If you brew, or merely enjoy, beer, you may be confident in your ability to detect flavour. But using your senses to check and refine a finished product, or to identify defects and their causes, requires a more rigorous approach. In the first of a series of articles on sensory testing, Will North introduces some of the challenges to establishing a more scientific programme.

For this article, we talked to three experts. Genevieve Upton is a master brewer and beer sommelier, who has worked with Cara Technology since 2024 as customer education lead. Tom Brown is marketing director for FlavorActiV. Cara and FlavorActiV share some roots, but today both offer both stable flavour standards, and training and support services for companies looking to develop or refine sensory testing processes. These flavour standards consist of hundreds of compounds, formulated to be sent out as individual, stable, capsules, often packaged to a specific beer style or tasting task, and used in training.

Phil Douglas is a master brewer, who spent 30 years working with breweries including Scottish & Newcastle, Everards, and Black Sheep. He is now joint managing director of Brewlab, founded in 1986 by Dr Keith Thomas. The company offers a range of services targeting smaller and craft brewers, including training on Professional Flavour Evaluation, either at Brewlab in Sunderland, or at the customers’ brewery. Brewlab provides flavour samples based on specific chemicals in their ‘raw’ state, rather than compounds.

Together, the experts we spoke to identified some key challenges to establishing a sensory testing programme.

Beyond the five basics

At school, we all learn about the five basic flavours: bitter, salty, sour, sweet, and umami. However, the way we perceive flavour is far more complex than this. “People perceive aroma and taste based on individual chemical compounds,” Upton says. “The science is still very much emerging. But we actually know now it’s more like 50 different flavours. We’ve got so many different receptors for all of these individual compounds that are coming into the body. What turns that everyday experience of the world into something measurable is sensory analysis.”

Brewlab focuses on smaller brewers, with introductory classes giving a grounding in the science of taste, and how it can be used in a brewery. “We cover everything from the physiological basis of taste, the theory of tasting, how our body reacts to aromas,”  Douglas says. ”Everything is covered, from raw materials, how they contribute to the flavour of the product, through to how to integrate that into the brewery itself.”

We all taste differently

Science has shown that the building blocks of taste are much more complex than we learned in school. And yet our bodies and minds are capable of incredible discernment. “The human body is amazing for being able to put together these building blocks and create a picture of the product,” Upton says. “[We can detect] compounds at levels that analytically they would barely make a peak on a gas chromatograph, but can have a huge sensory impact.”

As a species, we may beat machines when it comes to sensing flavour. But as individuals, we are all different. “Every person is beautifully unique,” Brown says, “So people will be naturally nose blind to certain flavors.”

Genetic variation has a real impact. Beta-ionone is known to many in the UK as the taste of parma violets. It’s the floral flavour that is integral to a hoppy beer. But, Upton explains, that’s got a 50% anosmia rate: half the population can’t taste it. Similarly, chocolatey and grainy isobutyraldehyde may be missed by a quarter of tasters, and cheesy isovaleric acid, associated with aged hops, may be undetectable by 3% of people.

Brown points out that good panel formation will help account for this. “Get as many people involved as possible,” he says. “Not just brewers or packagers, but people from the warehouse, the sales team, marketing, or finance. You may have a fantastic taster in finance, they don’t have to be brewers.”

Lost in translation

Genetics can mean that each of us can struggle to detect one or another flavour compound. But culture has an impact too. How we describe things shapes how we perceive the world, and our cultural landscape shapes those descriptions. In the UK, we might think of butterscotch when we describe diacetyl; in the US, the reference might be cinema popcorn. But in Eastern Asia, diacetyl might be thought to taste like spoiled rice, Upton explains.

In a later article in this series, we’ll look at how multinational operations can bridge these cultural and linguistic differences.

Context matters

The first step for many brewers entering the world of sensory testing will be as a form of quality control: certain compounds not only show that a beer is off, but can tell a brewer what has gone wrong, either in the brewery or in the supply chain to the customer.

Brown points out this is just a starting point. “We classify flavours in three areas. Attributes may be positive at certain thresholds, but undesirable over another threshold. Defects are naturally occurring flavours that you don’t want in your product. And taints should not occur in any product.”

Some compounds are a positive attribute in one beer, but undesirable elsewhere. “Phenolic is clove-like and aniseedy,” Brown says, “It’s usually undesirable in a lager, but then in a wheat beer, it is more of an attribute.”

A master brewer isn’t a master taster

Historically, master brewers have been seen as something like an alchemist, with supernatural powers across the brewing process. Douglas, a master brewer himself, disputes this. “The head brewer always had the last say. But then if he has an anosmia and couldn’t pick up certain things, then that wouldn’t be picked up within the brewery at all.”

Douglas agrees that the answer is to build a sensory panel that draws from across the brewery. “We focus on really getting out to teams as much as possible.  So not just the brewers, but the sales staff, people in the tap room, they’re really important. It’s about getting the terminology correct, and getting the training in place for as many people as possible.”

Training your senses

Brewlab has helped brewers across the country get started. At the height of the craft brewing boom, the company would regularly have 20 people at a time, looking to get the grounding they needed to set a brewery up. The company then offers ongoing support, helping craft brewers, for example, troubleshoot what might be causing a defect detected in tasting.

FlavorActiV and Cara both work with craft brewers, but also focus on larger and multi-site operations. Here, scale makes it both possible and necessary to adopt a different approach. “The sensory training we deliver is a mix of the theoretical and the practical side, which is where the flavours come in,” Brown says. “You make sure you get the right tasters on a panel, who are motivated and capable. And then bring in a consistent way of identifying flavours that are important to that company.”

At a larger brewery, the programme itself needs to be consistent. “It’s about teaching people to approach it the same way, time and time again,” says Upton, “So that [human testing] is as repeatable as a piece of laboratory equipment.”

This is an ongoing process. How it is carried out will differ depending on the scale of the brewery, whether it is aiming for short runs of unique beers, or a globally consistent product. In the following articles in this series, we’ll look at both these brewery types, and at the challenges posed by customer interest in no and low alcohol beers.