I need to drink 1 litre of black tea a day, and as such I purchased a Quechua 1-litre, 18/8 stainless steel hiking water bottle from Decathlon, in order to make the tea in the morning and then be able to put it in there so that I can drink it during the morning/early afternoon hours.

My two concerns about this are:

1. Can I put the hot water/tea in the bottle right after boiling/making it safely (i.e., without risking to eventually cause the bottle to leach/rust from the inside into my drink)?

2. As black tea is fairly acidic, is it still safe to have it in the bottle over the course of a few hours every day (especially at high-ish temperatures), or is it likely to, again, eventually cause the steel to rust and/or leach its compounds into the drink(s) inside?

As a reference, in the product description of the bottle (https://www.decathlon.co.uk/p/stainless-steel-hiking-flask-with-screw-cap-mh100-1-l/_/R-p-330040?mc=8612480), it is mentioned that the bottle is: *”non-isothermal”*, that it is *”suitable for fizzy drinks”*, and that it *”can be used for hot drinks but they get cold quickly and the flask will get very hot if not boiling.”* Also, not sure if it’s relevant but the cap is 90% stainless steel and 10% silicone (while the body is 100% stainless steel).

Any input is greatly appreciated.

EDIT: Below are three Reddit comments that advise against storing hot water and/or tea in stainless steel containers (in case you want to have a counter argument to challenge):

1. https://www.reddit.com/r/Survival/comments/1se56p/comment/cdyrrbh/?utm_medium=android_app&utm_source=share&context=3

2. https://www.reddit.com/r/CampingandHiking/comments/9o3e4j/comment/e7t1cig/?utm_medium=android_app&utm_source=share&context=3

3. https://www.reddit.com/r/explainlikeimfive/comments/8uozkp/comment/e1h4pib/?utm_medium=android_app&utm_source=share&context=3

5 comments

  1. Black tea keeps quite well in a bottle if the bottle is full. It oxidises quite quickly if exposed to air, so once you start drinking it, don’t leave it too long (hours) in a half full bottle.

    I’m not familiar with the Quechua bottle you mention, but using a stainless steel Thermos ([an actual Thermos unit](https://www.amazon.co.uk/gp/product/B074RBJXWN/)) I can keep tea warm for quite a few hours. Being stainless steel, the tea does not attack the interior surface. You will get some tannin deposits over time, but they can be cleaned out by placing a dishwashing tablet in the thermos and filling it with hot water. Leave it for a while (30-60 minutes) and then use a large bottle brush to scrub out the interior. Repeat if it’s still not clean.

    You can also carry cold tea, if you wish. Make tea as usual, then place it in a pan and put the pan in a sink of cold water to cool it quickly. You can simply make the tea in the pan if you want. Having cooled the tea to near room temperature, transfer it to the fridge to finish cooling it.

  2. I wouldn’t expect any issues apart from that that they mention (flask will be hot and burning to carry initially and then your tea will go cold as it’s not a thermas). Heat won’t cause it to rust alone though it can speed up the process but over the timeframe I wouldn’t worry and there’s nothing wrong inheritantly with rust anyway from a health point of view it’s just iron

  3. Why do you need to drink 1 litre of black tea per day?

    What would happen if you weren’t able to?

  4. It’s impossible to know the quality of the steel that was used to make the bottle and if there is a coating, what it is made of. If your kettle is plastic that may possibly be worse.

  5. It’s unlikely to rust enough in your lifetime to be an issue.

    I used to work in a cafe where we made tea in stainless tea pots. So they’d have boiling tea in them for nearly the entire day, every day, for years. Didn’t see any with rust.

    Like someone else says, rust is only iron which is something your body needs anyway. If you were chewing flakes of it, probably not great but a few crumbs in water is very probably not an issue.

    Do you like your tea cold? Seems like an uninsulated bottle is the worst idea, because most people like it hot. If you’re really worried then a glass bottle would be just as good and you can get one given away free full of some other drink.

    If you like hot tea then a glass or stainless vacuum flask (Stanley thermos for preference) will be much better.

    Obviously your tea bottle will be too hot to carry if you fill it with boiling tea, so be careful!

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