The Cauldryn smart 16 oz vacuum flask can heat up water … as long as you’re not in a rush
Purchasing a product using one of our affiliate links earns us a commission and supports this site at no additional cost to you. See our disclosures here.
A flask is a travel essential, especially in winter, but the basic design hasn’t changed in years. Cue the Cauldryn Coffee smart flask, a 16 oz. vacuum flask that can keep drinks hot for 10 hours. And that’s just for starters.
At 10.5 in/266mm tall (with the battery attached) Cauldryn Coffee is reasonably large, and at 1.65 lbs/750g weight, does constitute a rather large part of a backpack.
Although it has some advanced features, keeping drinks hot for 10 hours is a laudable effort and one that will immediately make Cauldryn Coffee attractive to travelers. However, it also has several accessories.
OK, here goes. There’s a battery that provides heat, and an optional larger battery has a couple of USB outputs that can be used to recharge smartphones and tablets. Other optional accessories include an in-car 5V adaptor, a bolt-on that grinds and percolates coffee beans, an LED lantern that also kills insects, and a Bluetooth speaker module for streaming music from a phone.
A small display on the side tells you the temperature of the contents in either °F or °C, but the trouble with Cauldryn Coffee is its lack of speed. It’s great not having to mess around with gas, but as well as fretting about whether the flask’s base is charged-up before a trip, boiling water takes a long, long time. It takes about 10 minutes to heat up water for a few cups of coffee on a gas canister. On Cauldryn Coffee, it takes about 40 minutes.
We like Cauldryn Coffee’s modular design and the fact that it makes it possible for travelers to take camping gear on a plane. Not having to mess about with gas is great, but it just takes so long to heat-up water that we think, performance-wise, Cauldryn Coffee is not brilliantly practical for camping. It’s actually best suited to commuters, drivers, and hikers, all of whom can switch on the flask well before they need hot water or use the temperature regulation feature to just keep drinks warm.