Case ExampleTaste Watch January 2011

Taste Watch is a condensed one page length report with colorful graphs and charts focusing on various food/beverage categories. The report provides alternate view regarding taste and examples of how to use analyzed taste data.

Bottled Green Tea

Change in Taste Quality Over Time : Bottled Green Tea

Expiration date of a food or beverage product provides guideline for its quality for consumption. When it comes to taste, however, is considered one of the difficult areas to show whether a product's taste quality is maintained until its expiration date. In this report, 12-month taste data of a bottled green tea product is recorded to see whether change in taste over time can be observed in numerical value, which will provide new and accurate method to calculate its expiration date.

Gradual Change in Taste

A bottled green tea product "Oi Ocha" by ITO EN Inc. is used as a sample. Several samples were stored in a locker in standard room temperature and opened on scheduled date. The sample's expiration date is labeled 6 months after production. The data collected includes 4, 6, 8, 10, and 12 months after production.

Figure 1 is a scatter plot using "Umami (foretaste)," a lingering rich taste, and "Briskness" as axes. Compared to the product's average taste quality, 4 months after production shows decline in both "Umami" and "Briskness." No large difference is found between 4 months and 6 months. However, 8 months shows even more decline in "Umami." 12 months after production (6 months past expiration date) shows very low "Umami" and "Briskness."

Figure 1Umami & Briskness
Figure 2Taste Balance Change

Figure 2 shows radar charts with additional taste axes. Average taste quality is used as a control.


The sample 4 months after production shows some increase in "Sourness."


After 8 months, taste balance changes and there are increase in "Bitterness" and decrease in "Umami (foretaste)."


The balance does not resemble the control after 12 months, with strong "Sourness" and "Bitterness." Also, "Umami (fore and aftertaste)" and "Briskness" are low, creating brassy and dull tasting tea.


From observing the sample's taste change data, 6 months expiration date label is accurate since the data shows the taste changes greatly between 6 to 8 months after production.