Do you follow a ritual every time you make tea? Always heat water on the same burner, pour it into the same cup, steep your tea bag for exactly the same amount of time? Or do you prefer to constantly dip your tea bag in the cup, thinking that the bouncing motion encourages the tea to diffuse more quickly or produce a stronger cup? If so, tea chemist Matt Harbowy has a rude awakening for you: bouncing a tea bag doesn't do a thing.
Harbowy explains that tea diffusion has more to do with the material of the bag and the type of tea leaf within than the way the tea is dunked. "Within statistical error, under almost all circumstances, I cannot find a difference between dunking and not dunking under controlled circumstances," he writes. He also has an easy explanation for why some tea drinkers may stubbornly believe that bouncing their tea bag in the cup has some impact on flavor or diffusion speed:
"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."
Instead of leaving the topic with that simple explanation, Harbowy also provides a great explanation of the factors that do affect tea diffusion. Some factors are impossible to predict. As tea leaves are dried, they lose moisture, and the drier a leaf is, the longer it takes to absorb water. That makes for a slower brew. Tea from the same plant won't be uniformly dried. The cut of the leaf matters, too, which is why Crush, Tear, Curl tea is processed to crush the leaf's waxy exterior. This minimizes the leaf's hydrophobic properties and leads to faster water absorption.
Harbowy also goes on to defend tea bags, which are often looked down upon compared to loose tea.
He writes that freshness is important, and tea bags have gotten a bad rap because they're often left in drawers to grow stale. CTC leaves don't deserve the criticism they receive, either:
"It's also a myth that CTC=teabag tea=cheaper. CTC is actually fairly intensive compared with automated, orthodox-style knives. CTC was developed to reduce the significant, back-breaking labor of getting a uniform crush on the leaves after withering, because the tea would not be red if the portion of the cell that contains the catechins, and the portion of the cell that contains polyphenol oxidase, couldn't be opened up and combined. Orthodox manufacture tends to produce a lighter, more yellowish tea, whereas deeper red brews are generally more preferred by most tea drinkers, particularly when adding milk."
Not all tea bags are quite created equal, though. Harbowy says to beware pillow bags:
"Tea leaves do swell in hot water. If you don't allow the tea bag to expand with it, you will reduce A (inside the leaf) in the Noyes Whitney equation, and the rate of dissolution will be lower. However, both Pyramidal and Constanta (pic above) bags perform nearly identically, and "pillow" bags perform noticeably poorer (except with fine "dust" grade tea), when using CTC or broken orthodox leaf. Orange Pekoe and larger sizing tends to perform better in a Pyramidal bag."
But whatever kind of tea bags you use, you can bounce or not bounce as you please. If you notice a difference, it's all in your mind.