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Oak casks on a shelf (Photo: Anthony Riera on Unsplash)

Simulated barrel maturation | How do the aromas and color of spirits develop during barrel maturation? What roles do the degree of toasting and the type of wood play? What is the most practical method for determining the phenolic compounds and the volatile substances in wood, such as higher alcohols, aldehydes, esters and lactones? With gas and liquid chromatography? The authors recreated the process of aging in wooden barrels in the laboratory and analyzed the processes of extraction, color and aroma formation.

Beer analyses test beers | During dry hopping, extraction of hop aroma poses multiple challenges for brewers, as has been described in Part 1 of this series of articles. In this second part of the series of articles, a method on a laboratory scale is presented in which extraction of hop aroma is carried out by re-dilution.

Popular drink | Hard seltzer, a low-calorie and low-carbohydrate alcoholic drink, is one of the trendiest current alternatives in the alcoholic beverage industry. To meet the expectations of consumers for consistent taste and the requirements for correct labelling and declaration of the alcohol content, an accurate, simple, and fast analytical solution is required. Anton Paar conducted a study to explore whether different analytical methods conform to an officially acknowledged reference method (e.g., distillation).

Measuring turbidity and color | Color has a significant impact on how a consumer perceives the quality of a glass of beer. Defined by type and brand, the consumer has a clear expectation of what a beer should look like. Turbidity has found its way back into beer. For decades only seen in specific beers like wheat beer or Belgium-styled beer, craft brewing has brought haze back into the glass. How do color and turbidity influence each other? What do you need to be aware of if measuring both of them at the same time? This article spotlights two different technologies used in breweries for inline measurement of color, small and large particles, and handle buildup or fouling on optical windows.

Decision-making tools | The good news is that the selective properties of beer prevent the growth of pathogens; however, there are various types of microorganism that thrive fairly well in the conditions beer provides. They can affect the appearance, odour and taste of a beer. This article provides a summary of the most common beer spoilers, standard detection methods and recommended courses of action for microbiological problems.

Gently mixing products | This is a topic under perpetual discussion. Economic comparisons, in particular, form the basis for making decisions when choosing a process or when considering the investment required to implement a continuous process. Aside from economic considerations, aspects such as the duration of the process, how well it can be automated and the level of product losses as well as the costs and labor associated with cleaning and maintenance are all very important for manufacturers concerned with upholding high quality standards, since these factors affect the quality and influence the final product during the process.

Stress during brewing? | During the brewing process, yeast cells are subjected to a multiplicity of stress factors simultaneously (fig. 1). These stressors influence the physiological condition – defined as yeast vitality – of living cells and, thus, also have an impact on their morphology.

Beer quality | Oxygen impacts negatively on beer quality in terms of flavour, stability and quality. No oxygen, if at all possible, should get into the product after fermentation. For this reason, residual oxygen is monitored in the trace range at critical locations with in-line sensors or portable devices.

New methods | On 1 July 2021, the European Brewery Convention (EBC) and the American Society of Brewing Chemists (ASBC) published two international methods on Free Amino Nitrogen and β-glucans measurement in wort by automated discrete analysis and two new International Methods in microbiology developed over the past three years by experts on both sides of the Atlantic Ocean.

Analysis of bitter substances | In beer production, the development of modern analyses provides possibilities of extending the analytical spectrum. It is possible to investigate the detailed path of individual compounds from raw materials to the finished beer, using mass spectroscopy. The hard resin fraction of hops that mainly consists of polar i.e. easily water soluble bitter substances is ascribed a special role in terms of dry hopping. This makes efficient transfer of these substances from hops to beer possible. The present contribution describes the compounds involved, as well as the flavour contribution they make to beer bitterness.

Ageing behaviour | Forced ageing at 40 °C is one of the most common methods for assessing sensory stability of pale lager beers. However, different aroma profiles frequently arise in practice compared to natural ageing at 20 °C. The present article describes the ageing characteristics of pale lager beers during forced and natural ageing, both in sensory and in analytical terms. The contribution is based on research results that have been published in BrewingScience, May/June 2018, volume 71.