an airtight container away from heat and sunlight to prevent oxidation and UV damage. Hops can take on a catty, skunk-like or cheesy flavour if not properly stored. Not a good quality to have in a beer!
Hops can really bring out the character in a brew, and can certainly add a number of unique flavours and aromas. From the in-your-face bitterness and citrus character of American ales to the more refined floral character of European lagers, hops add plenty of interesting depth to any beer.