Goal of this sensory wheelThe goal of this tutorial is to re-build the classic version of the coffee tasters’ sensory wheel displayed in this article from coffeeandhealth.org, based on the different attributes stored in an Excel spreadsheet. Once it is drawn, a sensory wheel is very useful to help characterize a specific product with different levels of precision.
Dataset for drawing a sensory wheel in ExcelAn Excel workbook with both the data and the results can be downloaded by clicking on the button below:
Download the data
The data used are the attributes that can be seen in this article which displays the Coffee Flavour Wheel Adapted from that of the Specialty Coffee Association of America.
The data is available in two different formats, that can both be introduced as an input in the XLSTAT sensory wheel feature:
- The List of Words format. This format only includes the 34 most specific attributes, which are the ones that will be displayed the farthest from the center of the wheel. This format requires that the user manually edits the lower levels of the sensory wheel once it is drawn.
- The Classification table format. This format displays the different levels of attributes, from the most general (level 1) to the most specific (level 4). This format automatically provides a sensory wheel with a typical nested structure.
Drawing a sensory using the List of Words data formatOnce XLSTAT is open, select the XLSTAT / Sensory Data Analysis / Sensory wheel command as shown below.
The Sensory wheel dialog box appears.
Activate the List of Words format then select the corresponding data under the Words table.
In the options tab, set the number of levels at 4.
Click on OK. The sensory wheel appears.
Each slice from the center to the outer circle is linked to one single attribute and is divided into 4 levels.
It is then possible to manually edit the lower levels of the wheel so that it reaches the desired hierarchical structure. For instance, let’s merge floral and fragrent into flowery at level 3. Click anywhere on the wheel.
You may receive a message asking you if you want to trust the XLSTAT-MXM.dll file. If this occurs, click yes.
The below dialog box appears. Fill it in as indicated below:
Click on Apply then Close. You can see the resulting merge in the image below:
Now we switch to drawing the sensory wheel from a more complete dataset in the form of a classification table.
Drawing a sensory wheel using the Classification table formatGo back to the XLSTAT / Sensory Data Analysis / Sensory wheel command and fill out the general dialog box as follows:
Interpreting a sensory wheelThe complete sensory wheel with its nested structure appears.
It can be used by coffee tasters who will be able to characterize coffee samples at different levels of specificity, going from the center to the outer part of the wheel.
This article gives more hints on the interpretation of a sensory wheel.
PS: Section widths can be controlled using an additional column of frequencies that should be introduced in the general tab of the dialog box.