Analysis of beers from an 1840s' shipwreck

Increased Rate of Yeast Cultivation from Packaged Beer with Environmentally Relevant Anaerobic Handling

Beer production necessitates oxygen exclusion for the proper packaging and aging of the beer. Standard operating procedures, including those for quality testing, involve culturing microbes from packaged beer exposed to atmospheric oxygen, despite the generalized fact that packaged beer is an anaerobic environment. Our research goal was to apply an environmentally relevant culturing approach to improve yeast cultivation from bottled beer by attempting to ameliorate transplant shock. This is applicable to uniquely scrutinous quality assurance/control objectives and/or to grand cultivation goals, such as ancient beer samples. Although yeasts have the genetic capacity of oxygen protection, their epigenetic/biochemical states within anaerobic packaging may not adequately protect all cells from reactive oxygen species (ROS) at the moment of opening. Soon after opening, beer yeasts were found to be catalase negative, indicating deficient protection from at least one ROS. The general reduction/inhibition of growth was observed when the beer yeast was exposed to ROS in media, and atmospheric bottle opening was found to expose beer yeast to significantly increased levels of ROS. Our primary finding is that different oxygen handling methodologies (aerobic/microaerophilic/anaerobic) significantly impact the viable Saccharomyces yeast recovery rates of Bamberger's Mahr's Bräu Unfiltered Lager. Immediate anaerobic handling improved cultivation success rates, with significantly higher colony forming units (CFU)/mL being cultured, and reduced the volume of beer required to recover viable yeast. Aerobic standard operating procedures have mainly been developed to harvest yeast on large volumetric samples and/or samples with high viable cell numbers, but these procedures may be suboptimal and may underrepresent potential viable cell numbers. IMPORTANCE Procedures of beer production and packaging exclude oxygen to create a shelf-stable anaerobic environment, within which any viable organisms are stored. However, standard methodologies to cultivate microbes from such environments generally include opening in an oxygenated atmosphere. This study applies environmentally relevant culturing methods and compares the yeast recovery rates of beers handled in various oxygen conditions. When beer bottles were opened in anoxic conditions, higher colony counts were obtained, so a smaller volume of beer was required to recover viable cells. The yeast in beer, stored anaerobically, may not be biochemically prepared to fully protect cells from oxygen at the moment of opening. Negative catalase activity showed beer yeasts' vulnerabilities to reactive oxygen. Atmospheric opening may reduce viability, causing the underreporting of viable cells. Anaerobic opening could increase the odds of successfully detecting/cultivating viable cell(s) that are present, which is pertinent to uniquely stringent quality screens and ambitious culturing attempts from rare samples.

Archeochemistry reveals the first steps into modern industrial brewing

A historical beer, dated to the German Empire era, was recently found in northern Germany. Its chemical composition represents a unique source of insights into brewing culture of the late nineteenth century when pioneer innovations laid the foundations for industrial brewing. Complementary analytics including metabolomics, microbiological, sensory, and beer attribute analysis revealed its molecular profile and certify the unprecedented good storage condition even after 130 years in the bottle. Comparing its chemical signature to that of four hundred modern brews allowed to describe molecular fingerprints teaching us about technological aspects of historical beer brewing. Several critical production steps such as malting and germ treatment, wort preparation and fermentation, filtration and storage, and compliance with the Bavarian Purity Law left detectable molecular imprints. In addition, the aging process of the drinkable brew could be analyzed on a chemical level and resulted in an unseen diversity of hops- and Maillard-derived compounds. Using this archeochemical forensic approach, the historical production process of a culturally significant beverage could be traced and the ravages of time made visible.

Preserving the food preservation legacy

This paper deals with the question about how early humans managed to feed themselves, and how they preserved and stored food for times of need. It attempts to show how humans interacted with their environments and demonstrate what lessons can be learnt from the about 3.4 million years of food processing and preservation. It includes a discussion about how hominins shifted from consumption of nuts and berries toward meat and learnt to control and use fire. Cooking with fire generated more food-related energy and enabled humans to have more mobility. The main trust of the paper is on historical food preservations, organized from the perspectives of key mechanical, thermal, biological and chemical processes. Emerging food processes are also highlighted. Furthermore, how humans historically dealt with food storage and packaging and how early humans interacted with their given environments are discussed. Learnings from the history of food preservation and culinary practices of our ancestors provide us with an understanding of their culture and how they adapted and lived with their given environments to ensure adequacy of food supply. Collaboration between food scientists and anthropologists is advocated as this adds another dimension to building resilient and sustainable food systems for the future.

Decomposing the molecular complexity of brewing

The compositional space of a set of 120 diverse beer samples was profiled by rapid flow-injection analysis (FIA) Fourier transform ion cyclotron mass spectrometry (FTICR-MS). By the unrivaled mass resolution, it was possible to uncover and assign compositional information to thousands of yet unknown metabolites in the beer matrix. The application of several statistical models enabled the assignment of different molecular pattern to certain beer attributes such as the beer type, the way of adding hops and the grain used. The dedicated van Krevelen diagrams and mass difference networks displayed the structural connectivity of the annotated sum formulae. Thereby it was possible to provide a base of knowledge of the beer metabolome far above database-dependent annotations. Typical metabolic signatures for beer types, which reflect differences in ingredients and ways of brewing, could be extracted. Besides, the complexity of isomeric compounds, initially profiled as single mass values in fast FIA-FTICR-MS, was resolved by selective UHPLC-ToF-MS² analysis. Thereby structural hypotheses based on FTICR’s sum formulae could be confirmed. Benzoxazinoid hexosides deriving from the wheat’s secondary metabolism were uncovered as suitable marker substances for the use of whole wheat grains, in contrast to merely wheat starch or barley. Furthermore, it was possible to describe Hydroxymethoxybenzoxazinone(HMBOA)-hexosesulfate as a hitherto unknown phytoanticipin derivative in wheat containing beers. These findings raise the potential of ultrahigh resolution mass spectrometry for rapid quality control and inspection purposes as well as deep metabolic profiling, profound search for distinct hidden metabolites and classification of archeological beer samples.

