Brewing 101: Hops

What are Hops?

Hops are the flowers, or “cones,” of a plant called Humulus lupulus that are used to 1) provide bitterness and 2) contribute to the flavor and aroma of the beer.

Hops are grown all over the world. You’ll find hops broken down into a few main classifications:

  • Old World
    • Noble (German/Czech)
    • British
  • New World
    • American
    • Australian
    • New Zealand

Characteristics of Hops

Hop Bitterness

Many different chemical compounds in hops serve various functions in beer making. One common term one will hear regarding hops is “alpha acids”. Alpha acids are compounds that will change their structure (“isomerize”) when heated to produce other compounds which are perceived as bitter.

Hop Flavor and Aroma

Hop flavor is the overall combination of hop bitterness, mouthfeel, and aroma.

Hop aroma can be broken down into 7 main categories:

  • Floral
    • Rose, geranium, lavender
  • Fruity
    • Apple, melon, berries, stone fruit (apricot, peach, etc.)
  • Citrus
    • Orange, grapefruit, lemon, lime
  • Vegetal
    • Grass, hay, celery, onion, garlic
  • Herbal
    • Mint, black tea, green tea, dank
  • Woody
    • Pine, tobacco, oak, earthy, leather
  • Spicy
    • Clove, cinnamon, anise, pepper

There are several main essential oils found in hops that contribute a wide array of aromas1:

  • Myrcene
    • green, resinous
  • Humulene
    • piney, woody
  • Caryophyllene
    • woody
  • Farnesene
    • floral
  • Linalool
    • floral, orange
  • Geraniol
    • floral, rose, sweet

Hop Use Classification

Hops are also classified by their typical use in the brewing process:

  • Bittering
    • Bittering hops have higher concentrations of alpha acids (> 5% by weight) and may have lower concentrations of essential oils
  • Aroma
    • Aroma hops have lower concentrations of alpha acids (< 5% by weight) and higher concentrations of essential oils
  • Dual-Purpose
    • Dual-purpose hops are used as both bittering hops and flavor/aroma hops.


1Scott Janish. “Analysis of Hop Oils By Aroma Wheel Category” Accessed 02 Aug 2023.

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