What really is the IBU and why do we care so much in beer?
At first glance, that mysterious acronym, IBU, sounds like a code for engineers, but in reality it is the key to understanding how loved or bitter our beer creation will be. The IBU, or international bitter units, measures the concentration of iso-alfa-acids dissolved in each liter of beer: basically, how many milligrams of these compounds are for each volume. Who says that beer cannot be a science and art at the same time, is wrong, because each level of IBU reveals a world of decisions in the manufacturing process.
Hops: The main character in the history of flavor
In the production cycle, hops additions are the actors that dictate the final nature of beer. The quantity and time when they are introduced in the process are crucial. When we place it at the beginning of the boil, we are betting on an intense and lasting bitterness, due to the greater isomerization of hops resins. However, this technique also risks losing the delicate aromas and aromatic notes that the hops can offer.
On the other hand, late additions – almost at the end of the boil – favor the conservation of fresher aromas and flavors, but do not achieve the same level of bitterness. The choice of when to add the hops defines whether our beer will be more aromatic, more bitter or a perfect combination of both.
The balance between aroma, flavor and bitterness: a dance dance
The process is like a choreography. Inspired by graphs that show how different compounds are released during boiling, we can understand the evolution of beer in real time. The aroma curve (in green) reveals that its peak occurs at 7 minutes, but also the volatilization and loss of aromas in later stages, especially in more energetic fermentations such as in the beers Ale.
The flavor profile (blue) shows that the flavors penetrate the must mostly in the first 20 minutes, but then begin to disappear as essential oils volatilize. The bitterness (red), on the other hand, maintains a continuous presence, from the first minutes to about the full boiling time, reaching its maximum around 60 minutes.
And how is all this calculated? The mathematical magic of the beer style
For those who enjoy designing their own beer, understanding the calculation of the IBU may seem intimidating, but in reality it is an exercise of logic and precision. The basic formula involves multiplying the amount of hops in grams, the percentage of alpha-acids and the efficiency of the process, adjusting by the must of must. Thus, we can estimate how many milligrams of iso-alfa-acids we are introducing per liter.
Then, to determine how much of that bitterness is released in beer, we turn to use coefficients, which vary according to the method and technique used. From Rager type graphics to glide-nitshet tables, each method gives us an idea of how much the process affects our aromatic and bitter profile, allowing precise adjustments for the final result.
A practical example for curious brewers
Suppose we want to create a beer with a moderate level of bitterness, just around 30 IBU. We start from a 20-liter must with an initial density of 1060. We add three times 15 grams of Cascade hops, with a content of 7.2% alpha-acids, in key moments: 60, 20 and 5 minutes before the end of the boil.
After applying the use coefficients corresponding to each addition, we reach an estimated total of 28 IBU, a perfect balance between aroma and bitterness. This process not only helps perfect recipes but also opens doors to experiment with different hops, percentages and times, achieving sublime and personalized profiles.
The future of the beer teacher: beyond the numbers
In short, the concept of IBU and the measurement of bitterness are tools that, used with creativity and precision, allow brewers to design unique sensory experiences. The key is to understand how decisions during the process affect the final profile, and how each of those curves in time tells a different story.
While we move towards new techniques and technologies, which will remain constant is the passion to create and perfect each lot. Because, deep down, each drop of beer represents a balance between science, art and that spark that makes us provide again and again.