Lactobacillus backii and Pediococcus damnosus isolated from 170-year-old beer recovered from a shipwreck lack the metabolic activities required to grow in modern lager beer

In 2010, bottles of beer containing viable bacteria of the common beer-spoilage species Lactobacillus backii and Pediococcus damnosus were recovered from a shipwreck near the Åland Islands, Finland. The 170-year quiescent state maintained by the shipwreck bacteria presented a unique opportunity to study lactic acid bacteria (LAB) evolution vis-a-vis growth and survival in the beer environment. Three shipwreck bacteria (one L. backii strain and two P. damnosus strains) and modern-day beer-spoilage isolates of the same two species were genome sequenced, characterized for hop iso-α-acid tolerance, and growth in degassed lager and wheat beer. In addition, plasmid variants of the modern-day P. damnosus strain were analyzed for the effect of plasmid-encoded genes on growth in lager beer. Coding content on two plasmids was identified as essential for LAB growth in modern lager beer. Three chromosomal regions containing genes related to sugar transport and cell wall polysaccharides were shared by pediococci able to grow in beer. Our results show that the three shipwreck bacteria lack the necessary plasmid-located genetic content to grow in modern lager beer, but carry additional genes related to acid tolerance and biofilm formation compared to their modern counterparts.

Assessment of beer quality based on foamability and chemical composition using computer vision algorithms, near infrared spectroscopy and machine learning algorithms

BACKGROUND

Beer quality is mainly defined by its colour, foamability and foam stability, which are influenced by the chemical composition of the product such as proteins, carbohydrates, pH and alcohol. Traditional methods to assess specific chemical compounds are usually time-consuming and costly. This study used rapid methods to evaluate 15 foam and colour-related parameters using a robotic pourer (RoboBEER) and chemical fingerprinting using near infrared spectroscopy (NIR) from six replicates of 21 beers from three types of fermentation. Results from NIR were used to create partial least squares regression (PLS) and artificial neural networks (ANN) models to predict four chemometrics such as pH, alcohol, Brix and maximum volume of foam.

RESULTS

The ANN method was able to create more accurate models (R²  = 0.95) compared to PLS. Principal components analysis using RoboBEER parameters and NIR overtones related to protein explained 67% of total data variability. Additionally, a sub-space discriminant model using the absorbance values from NIR wavelengths resulted in the successful classification of 85% of beers according to fermentation type.

CONCLUSION

The method proposed showed to be a rapid system based on NIR spectroscopy and RoboBEER outputs of foamability that can be used to infer the quality, production method and chemical parameters of beer with minimal laboratory equipment. © 2017 Society of Chemical Industry.

Analysis of 100-Year-Old Beer Originated from the Czech Republic

Three bottles of different beers were found in 2015 during a reconstruction of the brewery of the Raven Trading s.r.o. company in Záhlinice, Czech Republic. Thanks to good storage conditions, it was possible to analyze their original characteristics. All three bottles contained most probably lager type beer. One beer had sulfuric and fecal off-flavors; it was bright with the original extract of 10.3° Plato. The second beer, with an original extract of 7.6° Plato, was dark and very acidic, resembling Lambic. DNA analysis proved the presence of Dekkera bruxellensis, which corresponded to its chemical profile (total acidity, FAN, ethyl acetate, total esters). The third beer contained traces of carbon dioxide bubbles, was light brown and slightly bitter, with an original extract 10.4° Plato. Because it obviously underwent a natural aging process, sweetness, honey, and fruity off-flavors were detected and transformation products of iso-α-acids were found.

Chemical messages in 170-year-old champagne bottles from the Baltic Sea: Revealing tastes from the past

The composition of 170-y-old champagne samples found in a shipwreck in the Baltic Sea constitutes a remarkable and unprecedented example of long-term combinatorial chemistry, which can occur in such sealed 750-mL microlaboratories. Multiple analytical tools, including metabolomics, metallomics, and sensory analysis, were combined to characterize the molecular diversity of these champagnes having aged in close-to-perfect conditions at the bottom of the sea. The analyzed champagnes retained intrinsic features allowing us to shed light on the winemaking practices in use in the middle of the 19th century. Therefore, this archeochemistry approach enabled us to rewrite a piece of our cultural heritage.

Archaeochemistry as the application of the most recent analytical techniques to ancient samples now provides an unprecedented understanding of human culture throughout history. In this paper, we report on a multiplatform analytical investigation of 170-y-old champagne bottles found in a shipwreck at the bottom of the Baltic Sea, which provides insight into winemaking practices used at the time. Organic spectroscopy-based nontargeted metabolomics and metallomics give access to the detailed composition of these wines, revealing, for instance, unexpected chemical characteristics in terms of small ion, sugar, and acid contents as well as markers of barrel aging and Maillard reaction products. The distinct aroma composition of these ancient champagne samples, first revealed during tasting sessions, was later confirmed using state-of-the-art aroma analysis techniques. After 170 y of deep sea aging in close-to-perfect conditions, these sleeping champagne bottles awoke to tell us a chapter of the story of winemaking and to reveal their extraordinary archaeometabolome and elemental diversity in the form of chemical signatures related to each individual step of champagne production.