In the pursuit of crafting award-winning artisanal beer, integrating advanced scientific methods into the brewing process is essential. One such method, UV-Visible (UV-Vis) spectrophotometry, has proven to be an invaluable tool for breweries focused on maintaining and improving beer quality. This technology offers a cost-effective, efficient, and reliable means of analyzing various critical parameters in beer production, making it an indispensable asset for quality assurance and control (QA/QC) in the brewing industry.
An article published by a brewing industry news source discussed the Role of UV-Vis spectrophotometry in brewing, especially when dry hopping beer.
Advantages of UV-Vis Technology
Brewery operations usually have dozens of quality checkpoints for every single batch of beer, which extend from the brewhouse all the way to the final package and beyond. Quality programs focus on yeast quality, fermentation consistency/performance, microbiological testing, packaging quality, refermentation monitoring, and sensory panels. And that testing involves many different instruments, including UV-Vis spectrophotometers.
UV-Vis spectrophotometry is a versatile analytical technique that measures the absorbance of UV and visible light by a sample. This method is particularly useful in the brewing industry due to its ability to quantify important beer analytes such as volatile diacetyl ketones (VDKs), acetaldehyde, and sulfur dioxide, as well as assess important beer properties like color and bitterness.
VDKs occur in beer as a by-product of the fermentation process. Increased VDKs can negatively alter the flavor of beer giving a buttery flavor. Yeast serves to reabsorb VDKs over multiple days, so the ability to measure the concentration of VDKs in beer can increase brewing productivity saving time and money.
By providing precise and reproducible measurements, UV-Vis spectrophotometry helps brewers maintain consistent quality and flavor in their products.
Practical Applications in Brewing: Dry Hopping
UV-Vis spectrophotometry provides quantifiable data that can enhance the overall quality control process. By incorporating spectrophotometric measurements, breweries can quickly obtain objective data that help in identifying deviations and maintaining consistent quality across batches.
UV-Vis spectrophotometry is employed in various routine tests within the brewing process. For example, it is used to measure beer color and bitterness, both of which are critical parameters for ensuring the desired characteristics of the final product.
One example using UV-Vis in the beer industry involves dry hopping. Dry hopping beers is a critical component to hop-forward beers.
Dry hopping is a widely employed technique in the brewing industry, particularly popular for enhancing the aroma and flavor profile of hop-forward beer styles such as India Pale Ales (IPAs), Pale Ales, and certain lagers. Unlike traditional hopping methods that add hops during the boil, dry hopping involves adding hops to the beer after the primary fermentation process.
However, as noted in this case study, the process of dry hopping often disrupts the maintenance of otherwise terminal vicinal diketone (VDK) values. This phenomenon has led to cellaring nightmares with highly extended VDK stands that can have numerous negative quality impacts on the beer.
With VDK quantification by [UV-Vis] spectrophotometry, key variables in the dry hopping process can be identified, which can help avoid this issue.
Dry Hopping Process
Dry hopping is typically done after the primary fermentation has completed. This can be during secondary fermentation, in the conditioning tank, or even in the keg or bottle. Hops are added directly to the fermenter or conditioning vessel. This can be done by simply adding hop pellets, whole cone hops, or hop extracts. The hops are usually left in the beer for a few days to a couple of weeks, depending on the desired intensity of hop aroma and flavor. Brewers often choose aromatic hop varieties such as Citra, Mosaic, Cascade, Simcoe, and Amarillo, which are known for their strong aromatic qualities.
As mentioned, UV-Vis spectrophotometry can help identify key variables in the dry hopping process which can affect the hop flavor, aroma, and consistency.
Summary
Incorporating UV-Vis spectrophotometry into the brewing process offers numerous benefits for both food and beverage scientists and brewery owners. In addition to checking quality during the dry hopping process, UV-Vis spectrophotometry aids in monitoring other important analytes, acetaldehyde, and sulfur dioxide, which can also significantly impact the flavor and stability of beer. By regularly testing for these analytes, brewers can monitor their batches to help ensure that their beer meets the highest quality standards.
Another advantages of UV-Vis spectrophotometry is its cost-effectiveness compared to other advanced analytical techniques like High-Performance Liquid Chromatography (HPLC) or Gas Chromatography-Mass Spectrometry (GC-MS). These more complex methods, while highly accurate, can be prohibitively expensive for many breweries. In contrast, UV-Vis spectrophotometry offers a more affordable solution without compromising on accuracy or reliability. Additionally, UV-Vis spectrophotometers are user-friendly and adaptable to various testing needs
You can read more about one brewer’s experience using UV-Visible (UV-Vis) spectrophotometry for QA/QC testing involving the dry hopping process in this case study.
Additional Resources
- *Case Study: Let’s talk Quality Control with Max Kravitz, pFriem Family Brewers
- UV-Vis Spectrophotometers for Food and Beverage
- BeerCraft™ Software
- UV-Vis Spectrophotometer Educational Resources