Descriptive Analysis FAQs
Test Planning and Design
My client says I need sensory testing on my product. I’m not sure what that means, can you help me?
What are some of the considerations that must be taken into account when designing a descriptive analysis project?
How do I know whether I should be testing my products with consumers or trained panels?
What if 21st Sensory has never tested a product like mine?
What is a standard panel?
What is the consensus method?
Does 21st Sensory test pharmaceuticals?
How does 21st Sensory test packaging material?
Does 21st Sensory work with any of my competitors?
The Methodology
How do we decide what attributes to evaluate?
What are relational scales?
What are references and how are they used?
What is an intensity reference?
What is a character reference?
What is a lexicon?
What are the 15-point“Universal” scales that are used in food and beverage analysis?
The Panelists
How do panelists learn food descriptive analysis?
How calibrated are the panelists?
If the panelists are so experienced, why do they train so much?
What if the panelists simply don't like my product?
How does 21st Sensory know whether our panelists are doing a good job?
Test Planning and Design
My client says I need sensory testing on my product. I'm not sure what that mean, can you help me?
The term sensory testing can encompass many different types of tests: consumer testing, descriptive analysis, discrimination testing, hedonics, triangle testing, etc. We are happy to work with you to determine the type of test that best meets your objective.
Some products require special protocols, and some are fairly standard. We have project leaders that are particularly skilled at developing the protocol, or method, for testing different types of products.
An example would be quantifying the experience of shaving with an electric shaver. Obviously, you want to know if it does a good job of removing hair or whiskers, but you might also want to know how it feels in your hand and maybe how it sounds. Does the vibration make your hand feel numb; does it emit a high or low pitch? Our project leaders can explore the experience, identify the relevant attributes, and develop scales with which to measure the experience.
Back to Top
What are some of the considerations that must be taken into account when designing a descriptive analysis project?
- Number of different products to be evaluated
- How much test protocol development will be needed
- Number of product attributes to be tested
- Sensory modalities that may include flavor, texture, tactile measures using SkinSensory™,“in the mouth” tests of toothbrushes, or other product dimensions
- Complexity of product and test execution
- Number of panelists involved
- Number of replicates each sample will be tested
- Physical factors which may affect the testing, such as strong tastes or protocols that may require up to 24 hours to normalize senses necessitating long 'rest' times between testing
- Your budget
Once the objective of the test is defined in consultation with the client, and the necessary products are received in our lab, the assigned project leader screens the samples, with the assistance of several additional panelists.
Back to Top
How do I know whether I should be testing my products with consumers or trained panels?
In general, if you want to know how well consumers like your product, or if they can distinguish one product from another, you will ask consumers. If you want an objective measure or comparison of products, or a more robust discrimination test, you will ask trained panelists. We can help you determine which best suits your needs.
Back to Top
What if 21st Sensory has never tested a product like mine?
Our panelists have had experience with many different kinds of products. We have found that once the panelists have been trained to scale attributes, those skills can be applied to new products once they identify the attributes of the product.
Back to Top
What is a standard panel?
Back to Top
What is the consensus method?
Another method we use is the consensus panel method. The orientation, lexicon and ballot development are the same, but a smaller group of panelists participate in the study. Samples are presented in sequential order and balloted individually. After each sample has been evaluated, the project leader writes the scores on a white board. The group reviews the scores and agrees on a score that represents any sensory “space” between attributes.
Clients are invariably amazed at the consistency of the scores between the various panelists. This is attributable to their thorough and uniform training and to the use of well-chosen references with which to compare the product being tested.
Complex? Yes! Involved? Definitely! But at 21st Sensory we have refined this process under the direction of our expert staff to the point that from the arrival of the product in our lab to the submission of the final report, a project can be completed in a surprisingly rapid manner. But at no time is quality ever compromised, and our clients' satisfaction is our ultimate goal. We do whatever it takes!
Back to Top
Does 21st Sensory test pharmaceuticals?
Yes. When testing products that contain active ingredients, an Institutional Review Board (IRB) oversight is required. The IRB is an independent agency of science professionals that reviews the products to be tested and approves appropriate protocols that will protect the health and safety of our panelists during testing.
Back to Top
How does 21st Sensory test packaging material?
If the question is whether or not the packaging imparts a flavor or aroma to food or beverage, the product will be exposed to a model food system, possible water or mineral oil, for a predetermined amount of time. Depending on the intended use, it may be kept in ambient conditions or a heated environment. Then the exposed food item is presented to panelists for assessment.
Sometimes the question is whether or not a container allows flavor to leach from food stored in it. In that case, descriptive analysis may be conducted on a bland food like a pudding that has been stored in the container for a predetermined storage time.
Using ASTM standards and our own experience, we design testing to address the specific objective.
Back to Top
Does 21st Sensory work with any of my competitors?
Relationships with our clients are confidential, so we cannot tell you who our clients are. Our job is to be objective in our work, so whether we work with competitors or not, you will receive our full, unbiased attention when we are working on your project; and your information will also be held in strict confidence.
Back to Top
The Methodology
How do we decide what attributes to evaluate?
Back to Top
What are relational scales?
Scales are relational, that is, they allow us to measure the intensity of unrelated products/attributes with the same scales. This is similar to the concept used when measuring sound in decibels. The sound intensity of a bird's song can be compared to that of an engine because, though the bird and engine are unrelated, the units measuring sound intensity are the same. Similarly, though a feather and rock are unrelated objects, the same scales are used to measure their weight.
In sensory analysis, universal scales are not intrinsic, that is, uniquely associated with only that product. On these scales, a peeled orange has an orange flavor of about 6 or 7, whereas an undiluted orange drink may have a much stronger orange flavor, resulting in a higher intensity score than the 'real' orange.
