The ultimate guide to spectroscopic methods in beer

What are the different spectroscopic methods and what are their advantages? We have been speaking with our in-house senior data scientist, Kasper Winther Jørgensen, about spectroscopic analysis and the advantages of using FTIR compared to NIR when analyzing craft beer.


The craft brewing industry is constantly evolving, and many breweries starting as small micro-breweries are now reaching considerable beer production totals each year. With production growth, many craft breweries are reaching a point where it is more beneficial to use in-house quality control methods rather than outsourcing this key activity to external labs. Spectroscopy is becoming a more and more common method by which breweries track and monitor their beer production and fermentation.


So, what is spectroscopy? And what are the different spectroscopic methods and their advantages? We have been speaking with our in-house senior data scientist, Kasper Winther Jørgensen, about spectroscopic analysis and the advantages of using FTIR compared with NIR when analyzing craft beer.


What is FTIR? What is NIR? And how does infrared spectroscopy work?

Broadly, infrared spectroscopy is a principle where light interacts with organic matter in different ways. By measuring light’s interaction with different materials, you get valuable insight about the material’s composition.


Near-Infrared (NIR) is one technique that is often used in spectroscopic analysis. It uses the electromagnetic spectrum between 700nm and 2500nm and is an accurate and rapid analysis reference method that is well-suited for quantitative determination of the major constituents in most types of food and agricultural products.

FTIR stands for Fourier Transform Infrared and is a spectroscopic technique that makes use of the electromagnetic spectrum from 2500nm and 25000nm. This is the ‘mid-infrared’ region, and this is why FTIR is sometimes called Mid IR. 


The mid-infrared spectrum 2500nm – 25000nm is broad in comparison to, for example, NIR (800 – 2500 nm). Because the spectra generated by an FTIR analyzer are based on many data points, it provides a highly accurate spectral representation of the sample under analysis. In fact, the accuracy and repeatability of results are often at least as good, if not better, than traditional chemical analysis, but obviously hard to prove. At the same time, measurements take less than a minute and are chemical-free. 


  Electromagnetic spectrum


Compared to traditional wet chemistry analysis, using infrared spectroscopy for quality control analysis is an easy-to-use, accurate, low-cost method. In a brewery, infrared spectroscopy analysis can save time and money in many ways and is a non-destructive analysis method that allows data to be collected without the need to throw away raw material. Additionally, you perform multiple analyses simultaneously of one sample with little or no sample preparation, and you can take these measurements around the clock.


How do different spectroscopic methods give insights into malt and beer analysis? 

FOSS has been using NIR since the 70s and NIR is an excellent way for measuring moisture percentage, starch, and protein in grain and other raw materials before the brewing starts. It is also used when analyzing cheese, cream and unhomogenized milk as the penetration depth is important to obtain a representative measurement throughout a sample with an uneven consistency.

While this is great for grains and solid materials, for most liquids, FTIR has turned out to be a more reliable solution.


The dairy industry was the first to benefit from the convenience and speed of FTIR analysis through pioneering FOSS solutions introduced in the 1980s and FTIR is now the leading methodology to test milk and dairy products for fat and protein content.


FTIR analysis has also become an important tool for winemakers ever since FOSS introduced FTIR analysis to the industry in 1999. It is not that winemakers could not make high-quality wine before, but now they can do it more consistently with objective data available to cross-reference their instincts and judgement. We also use FTIR technology in our BeerFoss™ FT GO to bring these benefits to the craft beer industry.


Where in the brewing process can you use spectroscopic analysis?

The short answer is that you can use spectroscopic analysis in every stage of brewing process. From raw material analysis to finished beer. FOSS has been using different technologies to support grain growers and maltsters over the last six decades.


With FTIR spectroscopy, you can measure ABV, density, gravity, real extract, RDF, pH, calories (and more) to help you track production data and ensure that your quality standards are consistent.

Craft breweries often view themselves as brewing better tasting and better quality beverages than macro beers, but is taste and quality something that can be measured with spectroscopy? Taste is a very subjective thing, but quality is certainly something that can be measured.

When speaking about beer, quality control is about ensuring that a certain style meets the specifications that have been made for the specific style of beer. This includes specific combinations of barley and hops, fermentation, temperature, and finishing of the product. You also need to be sure that you hit the ABV listed on your labels to avoid taxation issues.



(Example of wavelength of a beer sample)


With Near Infrared (NIR) and Mid Infrared (FTIR) spectroscopy, you can measure all of the key parameters, from ABV to density to real extract, to give insights into the wild world of fermentations, and be sure you are brewing the exact beer you want every time. By tracking and recording the data values throughout production and fermentation through to packaging, you can ensure that specifications are met, and consistency is achieved.


In summary, what are the benefits of FTIR in craft beer?

The benefits of FTIR in beer are plenty. First of all, the mid-infrared spectrum of 2500nm–25000nm is broad in comparison to, for example, NIR (800–2500nm) and because the spectrums generated by an FTIR analyzer are based on many data points, it provides a highly accurate spectral representation of the sample under analysis.


Secondly, FTIR is more sensitive and can therefore measure both low and high alcoholic beer with greater accuracy than NIR. It is also much more adaptable when measuring all kinds of sour, hoppy or sweet beer. Samples do not need to be degassed or filtered prior to analysis since FTIR is able to measure the critical alcohol molecules and ignore the particle ‘noise’.


On top of this, FTIR is not a single-purpose measurement solution. New features can be added depending on customer needs and we are constantly working on new features to be added. A great example is FTIRs ability to measure hazy beer. This is a great advantage for craft breweries that are often much more experimental and constantly looking for new ways of producing and using different ingredients when creating new types of beer.

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