How to make my thermos flask not ruin my coffee?

July 6, 2009 4:35 PM

How to make my thermos flask not ruin my coffee?

I bought a thermos flask, and it is making my coffee taste like dreck - horrible plastic-y dreck. That said, I've only given it two tries so far, and the foul taste seems to be weakening. Is there something I can do/soak with/heat/cool/manipulate to get more quickly to the point where I actually enjoy drinking the coffee?

posted by pompomtom to food & drink (12 comments total)

No. All plastic thermoses do this.

You need a glass (lined) thermos with a stainless steel threaded cap.

If your coffee sits touching plastic for hours, it will always suck.
posted by rokusan at 4:40 PM on July 6

If you are prone to breaking things (like me), there are also stainless steel themoses without glass. I find that my stainless steel thermos still changes the flavour of my coffee somewhat, but maybe that's because I put milk in and drinking it 2-3 hours later. (You can't leave it for 6-8 hours with milk - the milk will go sour). But it's still quite drinkable, and without milk I've never noticed a difference (milk can be carried separately).
posted by jb at 4:57 PM on July 6

You're probably getting a mouthful of Bisphenol A. Tasty, huh?

I've had this Nissan Thermos for ages. I don't know what alien material it's made of, but it never changes the flavour of my coffee and liquids are still hot(-ish) 24-hours later.
posted by foooooogasm at 5:28 PM on July 6

"You're probably getting a mouthful of Bisphenol A. Tasty, huh?"

Bisphenol A does not have a taste. (about halfway down the page) But thanks for the alarmist answer.

To echo the other opinions, switch to stainless steel. I use this bullet bottle and don't have any issues with the coffee tasting bad.
posted by cabingirl at 5:41 PM on July 6 [1 favorite]

The "plastic-y taste" is not a reliable sign of bisphenol A leaching. The chemical doesn't appear to have a taste.

That certainly sounds definitive to me, coming from someone who isn't a chemist responding to questions published in an online newspaper. Check you sources, much?

Even if a chemical doesn't have a taste or an odor doesn't mean it's non-reactive. Try tasting pompomtom's coffee and see if that's the case. Better yet, maybe audit an organic chemistry course this summer before calling someone alarmist.
posted by foooooogasm at 5:55 PM on July 6

PPT, I use a Sigg Trend thermos. It's all stainless and doesn't ruin the coffee too much. I got Paddy Pallin on Lt Bourke Street to order me one in.
posted by tim_in_oz at 5:55 PM on July 6

I never said that there wasn't bisphenol A in the plastic thermos - how could I know that? All I said was that it doesn't have a taste. That "plastic" taste is exactly what manufacturers were trying to avoid by adding bisphenol A to polycarbonate.

Regarding your misinformed comments about reactivity, bisphenol A is non-reactive per NFPA criteria. You know, the diamond logo on the wikipedia article you linked to? Not that that matters, since reactivity has nothing to do with it leaching into water.

And now, I will wait for these comments to be flagged.
posted by cabingirl at 7:09 PM on July 6 [1 favorite]

This is a serious question, and I don't think there is really a proper travel mug out there that doesn't alter the taste. The Thermos one is a bad offender, but it becomes tolerable. I had to stop drinking from my stainless steel one because it imparted a slightly metallic taste. Often, if it's not the mug, it's the plastic lid that alters the coffee taste.

You can try thoroughly rinsing your mug (and its lid) in a part vinegar / warm-hot water solution. Make sure you rinse out all of the vinegar with soapy water.

Right now I commute with a porcelain mug with a silicone lid, and it's about the best solution I could find to the bad-tasting-travel-mug problem.
posted by jabberjaw at 8:40 PM on July 6

Per the other commenters: simple. Plastic = gross taste. Steel = pretty okay, still cheap. Glass = best; can be pricey. I am a big snob and I use a steel thermos.
posted by mindsound at 8:40 PM on July 6

the "contigo extreme mug" is vacuum insulated glass and is the only travel mug i've ever been able to stand for more than a few days. it is totally great in every way! sorry i had problems making a link, just google "contigo mug"
posted by cvilleluke at 9:16 PM on July 6

You could try making a paste of bicarb soda, applying that for an hour or two, rinsing and let it dry and air. That seemed to help with a similar problem I had with the water reservoir of my coffee maker. Perhaps you should make a super-strong coffee solution (hot) and leave that in the flask overnight - the idea being that the heat will continue the leeching effect but the strong coffee might start to mask the taste. If it's better after two tries, perhaps the overnight sacrifice coffee might work well.

But really it's just going to take time. You could bite the bullet and get nice glass-lined thermos. With care, those things last forever. Aladdin (I think) do a ruggedized version which will stand up to a fair amount of abuse, if you're worrying about the glass liner.
posted by ninazer0 at 9:41 PM on July 6

Bah, not Aladdin. It's Stanley that I'm thinking of.
posted by ninazer0 at 9:44 PM on July 6