What Is Bitterness in Beer And How to Measure It

When people say a beer is “bitter,” they’re usually talking about hops. But bitterness in beer is about more than just how it tastes, it’s about balance. Get it right, and your beer feels crisp, refreshing, or punchy. Get it wrong, and it might taste harsh, thin, or overwhelming.

That’s why brewers measure bitterness using IBU and why it’s a number worth testing, not guessing.

What Is IBU?

IBU stands for International Bitterness Units. It tells you how much iso-alpha acid (the main bitter compound from hops) is present in the beer.

1 IBU = 1 mg of iso-alpha acids per liter of beer.
The higher the IBU, the more bitterness is potentially perceived but perception depends on balance with sweetness, alcohol, and body.

You can have a 60 IBU hazy IPA that tastes smooth and juicy, and a 25 IBU lager that feels sharp and bitter. It all depends on context.

Where Bitterness Comes From

Bitterness in beer mainly comes from hops added during the boil. The heat causes alpha acids in the hops to transform into iso-alpha acids, which dissolve into the wort.

Factors that affect bitterness:

Hop variety and alpha acid %
Amount of hops used
Boil time (longer = more bitterness)
Wort gravity and pH
Late or dry hopping adds aroma, not IBU

Typical IBU Ranges by Style

Beer Style	Typical IBU Range	Balance Comment
Light Lager	8 – 15 IBU	Delicate bitterness
Pilsner	25 – 40 IBU	Crisp, sharp bitterness
Pale Ale	30 – 50 IBU	Balanced with malt
IPA	40 – 80+ IBU	Bitterness can be high but often softened by body and hops
Stout / Porter	25 – 50 IBU	Bitterness from hops + roasted malts
Sour Ales	5 – 15 IBU	Low bitterness to let acidity shine
Hazy IPAs	20 – 50 IBU	Soft and hidden due to haze and sweetness

Key takeaway: The same IBU can taste very different depending on the beer’s sweetness, alcohol, carbonation, and body.

Why You Should Lab-Test Bitterness (Not Just Calculate It)

Most brewing software estimates IBU based on hop additions but real life is messier. Things like:

Poor hop storage,
Wort pH changes,
Boil intensity,
Whirlpool losses,
Dry hop interaction,

…all affect how much bitterness ends up in the final beer.

That’s why real IBU testing using EBC Method 9.8 (or MEBAK equivalent) is critical:

UV-Vis spectroscopy measures actual iso-alpha acid concentration in your finished beer.
It reflects what the drinker will really perceive, not just what the recipe said.

For breweries, especially those entering competitions, exporting, or tweaking recipes, lab-tested IBU means trust and accuracy.

How to Understand Your IBU Result

At testmybeer.com, we give you accurate IBU results using EBC-compliant testing. Here’s how to think about your result:

IBU Value	What It Feels Like
0 – 10	No noticeable bitterness. Often found in sours, wheat beers, and some lagers.
10 – 25	Mild bitterness, balanced. Great for lighter styles.
25 – 50	Moderate bitterness. Standard for IPAs, pale ales, and balanced stouts.
50 – 80+	Strong bitterness. Watch out for balance with body and sweetness.
100+ (theoretical)	Past this point, taste perception flattens, the tongue can’t distinguish more. Still useful in marketing, but not always in flavor.

Final Thoughts

Bitterness is not just a number, it’s a feeling. But knowing your actual IBU helps you:

Stay true to the style,
Maintain recipe consistency,
Avoid surprises in flavor,
And label your beer honestly.

Calculated values can lie. EBC or MEBAK testing tells the truth and at testmybeer.com, we’re here to help you get that number right.

Send in your beer sample and we’ll tell you exactly how bitter it really is.