The Soft Science of Sensory Perception

By Keith Lemcke
November 02, 2022

In summer of 2022, our Siebel Institute research brewer created two batches of beer as part of a project to develop a new beer recipe. The two batches were practically identical in their formulas and methods of production, but they had one glaringly notable difference, namely in their bitterness. In the finished versions, beer #1 had measured bitterness of 33 BU’s while beer #2 had 25 BU’s. With our trained tasters, we agreed that this was easy to spot, and that there were very few other differences. However, we then conducted taste panels asking about 270 tasters, mostly average beer consumers, which of the beers they preferred. Many of the tasters also offered comments on characteristics of the beers that were in some cases quite surprising.

One trend among respondents was to label beer #2 as being more bitter or more dry, which was quite the opposite of what the majority of tasters perceived, especially given the decidedly higher tested bitterness of beer #1, a beer which was on the edge of being overly bitter. Bitterness and sweetness are usually something on which most tasters agree, so finding so many “outliers” on these basic tastes was something of an eye-opener.

A more common issue is the capacity of people to find characteristic differences between samples that aren’t really there, or in most case, aren’t perceivable to most tasters. Both of the beers were very straightforward pilsner-style brews, with aromas dominated by graininess, a bit of fruity esters, and slight corn aromas (DMS, for those who know brewing aromas) from the grains. However, comments from tasters included flavors of butter, tannins, vanilla, sourness and a claim that one of the beers was “watery”. It could be that the people perceiving these compounds are “hyper-sensitive” to these specific flavors and aromas and that the compounds truly are present in the beer, but it could also be true that the taster is simply incorrect.

A lot can be gained from the results of taste panels like this, not just in assessing the products but in understanding people. Breweries that conduct taste panels need to be aware of the variability and fallibility of human tasters, and that needs to be taken into account when asking their employees to be part of a taste panel program. Well-trained taste panel managers are acutely aware of the failings of human tasters, yet humans are still incredibly important to maintaining beer quality through tasting programs. The best way to assure that the results coming back from taste panels retains accuracy is by training tasters using methods designed by groups like the American Society of Brewing Chemists (ASBC) as well as other sensory training specialists.

Offering regular training using sensory training kits isn’t difficult, yet it can be time-consuming to set up, and especially to record and analyze panel results. The majority of breweries don’t have the training nor staffing required to run a full-scale, data-driven sensory panel program, yet it shouldn’t stop the brewery from offering basic sensory training. Setting up sensory training on a regularly occurring schedule can be done simply by using pitchers of beer prepared with “spikes” from a sensory kit, allowing staff to sample beer as their time permits during breaks or at the end of the work day. The Siebel Institute Sensory Station channel on YouTube offers fully narrated videos regarding sample preparation, tasting and experiencing the range of flavors and aromas found in the Siebel sensory kits, helping any brewery to train staff to overcome “the human factor” of sensory towards building professional-level tasting skills. If you want to improve the accuracy of brewery taste panel results, frequent sensory training just makes… sense.

Go to the Siebel Institute Sensory Station Channel on YouTube at