How is beer quality tested?

Answered by Roy Gibson

As a sommelier and brewer, I have had the opportunity to delve into the world of quality testing and ensure that every pint that reaches the customer's hands is of the highest standard. Beer quality is a complex and multi-faceted aspect of the process, involving various tests and measurements at different stages of production.

During the maturation process, several key factors are evaluated to assess the beer's quality. One of the most important tests is for content, as it directly impacts the beer's flavor and body. This is typically determined through the use of a hydrometer or a refractometer, which measures the specific gravity of the liquid. By comparing the specific gravity before and after fermentation, we can calculate the alcohol content.

Another crucial aspect of beer quality testing is the evaluation of color. Color not only influences the appearance of the beer but can also indicate potential issues during the brewing process. A spectrophotometer is commonly used to measure the beer's color in terms of International Bitterness Units (IBU) or the Standard Reference Method (SRM). These measurements give a clear indication of the beer's hue, from pale and golden to dark and robust.

PH levels are also closely monitored during maturation. pH affects the beer's stability and taste, as different pH levels can enhance or diminish certain flavors. A pH meter is used to measure the acidity or alkalinity of the beer, with the ideal range typically falling between 4.0 and 4.5 for most beer styles.

Density, or specific gravity, is another parameter that is routinely tested during maturation. This measurement helps determine the beer's body and carbonation levels. A densitometer is used to measure the density of the beer and compare it to the expected values for a given style.

One important compound to monitor during maturation is volatile diacetyl, also known as VDKs. Diacetyl is a natural byproduct of fermentation and can impart a buttery or butterscotch flavor to the beer if present in excessive amounts. Gas chromatography/mass spectrometry is commonly used to quantify diacetyl levels and ensure that they are within acceptable limits.

Additionally, hop aroma compounds are analyzed during maturation. These compounds contribute to the beer's aroma and can greatly enhance the overall drinking experience. Gas chromatography/mass spectrometry is employed to identify and quantify the specific hop aroma compounds present in the beer, ensuring that they align with the desired flavor profile.

Moving on to the bright tank, where the final stages of beer production take place, several quality tests are conducted to ensure the beer is ready for packaging and consumption. Similar to the maturation stage, alcohol content, color, pH, and density are measured to ensure consistency and adherence to style guidelines.

Turbidity, or cloudiness, is an important characteristic to evaluate at the bright tank stage. Excessive turbidity may indicate issues with filtration or settling, resulting in an unappealing appearance. A turbidimeter is utilized to measure the beer's clarity and identify any potential problems.

Beer quality testing is a comprehensive process that occurs at various stages of production. From maturation to the bright tank, a range of tests are conducted to assess alcohol content, color, pH, density, turbidity, and the presence of specific aroma compounds. These tests help brewers maintain consistency, ensure adherence to style guidelines, and ultimately deliver a high-quality product to beer lovers around the world.