Tea Infuser for Loose Leaf Tea

Sheng pu erh gets bitter if brewed too long, but shou put erh doesn't. I recently thermos brewed some shou for a hike. At the end of my 6 hour hike, so about 7 hours after putting it in my thermos and pouring boiling water on it, it had some slight bitterness to it so I drank the rest of it with a tea spoon of maple syrup added to it. If you want to brew gong fu style - or even Western style for that matter - at work without lots of gear I'd probably get something like this all in one glass pot, or this which is basically just the pot part that you can put directly on a big mug to decant.