Coffee goes in at home, I want it drinkable four hours later at the desk. The flask lives in a rucksack with a laptop and gets dropped onto tiled floors maybe once a month. My last one was plastic bodied and cracked at the thread after eight months. Under 40 there seem to be both stainless double wall and glass lined options, and the glass ones claim better taste. Which one survives this treatment?
The durability question at this price is not the vacuum, it is whether you can clean it. A flask that cannot be taken apart grows a coffee oil film inside the lid, then everything tastes of yesterday, then you stop using it. Any flask with a bayonet lid and a sealed drinking spout is on a two year clock in practice.
Soaking the lid in a cup of hot water with a spoon of bicarb once a fortnight does a lot for the ones that do not come apart. Not a fix, but it buys you time.
Mild disagreement with the thread above: glass really does taste better, and if this were a flask that lived on a desk I would say buy glass. It is the drops that decide it. In a rucksack with a laptop, buy stainless and accept that black coffee will taste very slightly metallic for the first month until it seasons.
Whatever you buy, do not put it in the dishwasher. Dishwasher heat is what kills the seal on most of these, and the manuals all say hand wash for that reason.
@wanderport · 2mo ago · 3 replies
Stainless, and it is not close given the rucksack and the tiled floor. A glass liner is a vacuum flask inside a shell, and a single hard drop cracks the liner even when the outside looks perfect. You find out because it stops holding heat.
Four hours of hot is easy for any double wall stainless, so ignore the marketing numbers. The things that decide whether it lasts are the lid and the gasket. Look for a lid you can fully disassemble, a replaceable silicone gasket, and a stainless thread rather than a plastic collar, because the plastic collar is exactly what cracked on your old one. Wide mouth cleans better, narrow mouth holds heat better; at four hours take the wide mouth.
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@leafspot_lia · 2mo ago
Second the replaceable gasket. Mine is six years old and on its third gasket, which cost about four dollars total.
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@seasonalpalette · 2mo ago
Had not thought about whether the lid comes apart. Half the reason I replaced the last one was that it started smelling and I could not get inside the lid to clean it.
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