Quora is a crowd-sourced website helpful in resolving pressing matters like global warfare, climate change and whether dunking offers a distinct advantage over those who patiently wait while steeping. It was recently awarded $80 million in funding and now has answers to hundreds of thousands of questions.
Matt Harbowy, a chemist pursuing the great questions of our day, decided to put to test the dunker’s hypothesis. His study silences the myth that dunking reduces steeping time or produces a richer cup of cuppa.
“This is a fairly complicated question to answer, one which I spent a considerable amount of time researching about 15 or so years ago,” writes Harbowy.
Here is his explanation: “Tea bags largely obey first order kinetics, so the rate of dissolution slows down as the concentration of tea rises. This is governed by the Noyes-Whitney equation
Tea contains a series of layers- the boundary of the leaf and the boundary of the tea bag both matter. If Cb, the concentration in bulk solution, approximately equals Cs, the concentration at the surface, dunking would impact the rate of diffusion.
“At the instant you dip the teabag, there is no water inside the bag. This is the first problem- the tea bag material is porous, but is also relatively hydrophobic, so it takes a bit of time and energy for water to diffuse across the boundary of the bag. Different papers have different wetting coefficients, and this is the first reason you might want to “dunk” the tea bag- to encourage water to enter the bag,” writes Harbowy.
“Within statistical error, under almost all testing conditions, I cannot find a difference between dunking and not dunking under controlled circumstances, so do it how you want. There is almost as much statistical noise in the wettability of the paper and the leaf from one bag to the next as there is in dissolution rates, and small changes in manufacture usually matter more than anything else the consumer on the teabag side can control,” writes Harbowy.
He explains that “dunking gives you something to do. As with “a watched pot never boils”, the perception of time decreases if you are dunking versus watching it float.”
Why does dunking seem to impact the color, then?
“It doesn’t. If you let the bag steep idle, the tea will diffuse into solution around the bag, and a quick swirl will darken the rest of the cup to approximately the same level as constant dunking,” writes Harbowy.
What does matter? Adding milk first coats the surface of the teabag with fats that inhibit infusion. So whether you dunk or patiently wait for your tea to steep, remember to pour the milk in last.
Learn more at Tea Dunking a British website created to promote National Biscuit Dunking Day.