Universal or relational scales allow us to measure one product's sensory characteristics in relation to the intensity attributes of another product. For example, we can compare the flavor intensity of Kraft medium cheddar, a 6 on the universal scale, in relation to the intensity of the fried potato flavor in a Lay's potato chip. Attributes are scored between 0 and 15 and indicate the intensity of the attribute being considered. This scale is established after an extensive sensory review of products that demonstrate that attribute.
The scale measurements indicate a particular attribute's absence (0) or intensity or magnitude (15 being very intense.)
Back to Top
What are references and how are they used?
In descriptive analysis, the goal is to quantify our observations; that is, to assign intensity scores to the product attributes we are testing. But who's to say we'd score it that way tomorrow? Or that another panelist would not assign a much different score?
The way we handle that is to use references that represent either the character or the intensity of a product’s perceived attributes. These references may be foods, solutions, or other products that have been predetermined to have an intensity or value relative to other products on an external 'universal' scale.
We develop customized references for projects based on published scales or scales we develop that are based on the product category. By having these and many other references available during analysis, panelists are calibrated like analytical instruments and are able to score product attribute intensities using the same 'ruler'.
Back to Top
What is an intensity reference?
An example of an intensity reference would be different saline solutions that represent fixed points on the saltiness scale. Each strength solution has an intensity number. Another example in food descriptive analysis would be the relative intensities of aromatics. For example, the intensity of the grape flavor in Welch's grape juice is a '10.0' and the cooked apple flavor in Mott's apple sauce is a '5.0'.
Back to Top
What is a character reference?
Character references are products that have some of the same attributes as the products being tested. They are used to standardize the vocabulary so the panelists can agree on the terms they are going to use and to be sure they are all measuring the same thing. In some cases, they will also agree on intensity numbers for some of the attributes of the character reference. Those assigned numbers will be in relation to the intensity of the basic taste solution.
Back to Top
>What is a lexicon?
A lexicon is a specialized dictionary of terms used for a specific purpose. In our work, each descriptive analysis project has its own lexicon of terms which are the attributes measured for that project. The definitions are given in terms relevant to the project, and references and examples are often included.
Consider, for example, if you were to ask a group of people to feel the surface of a flower, say, a freshly picked rose. They might come up with words like soft, moist, silky, bumpy, folded, powdery, thick, thin, smooth, pliable, ridged and many others. After discussion, you may discover that several are using ridged, bumpy, and folded interchangeably. Others may use silky and soft interchangeably while still others vehemently feel that silky and soft have different meanings.
When panelists begin a new project, the panelists meet and do their own screening of the samples. They pool all of their observations about the products' characteristics.
From these observations, they draft a ballot with a precise lexicon. They agree on the definitions and examples of each term and benchmarks that calibrate them to the different degrees of magnitude of the terms. This ensures that all of the panelists 'file' their observations in a uniform manner on the ballot.
Back to Top
What are the 15-point Universal; scales that are used in food and beverage analysis?
The 15-point Universal Scale is an industry standard in food and beverage sensory descriptive analysis. Its usefulness has been proven through many years of experience. It is a relational scale, so that varied products can be compared to each other as they are all rated on the same scale.
Using these scales, manufacturers, product developers, quality control and sensory scientists can communicate about the qualitative and quantitative characteristics about products globally.
Back to Top
The Panelists
How do panelists learn food descriptive analysis?
It's like learning music. Remember the first time you heard an orchestra play a 40 minute symphony? It was a wall of integrated sound. If you kept listening, you began distinguishing the unique voices of individual instruments, melodies and the rhythm. When you became very familiar with the piece, you could tell whether the orchestra was balanced, on pitch and on beat. This is very much like learning to be a descriptive panelist.
Potential panelists must pass a battery of taste tests, scaling exercises and interviews. Then, they begin a 150 hour training and internship program in which they learn to dissect flavor and food texture, to measure the intensity of sensory experiences and to utilize "Universal" scales. Like hearing a symphony for the first time, trainees are initially overwhelmed by the complexity of their task. However, with practice and repetition, trainees soon learn the components of individual products.
Back to Top
How calibrated are the panelists?
Data from our highly trained panelists will often demonstrate statistically significant differences between means of 0.2 to 0.4 on a 15 point scale. While these are generally not perceptible to the consumer, it demonstrates how highly calibratedthe panelists are (Panelists train at least 100 hours to learn this stuff. Iat's hard to be thorough in 25 words or less!)
Back to Top
If the panelists are so experienced, why do they train so much?
An important part of every project’s orientation phase is panel training. This may sound strange when one considers the hundreds if not thousands of hours of prior experience and training each of our panelists has accumulated. However, for each and every project, panelists explore and learn the nuances of the sample and references set. In this way, the panel's consistency and quality is maintained and assured.
We think of the panelists’ ongoing training as similar to the orchestra practicing a piece of music. While the piece may be familiar, it is important to re-familiarize oneself with the tempo and review the complexities of the music before actually playing it “for real”.
Back to Top
What if the panelists simply don't like my product?
The work done by our trained panels is strictly objective. The first thing they learnwhen they begin training is that their opinion is irrelevant and it is not appropriate to express an opinion (like or dislike) when they are evaluating products.
Additionally, care is taken to avoid any bias that may result from brand association. All samples that go into the panel room are identified only by a random, three-digit code. Many of the products we test are prototypes, so the panelists will not have had a prior association; but any mark that would identify the product by brand or company is removed. We also take care to avoid mentioning client company names to the panel. The focus is strictly on the samples before them.
Back to Top
How does 21st Sensory know whether panelists are doing a good job?
Our panel manager regularly reviews data and monitors the work. A couple of times a year she meets individually with each panelist after reviewing their data in relation to the rest of the group, and individual performance on designed tests.