The market is brimming with newfangled thermal tumblers that promise a better, more ergonomically graspable hot drink on the go. But the majority are made of stainless steel or some plastic composite, which can spoil the taste, and I can't wrap my lips around the invariably thick rims of the containers or the slats in lids that seem downright unwelcoming to the shape of the human mouth.
Thankfully, I have discovered the sipper-friendly, tough, double-wall Borosilicate Glass Tea Tumbler from Sun's Tea. The 18-ounce cylinder (which is great for any beverage) is a comfortable grab, and the rim feels made for lips. The twist on/off thermal lid seals airtight. There's no drinking slat; you'll have to brave the open container when you want a sip — but it's tall and slim and deep enough to avoid slopping over as it nests in a cup holder. The tumbler comes with a slim removable stainless steel strainer that settles into a niche near the top, so you can use loose tea leaves, other herbs, very coarsely ground coffee beans, or even pieces of fruit for flavor. Borosilicate glass is a lead-free, heat-resistant invention (the outside of the container won't feel hot or cold) that looks and feels just like glass but is infinitely less fragile (though not unbreakable) and is microwave- and dishwasher-safe. I like seeing the steeping tea leaves, floating lemon wedge, or cappuccino froth through the glass. For packing, I recommend wrapping the tumbler in a layer of bubble wrap just as a precaution. Though the tumbler is break-resistant, you won't want to do any vigorous stirring with a metal utensil.