What Does IBU Mean in Beer?

The International Bitterness Units (IBU) scale is a measure of a beer’s bitterness.


It is a gauge of the concentration of bittering compounds such as isomerized and oxidized alpha acids and polyphenols. The scale ranges from 0 to 120, although technically, the bitterness can be higher.

The IBU scale measures the amount of bitter acids the lupulin supplies in a beer that comes from hops. To find its IBU number, the beer is extracted with an organic solvent, creating a solution that’s then exposed to ultraviolet light.

As the IBU number increases, the parts per million of iso-alpha acids and polyphenols register as more bitter on the tongue. However, the human palate is less able to detect differences above that range.

Understanding the IBU scale is essential for beer lovers who want to learn more about the taste of their favorite brews. This article will delve deeper into what IBU means and how it affects the taste of beer.

Understanding IBU

IBU stands for International Bitterness Unit, which is a scale used to measure the bitterness of beer.


The IBU scale ranges from 0 to 100, with 0 being the least bitter and 100 being the most bitter. The higher the IBU number, the more bitter the beer will taste.

The IBU scale is a measure of the concentration of iso-alpha acids in beer. These acids are formed during the brewing process when the hops are added to the wort. The longer the hops are boiled, the more iso-alpha acids are formed, and the higher the IBU rating of the beer.

It’s important to note that IBU is not a measure of the overall quality of a beer. A beer with a high IBU rating may not necessarily be better than a beer with a lower IBU rating. The IBU rating simply indicates how bitter the beer will taste.

When rating the IBU of a beer, brewers use a spectrophotometer to measure the amount of light absorbed by the beer. The amount of light absorbed is proportional to the concentration of iso-alpha acids in the beer, which is then converted into an IBU number.

The IBU scale is a useful tool for brewers to manage quality control and ensure consistency in their beer. It also helps consumers choose a beer that suits their taste preferences. For example, if someone enjoys a bitter taste in their beer, they may choose a beer with a higher IBU rating.

The Role of Hops in Beer

Hops are one of the essential ingredients in beer, alongside barley, yeast, and water.


They play an important role in shaping the flavor, aroma, and bitterness of beer. The bitterness of beer is measured in International Bitterness Units (IBUs). IBUs indicate how much bitterness there is in a particular beer.

Hop Varieties and Their Impact

There are many different hop varietals used in brewing, each with its own unique flavor and aroma profile. Some popular hop varietals include:

  • Cascade: This hop varietal is known for its citrusy and floral aroma and is often used in American Pale Ales.
  • Saaz: This hop varietal is known for its spicy and earthy aroma and is often used in Pilsners and lagers.
  • Centennial: This hop varietal is known for its floral and citrusy aroma and is often used in IPAs.

Different hop varietals can be combined to create complex flavor profiles in beer. Brewers can also adjust the amount of hops used in a beer to increase or decrease its bitterness.

Hop Bitterness and Aroma

Hops contain alpha acids that contribute to the bitterness of beer. During the brewing process, these alpha acids are isomerized, which means they are converted into bittering compounds. The concentration of these bittering compounds is measured in IBUs.

Different Beer Styles and Their IBU


IPA and Its IBU

India Pale Ale (IPA) is one of the most popular beer styles, known for its high IBU range. The IBU of an IPA typically ranges from 40 to 100, depending on the type of IPA. For example, West Coast IPAs are known for their high bitterness, while Hazy IPAs are known for their lower IBU and more fruity and juicy flavor.

Pilsner and Its IBU

Pilsners are a light lager beer style that originated in the Czech Republic. They have a lower IBU range of around 20-40, making them less bitter than IPAs. Pilsners are known for their crisp and refreshing taste, with a balance of maltiness and bitterness.

Lager and Its IBU

Lagers are a type of beer that undergoes a cold fermentation process, resulting in a clean and crisp taste. Light lagers, such as American lagers, have a low IBU range of around 5-10, while darker lagers, such as bocks, have a higher IBU range of around 20-30.

Porter and Its IBU

Porters are a dark beer style that originated in London. They have a moderate IBU range of around 20-40, with a balance of bitterness and sweetness. Porters are known for their roasty and chocolatey flavor, with a smooth and creamy mouthfeel.

Wheat Beer and Its IBU

Wheat beers, such as witbier and hefeweizen, are known for their light and refreshing taste, with a hint of citrus and spice. They have a low IBU range of around 10-20, making them less bitter than other beer styles. Wheat beers are often served with a slice of lemon or orange to enhance their citrusy flavor.

Different beer styles have different IBU ranges, which contribute to their unique flavor profiles. Craft beer enthusiasts can choose from a wide range of beer styles, from pale ales to stouts, each with its own IBU range and bitterness level.

The Brewing Process and IBU

When it comes to brewing beer, the International Bitterness Units (IBU) scale is an essential tool for brewers to achieve the desired balance between sweetness and bitterness.

a man checking beer distillation process facility

The IBU scale measures the relative bitterness of the beer, which is achieved by balancing notes of sweetness from sugars in the malted grains and the bitterness from hops.

Malt and Its Influence

Malt is a key ingredient in the brewing process, and it has a significant influence on the beer’s flavor profile. The malted grains used in beer production contain sugars that are essential for the fermentation process. These sugars are extracted from the malt during the mashing process, where the grains are soaked in hot water.

Different types of malt can be used in the brewing process, including barley, wheat, and rye. Each type of malt has a unique flavor profile, which can impact the final taste of the beer. For example, a beer made with a high percentage of roasted malt will have a darker color and a more robust flavor profile.

The Boiling Process

The boiling process is a critical step in the brewing process that affects the beer’s bitterness. During the boil, hops are added to the wort, which is the liquid that is extracted from the malted grains during the mashing process.

The alpha acids in the hops are isomerized during the boil, which creates bitter compounds that contribute to the beer’s overall bitterness.

The length of the boil and the amount of hops added can significantly impact the beer’s IBU rating. A longer boil time and a higher hop addition will result in a beer with a higher IBU rating and a more bitter taste.

Brewers can also adjust the IBU rating by adding hops at different stages during the boil, such as at the beginning for more bitterness or at the end for more aroma.

Please drink responsibly, be fully accountable with your alcohol consumption, and show others respect.

Written by Rocco

Rocco is a Florida State University alumnus with years of bartending and hospitality experience. From slinging hundreds of vodka sodas a night in jam-packed college bars to serving carefully crafted cocktails in upscale restaurants, there’s not much he hasn’t done behind a bar. Now, Rocco shares his knowledge and passion for all things alcohol-related here on My Bartender for bibulous readers everywhere to enjoy.

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