Does anybody know...?
JT and I were battling with a question earlier... Why do teabags inflate when you pour boiling water on them? Now usually when I have little moments of trivial intrigue like this, I go to JT and ask him, because he generally knows everything - he's especially good with definitions and how things work. However when he didn't know the answer to this taxing little issue, I knew that it must be a serious matter. Does anyone else know? I didn't like to ask before in case I sounded blonde...
posted by NaiT at 1:55 PM
5 Comments:
I think its because the dry tea leaves become hydrated and expand? Maybe the paper also does and because its suddenly under water, any air in the teabag behaves like a bubble.
Professor Hoggstar
I wondered about this, but you'd have thougt that, being a mesh, the air might escape? Hmmmm.... Tricky!
My theory is the air inside the teabag suddenly heats up. When air heats up it expands thus 'inflating' the teabag.
But... It's a mesh!!
When the boiling water hits the tea leaves, it is soaked up inside the bag, still releasing large quantities of steam. Of course this does eventually leave through the holes but the volume generated is so large that the pressure of steam increases inside the bag while steam molecules are fighting for the available exits. Once the pressure reaches a certain point, the speed of release increases letting more molecules out of the holes and a balance occurs rather than the tea bag ripping as would be the case if it had no holes in it at all. Elementary my dear Naomi.
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