IBU question - lager vs Kolsch

[leedspointbrew]

At Toms River Brewin g, Toms River NJ. Tried 5 oz samples of a pale lager 30 IBU (which did taste like a lager, not a pale ale), and a Kolsch 18 IBU,- lager did not taste appreciably more bitter than Kolsch (pictured). Color looked very similar, but they were clearly different beers. I'm a novice, so forgive my ignorance.

 

[DBhomebrew]

IBUs are not the only factor in perceived bitterness. Gravity, residual sugars/dextrins, ABV, attenuation, carbonation, mineral levels etc, etc all come into play.

Still very rough, a BU:GU comparison is a better indicator of bitterness in the glass than IBUs alone.

 

[Sammy86]

You also have to remember that the yeast choice, water chemistry and a bunch of other factors are going to impact perceived bitterness and flavor of the beer.

I normally brew a 12 gallon split batch of German Pils/Kolsch with the only difference being the yeast and they are clearly different flavored beers.

 

[leedspointbrew]

You also have to remember that the yeast choice, water chemistry and a bunch of other factors are going to impact perceived bitterness and flavor of the beer.

I normally brew a 12 gallon split batch of German Pils/Kolsch with the only difference being the yeast and they are clearly different flavored beers.

With the same IBU

 

[fluketamer]

grok had some interesting things to add:

what affects the bitterness of a liquid?
The bitterness of a liquid is influenced by several factors, primarily related to its chemical composition and how it interacts with your taste buds. Here’s what affects it:

1. Chemical Compounds: Bitter taste is often triggered by specific compounds like alkaloids (e.g., caffeine, quinine), tannins (found in tea and wine), or certain phenolic compounds. The presence and concentration of these molecules determine how bitter a liquid tastes. For example, quinine in tonic water gives it that sharp, bitter edge.
2. Concentration: The more concentrated the bitter compound, the stronger the bitterness. Think of black coffee—dilute it with water, and the bitterness mellows out.
3. pH Level: Acidity or alkalinity can amplify or mask bitterness. Highly acidic liquids (low pH) might overshadow bitterness with sourness, while alkaline conditions (high pH) can enhance it. This is why adding lemon to tea can shift the flavor balance.
4. Temperature: Hot liquids often taste more bitter because heat increases the volatility of compounds, making them more detectable by your taste receptors. Cold coffee, for instance, tends to feel less bitter than hot coffee.
5. Other Flavors: Sweetness, saltiness, or fat content can counteract bitterness. Sugar in coffee or cream in tea softens the bitter bite by competing for your taste buds’ attention.
6. Individual Perception: Your genetics play a role—some people have more sensitive bitter taste receptors (TAS2R genes). What’s mildly bitter to one person might be unbearable to another.

so for me it seems like there are a lot of other variables aside from ibus that will determine how bitter the beer tastes.

 

[Bobby_M]

Don't forget that brewing software is predicting IBU based on a bunch of assumptions and it's not perfect. Hops also lose alpha acids during storage. The brewery is just listing estimated IBUs and they may be closer together than they think.

 

[Sammy86]

With the same IBU

Correct. I boil 14.5 gallons, hop per my recipe, chill, split into two 6 gal. Fermentors, pitch Kölsch yeast into one, Diamond Lager yeast into the other and bing bang boom two completely different beers.

 

[HM-2]

Difference in carbonation could be another factor too. Higher level of carbonation can create the perception of higher bitterness.