If your tea is lukewarm by the time you’ve scraped the ice off the windscreen, it’s the mug that’s the problem, not your tea. Most cheap travel mugs leak heat through the lid, and some of them leak tea too.
The one I’d buy is the Zojirushi SM-SA60 stainless steel mug. It’s a 20oz (about 600ml) vacuum-insulated flask-style mug from a Japanese brand that’s been making flasks and rice cookers for decades.
How hot, and for how long?
It’s double-walled stainless steel with a vacuum in between. Zojirushi say the tight flip-open lid holds heat better than a typical travel mug, and the lid is where most mugs lose it. They don’t promise a set number of hours on the listing, just “hours”, so I won’t either. Fill it with properly hot tea and it’ll still be hot when you get to work.
Will it leak in my bag?
There’s a lock on the lid so it can’t flip open by accident. It’s a sealed flask, not a coffee-shop cup with a sip hole. The lid opens in two steps, releasing first and then flipping, so any drips on the seal fall back into the mug instead of over your hand.
Is it a pain to clean?
This is the bit people worry about with good flasks, and it’s fair. The inside has a non-stick coating so tea stains don’t build up as much, and the lid comes completely apart, gasket and all. That means you can actually get it clean, but it also means a few small parts to wash and put back. I’d wash it by hand.
Anything I wouldn’t like?
You drink straight from the spout, which has a small air vent so it pours smoothly, but it’s narrower than a mug rim. If you like to wrap your hands round a wide cup it’ll feel more like a flask than a mug. It’s also slim and tall rather than squat, so check it fits your car’s cup holder.
For a cold walk to the station or a long day on site, though, it’s the one I’d pick.
