Talk like an analytical chemist

Brewing — the process of producing beer, which involves soaking malt in water to release sugars, followed by fermentation to produce alcohol

Fermentation — the process by which, during brewing, enzymes in yeast convert sugar (glucose) into alcohol (ethanol) and carbon dioxide: C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂

Hop — a flower from the hemp family of plants, used to give flavour, aroma and bitterness to beer

Liquid chromatography — an analytical technique to separate a complex liquid solution into its chemical components

Malt — a cereal grain (most commonly barley) that has been soaked in water to begin germination, then dried to prevent further germination

Mass spectrometry — an analytical technique to identify chemical compounds in a sample 

Humans have been drinking beer for thousands of years. The world’s first beer recipe is found in an ancient prayer to Ninkasi, the goddess of beer, worshiped by inhabitants of ancient Mesopotamia. Workers building the Pyramids of Giza in ancient Egypt were given a daily ration of beer to keep them refreshed and hydrated. And beer is still important today. In 2019, the beer industry supported over 23 million jobs around the world and contributed $555 billion to the global economy. In many countries, beer is not only an integral part of society, but a source of national pride. From Heineken in the Netherlands to Guiness in Ireland, each beer has its own unique identity and flavour.

At Christopher Newport University, Dr Ron Quinlan is leading a team of analytical chemists and commercial brewers to uncover the chemical composition of beer. He hopes that by understanding how environmental conditions impact the chemistry of beer ingredients, brewers will have more control over the taste of their beers.

What is beer made from?

“Beer contains four key ingredients: malt, hops, yeast and water,” explains Kevin Kingsbury, Head Brewer at Tradition Brewing. Malt and hops contribute to the beer’s flavour, as well as providing health benefits due to the vitamins, essential oils and acids they contain. “Different combinations of these compounds can lead to designed changes in the beer’s bitterness, aroma and taste,” explains Kevin. Malt also creates the beer’s colour and provides the sugars which the yeast converts into alcohol during fermentation.

How do environmental conditions influence the taste of beer?

A beer’s flavour is dependent on its ingredients and the brewing process, thanks to the chemistry of the malt, hops and water, and the chemical changes that occur during fermentation. Most of a beer’s volume is water, so local water chemistry influences the beer’s taste. The specific chemical compounds found in malt and hops depend on the environment in which they are grown. “Changing the environmental conditions changes the chemical ratios within the same plant species,” explains Ron. “And changing the ratios of the chemicals in beer results in changes in the flavour.”

As climate change causes environmental conditions to change, brewers around the world will have to adapt if they are to preserve their signature tastes. “This research is exciting because we’re just beginning to understand how the growing environment of malt and hops influences the flavour of beer,” says Ron.

How is the team chemically analysing beer?

Ron and the team are combining two analytical techniques, liquid chromatography and mass spectrometry, to determine the chemical composition of beer and beer ingredients. Liquid chromatography separates a sample into its chemical components, then mass spectrometry analyses each individual component and identifies what chemical compounds it contains. “When we put the two techniques together, we can determine which compounds are present in the beer with very high accuracy and precision,” explains Celina Paoletta, a student in Ron’s lab.

The team uses these techniques to determine which compounds are produced by the hops and malt before they go into the beer. “We then track the compounds through the brewing process and into the finished beer,” says Chris Balog, another student. “This allows us to discover previously unidentified chemical reactions taking place during the brewing process.”

Through this research project, Ron is keen to highlight the real-world applications of analytical chemistry. “It’s easy for analytical chemists to get caught up in their lab-based methods,” he explains. “Collaborating with industry partners, like Tradition Brewing, means we are working on research that has an impact on society.” This partnership also means students gain practical experience of applying their analytical chemistry knowledge to address real-world challenges in a fun and engaging project.

What has the team discovered?

So far, the team has observed that hops and malt grown in different environments have different ratios of chemical compounds. “For example, if the same species of hop is grown in the US and Europe, each plant will contain the same types of compounds but in different concentrations,” says Ron. He is now trying to determine how chemical reactions during the brewing process cause these changes. Kevin explains, “What we do know is that growing the same species of hop in different environments, then brewing them with the same recipe into beer, will result in slightly different beer chemistry and, therefore, different tastes.”

How will this research impact the beer industry?

By understanding exactly how environmental conditions influence the chemistry of hops and malt, the team hopes that farmers will be able to grow hops and malt with specific chemical profiles, while tailoring their agricultural practices to be more efficient. Brewers could then brew these hops and malt into new beers with specific tastes or health benefits. For example, some chemical compounds are thought to help protect against cancer. If hops and malt could be grown to contain these compounds, they could be brewed into beers with targeted health benefits.

As climate change continues to impact food supplies, Ron, Kevin, Celina and Chris are ensuring that brewers will continue to brew tasty beer that contributes to a huge global industry.

Dr Ron Quinlan
Department of Molecular Biology and Chemistry, Christopher Newport University, USA

Field of research: Analytical chemistry

Research project: Analysing the chemistry of beer

Funder: US National Science Foundation (NSF)

About analytical chemistry

“According to the chemist, C.N. Reilly, analytical chemistry is what analytical chemists do,” jokes Ron. “In fact, analytical chemistry is the study of how matter interacts and behaves as it is undergoing chemical analysis.” Here, Ron is pointing out the subtle difference between analytical chemistry and chemical analysis. While chemical analysis aims to determine what matter is made up of, analytical chemistry is focused on the methods that are used to do this, such as liquid chromatography and mass spectrometry. “Analytical chemists seek to find and correct errors in current methods of analysing chemical compounds, and to discover new analytical chemistry techniques,” explains Ron.

What skills do analytical chemists need?

Patience is a key skill for analytical chemists. “We constantly reanalyse the same sample with small changes in the method,” says Ron. This might mean repeating an analysis multiple times with slightly different volumes of the sample to discover how this impacts the results, or performing the same analysis again and again to calculate the reproducibility of the method. Therefore, analytical chemists must also have good attention to detail and an ability to work precisely and accurately.

What are the joys of analytical chemistry?

“Analytical chemistry is applicable to every other science,” says Ron. “Do you want to study organic chemistry, pharmaceuticals, cellular metabolism or neurological disorders? For all of these, you need an analytical chemist to make your measurements.”

“I enjoy the complexity and attention to detail that is inherent in analytical chemistry,” says Celina. “Studying analytical chemistry fosters critical thinking and problem-solving skills. It also teaches you how to ask better questions and how to fail forward, and you get to learn more about the world in the process.”