When you taste a beer and you are surprised by a fruity aroma or a smoked touch, you have probably been in the presence of chemical compounds that, although small, have a huge impact on sensory experience. These protagonists, the esters and phenols, play different roles in the beer world and beyond the clichés, understand them opens the doors to create more interesting and controlled flavors.
The fruit secrets of the esters: beyond the aroma of pear
Have you ever perceived a banana or apple aroma in your beer? Most likely, you are savoring a ester, an organic compound produced by yeasts during fermentation. These aromatic ingredients, which sometimes evoke sweetness, flood or even honey notes, derive from chemical reactions between acids and alcohol that are generated in the process.
Within beer science, there are three key variables that determine how much and what type of esters are formed: the composition of the must, the type of yeast and the conditions of the fermentation environment.
What influences the profile of esters?
A must with high concentrations of sugars, zinc and free amino acids tends to produce more esters. On the other hand, high levels of dissolved oxygen or lipids in the must can suppress your formation. The choice of yeast also makes a difference: some, such as those used in German beers of wheat, are famous for throwing banana aromas that almost become characteristic of the style.
The environment and fermentation conditions reinforce this variability. The highest and most narrow fermenters generate less esters, due to the greater pressure and accumulation of CO₂, compared to open or less deep containers.
Phenols: aromas that you don’t always want but also seduce
Phenols in beer are not an absolute mystery, but they are often associated with aromas ranging from the clove to medicinal or smoked notes. These compounds, which can be very subtle or easily detectable, are usually considered undesirable in many beers, although in certain styles they have their place.
Where do these phenols come from and why some styles celebrate them while others dodge them? The answer passes through various sources, from water to special malts and elaboration processes.
Sources and factors that determine phenols in beer
A water with the presence of phenols can transfer these aromas to beer, and in some cases, smoked or seasoned malts such as the Rauchmalt provide unique notes. The nature of these compounds can also be induced by chemicals such as chlorine or bromine, present in water or residual in the equipment if they are not properly cleaned.
Yeasts and bacteria are also responsible for specific phenols. For example, in beers of wheat or Belgian style, the clove character comes from 4-vinil -guayacol, derived from ferulic acid; A special interest in these cases is to increase the production of this compound through high fermentation temperatures or specific management in the process.
Finally, products such as Bretanomyces can produce phenols with terrifying and robust touches, providing a dimension that some style lovers enjoy without prejudice.
In beer art, dominating these compounds offers the possibility of creating complex aromatic profiles, playing with environmental variables and raw materials to design unique and memorable flavors.
