How to maintain coffee flavor all day in vacuum thermos

by Graham
(Holly Springs, NC)


I work long shifts at a mall kiosk with no access to a coffee maker. I need to be able to make coffee in the morning and have it hot and tasty all day.

Like a good coffee snob, I have been fresh grinding the beans and making coffee in a thoroughly-cleaned french press in the morning and pouring it into a thoroughly-cleaned vacuum sealed thermos so I can have hot tasty cups of coffee all day at work.

Unfortunately, while the coffee tastes great in the morning, as the day goes on it seems to become more acidic such that the sourness eventually overpowers everything else. What I suspect is happening is the constant heat in the thermos is ruining the coffee's flavor over the course of the day.

I need some suggestions for making coffee that will keep well in a thermos. I usually prefer coffee black and strong, but I've tried adding some milk and sugar to the mix in order to mitigate the flavor degradation- however this was to no avail.

This might be a terrible idea but I've thought about putting some coffee in a tea ball and putting that in the thermos so that as the acidity grows throughout the day at least there will be some counter-acting bitterness.

Thanks for your help!


Tough question. : )

While the thermos is keeping your coffee hot, at the same time it is also allowing the hot coffee to slowly stew.

A thermos is great for keeping coffee hot for an hour or two, without too much loss in the quality of the coffee. But for a full day, that’s asking too much

And I think your tea ball idea will simply add to the nasty taste.

But here is something you can do.

Don’t fill your thermos with coffee, fill it with hot water.

Then get yourself a coffee press mug from Amazon.

When you want fresh coffee, put ground coffee in the travel mug, add hot water from the thermos, wait a bit, push down the plunger, and presto – fresh coffee!

Hope this helps.

Comments for How to maintain coffee flavor all day in vacuum thermos

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Jan 08, 2011
Cold Brew May be the worth a try
by: Electric Beanz Coffee Bar

Another idea is to make a cold brew concentrate to leave and keep at work for up to 14 days. As suggested, carry only hot water in your thermos and use it to mix with your cold brew concentrate. Surprisingly, this will make a delicious, bitter-free cup of coffee, assuming you start with a good quality coffee. Most cold brew methods call for a 4:1 ratio of water to coffee concentrate.

Sep 05, 2010
chill out ! ,,, LoL
by: pistachio


In the morning and for as long as it lasts with a
" right " flavor,, have your coffee.....

here is my suggestion.....

make a batch of Iced Coffee and if iced right after brewing there is no burning or taste degradation...

mix it to your taste in a second thermos,,, and I am sure past 11 am your going to be fine with it!

to wit,,, if you use milk in your coffee,, skip using 1/2 & 1/2 [which is really a 70% - 30% blend] and,,,,,

go ALL THE WAY to heavy whipping cream,,,,,

I know you will be happy!


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