You may have already seen the triangle test in practice, as it is used in cupping championships: participants are presented with 3 coffees and have to push the coffee that differs from the other two to the front.
But is a triangle test also suitable for other situations?
And what are the differences with the in/out test?
This article will help you,
- sort both tests into sensory testing schemes,
- understand each test and its function
- and learn about the advantages and disadvantages.
Finally, you'll get 8 valuable tips if you want to get started right away.
Wanted: General differences
Both tests, the Triangle Test and the In/Out Test, are methods of so-called difference or discrimination testing. What does this mean? Let's imagine we want to roast a similar product to that of a successful competitor. To do this, we take our coffee, which we believe is close to the competitor's product. We check if there are any differences in general between our coffee and the coffee of a competitor.
Uninteresting: the detail
Both tests are about looking at the product holistically, in this case here: our coffee.
The counterpart to this are tests that compare product samples only and exclusively for a specific characteristic. For example, which coffee brings more sweetness or acidity.
In sensory terms, these tests are called "methods for determining characteristic-related product differences."
Back to our tests and the holistic approach. In addition to the triangle and in/out tests, there are a number of other tests using this method. However, we do not want to go into that here, but it should still be mentioned, I think.
6 situations for a triangle test
We have just seen one situation in which we can use the triangle or in/out test: We want to roast a similar coffee product to that of our competitor. But there are other situations:
We want to reduce the cost of a coffee product by reducing the proportion of one coffee in a blend or replacing it with another. Our product should not suffer any noticeable loss of flavor in the process.
Or we have a filter coffee that doesn't resonate with consumers. By changing the recipe, can we give the coffee a new direction and make it attractive to other target groups or preparation methods?
We want to roast a similar coffee product to that of our competitor (explained above)
We plan to give our coffee to a consumer panel for tasting to determine preferences and acceptance. A pre-test will show us if our products can be differentiated at all.
We want to introduce new packaging. How do the characteristics of the new packaging compare to those of our current packaging when we think about freshness , aroma and taste?
Our coffees are to be stored differently: Does the new storage location affect the sensory characteristics of our coffee, or do the coffees taste the same untouched?
So what happens in a triangle test?
We test three coffees, two of which are the same, the other deviates. Our task is to find the coffee that deviates. Because we taste all three coffees against each other, this test is also called a triangle test. We'll get to the pros and cons of this test in a moment.
And what happens in an in/out test?
Let's take a look at the In/Out test. Again, we test three coffees, but one of them is labeled as the reference coffee. Of the other two coffees, one is identical to our reference coffee. Our task now is to find out which one it is. To do this, we start with the reference sample. In the In/Out test, we can still vary whether we always take the same coffee as the reference, or whether we want to use both coffees alternately as the reference coffee.
Both tests differ in these two characteristics:
First, in the number of comparisons: In the Triangle test, we make three comparisons between the coffees. In the In/Out test, we compare only two coffees.
Second, in the guessing probability: In the triangle test, there is a 1 in 3 chance that we will find the coffee that differs by guessing. In the in/out test, the chance is 1 in 2.
The beauty of the triangle test:
It is very easy to perform. This type of test is the most widely used sensory testing method in Germany. However, we also receive only limited statements or information about the coffees:
(a) the differences between the coffees are significant,
(b) they are not significant, and
(c) the coffees are similar or not.
Also pleasant is the low "I'm guessing" probability of 1 in 3.
The beauty of the In/Out test:
I can specify a reference coffee and thus specify an exact sequence of tasting.
In addition, I may have less effort, since I only have to taste twice, and I am finished with my test series faster, so I need less time overall.
Unfortunately, I have to keep in mind that there is a high "I'm guessing" probability, especially when the differences in the coffees are not very large.
8 Tips for Successful Testing - No matter if you hear triangle test or in/out test.
Now you know what it's all about when you hear triangle test and in/out test. If you want to get started yourself, you will now receive some valuable tips:
- If you want to get statistically reliable results, check the number of tests and the number of examiners (cuppers) before you start. For triangular tests, a number of 12 to 18 examiners can be reached quickly, depending on the differences in the coffee. DIN/ISO 4120 and DIN 10 971 for the in/out test (duo-trio test) provide more detailed regulations.
- All coffees must have the same temperature.
- The amount of coffee must be the same in all samples.
- Ideally, you use bowls whose inside is dark so that no conclusions can be drawn from the color of the coffee grounds.
- Give each coffee sample at least a three-digit code, i.e. an arbitrary sequence of numbers. The brain has a hard time with arbitrary and non-systematic number sequences starting with three numbers. This prevents you and your examiners from recognizing or assigning coffees.
- Before the test, think carefully about how to arrange the samples.
- If you want to practice for yourself to improve your sensory skills, ask a colleague to help you.
- Prepare a result sheet on which you note or mark your results of the tasting.