Hedonic Testing: Gauging the Liking of Spirits

Craft distillers often have strong ideas about the products they want to make and how those products should taste. Yet there is great value in measuring how much consumers like a product—and that liking is a thing that can be measured and analyzed.

In previous articles, we’ve touched on evaluator recruitment, the statistics of sensory science, and discriminative testing. In this one, we take a closer look at hedonic testing and its uses in the beverage industry.

What Is Hedonic Testing?

In sensory science, we use the term “hedonic” for testing that’s designed to measure how much a consumer likes something. Hedonic tests can measure enjoyment of specific aspects of a product or of the product as a whole. Producers often perform these tests when they are creating new products or altering existing ones to better suit the current market.

There are many different ways to conduct hedonic testing, but in distilling and the wider beverage industry, the most common and simple method is to have consumers taste samples of the products in question and then ask them to rate them using a decided-upon scale. The producer can then analyze the ratings to determine which products have the highest and lowest hedonic scores and then make decisions based on these scores.

While hedonic testing is relatively easy to conduct, there are some important factors and limitations that sensory scientists should understand before they begin testing.

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The Nine-Point Hedonic Scale

The first thing to consider is what kind of scale to use for the hedonic testing. There are many scales that can be used to measure the liking of something; by far the most popular for food and beverage is the nine-point hedonic scale.

Initially created by the University of Chicago for the U.S. military to test army rations, the nine-point hedonic scale is a categorical scale that asks consumers to rank products based on nine terms that describe their attitude toward the products. These rankings can then be converted into numerical scores that can be further interpreted by parametric statistics.

While the nine-point hedonic scale is the standard for use in food and beverage, its popularity has spread to many other kinds of products. It is now commonly used in the cosmetic, personal-care, and even household-product industries. Partly, this is because the nine-point scale has more intervals (or options) than other traditional hedonic scales, thus giving it more discriminatory power and increasing its accuracy.

Another factor increasing the discriminatory power of the nine-point hedonic scale is that the verbal anchors used for each rank have been specially selected to be nondescriptive. This is important because descriptive words can carry great ambiguity among consumers and can change how consumers perceive their liking of something. Furthermore, the modifier words in each rank also have been selected for their equal psychological interval from one another. The term “like moderately” is considered to have the same psychological distances from both “like slightly” and “like very much.” That makes it simpler to assign sequential scores to each rank, and it’s easier to analyze the data using standard statistics.

Although the nine-point hedonic scale is considered the gold standard scale for hedonic testing, it does have some difficulties. Most notably, the scale is vulnerable to the error of central-tendency bias. This is a psychological bias that makes consumers reluctant to use the extremes of any scale; thus, it reduces the number of possible answers. In addition, consumers will sometimes use the neutral value—neither like nor dislike—as a dump score for samples that they don’t like but don’t wish to rate poorly. This can further limit the range of useful answers.

Over the years, there have been several expansions and proposed changes to try to improve the nine-point hedonic scale. Some sensory scientists believe that the scale should be expanded to 11 points or that the neutral category should be removed to control some of the aforementioned problems. However, few organizations have adopted these recommendations.

There also have been a few tests aimed at determining whether there is a difference in discriminatory ability when presenting the scale either horizontally or vertically. So far, it appears that there is no major difference between presentations; however, if you are conducting hedonic testing with the scale across multiple products, it’s best if the presentation remains consistent.

Limitations of Hedonic Testing

It’s also important to understand some of the inherent limitations of hedonic testing.

The first limitation is that it shouldn’t be used as a replacement for, or even in conjunction with, descriptive testing. The purpose of hedonic testing is to determine a consumer’s level of liking of a product, not to have them describe the product. While hedonic questionnaires can include questions about consumer feelings on specific attributes of a product, it’s important that the questions not get too technical or descriptive. Consumers are often unsure of the exact reason they like specific products at all; asking them to give descriptors can alter their perceived enjoyment of a product.

A second limitation of hedonic testing is that it can be greatly influenced by context bias. Context bias is the term sensory scientists use to describe bias that is inherent to a situation or place. Context bias can come from the physical features of a place, the current social attitudes of testers, or even the weather. This bias can greatly affect the results of a hedonic test. For example, many people will respond more positively on hedonic testing to warm drinks when it is snowing outside than when it is sunny. This means that sensory scientists must take great care to minimize and account for contextual bias before interpreting the results of any hedonic testing.

The final and perhaps foremost limitation of hedonic testing is that, although it can tell a producer how much a consumer likes a product, it has no way of determining whether that product will be successful. Throughout the history of sensory science, there are many products that have ranked highly in hedonic testing but have gone on to be complete flops in the market.

Part of the reason hedonic testing can’t predict successful products is that it doesn’t have any way to measure how often a consumer will buy a product they like or how much of the product they will buy.

For example, let’s say an established bakery decides to revamp its menu and create new recipes for some of their existing products. They conduct hedonic testing with their customers, and they determine that their new Black Forest cake has by far the highest hedonic score among all their menu items. Should they then drop everything to focus solely on Black Forest cake? The answer, of course, is no! Although the Black Forest cake may have scored well hedonically, there are many other factors that go into making menu decisions, and it’s doubtful that customers will be eating enough cake to keep the business afloat.

It's important to keep in mind that positive hedonic tests are only one aspect of a successful product and that there is more in the market to consider.

One Tool Among Many

Hedonic testing can be incredibly important for companies large and small. For craft distillers, it can help you learn about and understand consumers’ preferences for your own products as well as others in the marketplace. That knowledge is especially useful when you are trying to create new products or revamp older ones.

Many beverage companies even require newly developed products to have a minimum hedonic score before they consider releasing them to the public. These requirements help to keep companies from wasting time and resources on products that will not be accepted by consumers, helping to ensure profitability.

Still, it’s always important to remember that hedonic testing has limitations. While it can tell you how much consumers enjoy a product, it is not—in and of itself—a valid predictor for success.