Why Does My Hydro Flask Smell Like Metal? Remove Metallic Taste

Sometimes a new Hydro Flask or even an older Hydro Flask can start to smell strongly of metal and can impart a metallic taste and metallic smell into your water or other drinks.

I have noticed this in the past with my Hydro Flask so I wanted to work out why does my Hydro Flask smell like metal and how can I fix it?

Here's what I found:

Your Hydro Flask may smell or taste like metal due to bacteria build up or metal leeching and issues with the stainless steel. Soaking your Hydro Flask in a vinegar/water mix often fixes the problem.

However, some people (like my girlfriend) are extremely sensitive to the metallic taste of Hydro Flask or other metal bottles. My girlfriend hates drinking out of stainless steel and claims she can taste the difference even when I can't notice anything.

Why Does My Hydro Flask Smell or Taste Like Metal?

There are actually a few different reasons your Hydro Flask may smell or taste metal.

This is a fairly common concern among some people. Check out this extreme example from this Reddit post:

Why does my expensive and “safe” 18/8 food grade stainless bottle smell like it is trying to poison me (strong metallic smell) if I leave water in it for a while.

(Noticeable smell after 4 hours or so, terrible after 24)

Some of these can be fixed with a simple clean while others might require you to get a new bottle.

Bacteria Build Up

Even if you're only drinking water out of your Hydro Flask bacteria and mold can build up over time.

Sometimes these bacteria can release acids which can corrode the stainless steel in small amounts and can the metal to smell more strongly or to leech into your drinks.


If you have used bleach in your Hydro Flask or you have just noticed that your Hydro Flask is starting to rust a little bit in areas then this could also be causing the smell and flavor of metal more than usual.

If you have rust in your Hydro Flask that needs to be removed then click here to learn how to remove rust from your Hydro Flask.

Acidic Drinks

Acidic drinks like coffee, tea, soda and especially lemon juice and lemon water can actually start to corrode the stainless steel a tiny bit and lead to more metal leeching.

This might not be very noticeable in your acidic drink but when you go to put water in your Hydro Flask it may leave your water tasting metallic.

Metal Leeching

In my article of if Hydro Flasks cause cancer I looked in detail at metal leeching and if it is likely to happen.

This study states:

“Stainless (steel) is readily attacked by organic acids, particularly at cooking temperatures; hence iron, chromium and nickel should be released from the material into the food”

According to wikipedia Chromium oxide (which forms the protective layer over stainless steel and stops it rusting) can sometimes leech into drinks.

Although insoluble in water, it reacts with acid to produce salts of hydrated chromium ions….It is also attacked by concentrated alkali to yield salts.

So it's likely that some metal leeching happens regardless of if you're just using your Hydro Flask for water or if you're using it for acidic drinks.

Your Hydro Flask Is Fake

I have seen YouTube videos where people talked about their fake Hydro Flasks giving off a strong smell of metal or chemicals.

I would assume this could also affect the flavor. Click here to learn if your Hydro Flask is fake.

Sensitivity To Metal Taste

Some people are just extremely sensitive to the metallic taste of stainless steel water bottles. My girlfriend is one of these people.

Even when I pour water out of a Hydro Flask and into a glass cup she can still taste the difference while I can't tell at all.

If you're extremely sensitive to the taste and smell of Hydro Flasks and other stainless steel water bottles you might want to consider a ceramic lined insulated bottle or a glass lined thermos as these have a layer of ceramic or glass that stop the stainless steel from imparting any flavors into your drink.

How To Remove Metallic Smell and Taste From Your Hydro Flask

If you find your Hydro Flask has a stronger than usual metallic smell or is imparting stronger than usually metallic tastes into your water or other drinks then here is how to get rid of it.

Step 1: Wash Your Bottle Well

First give your Hydro Flask a good wash in warm soapy water.

Use a bottle brush and give it a good scrub on the inside, taking your time to clean it really well.

Step 2: Fill Your Bottle Up With Vinegar and Water

Once cleaned out you'll want to fill up your bottle with a mixture of vinegar and water at a 1:1 ratio. This means 50% vinegar and 50% water.

So if you have an 20 oz Hydro Flask you'll want to put in 10 oz of vinegar and 10 oz of water.

Step 3: Leave To Soak For 24 Hours

Once completely filled with vinegar leave your Hydro Flask to soak overnight or ideally for 24 hours.

The vinegar will help to kill bacteria and viruses, will break down grease and mold buildup and help to neutralize the metallic smell of your bottle.

Step 4: Pour Out and Rinse Well

Pour out your vinegar and water mixture and give your Hydro Flask a good rinse under running water. Make sure to get all the vinegar out.

Step 5: Leave Bottle Open To Air Dry

Lastly you'll want to leave your Hydro Flask to air dry.

When the stainless steel is exposed to the air the chromium in the metal reacts with the oxygen in the air to create a protective layer over the metal.

So leaving it to air dry somewhere can help this process and help your Hydro Flask to stop smelling so strongly.

Also Try: Sacrificial Boiling Water

Another thing you can try to remove the metallic taste from your Hydro Flask is to boil some water and fill your Hydro Flask up with boiling water.

Leave it to soak for a few hours or overnight. Put the lid on if you want to keep the water hot.

Then pour the water down the drain. The boiling water can help to draw out some of the bad smells and taste.

You can repeat this process multiple times, hopefully dulling or removing the metal smell or taste in the process.

If You Can't Remove The Metallic Taste

If you've tried the above without success and you're still finding an extreme metallic smell or extreme metallic taste in your Hydro Flask then there are a few different things you can do.

Contact Hydro Flask For a Replacement

It is possible for the stainless steel in a Hydro Flask to have a defect where there aren't the right amounts of chromium and nickel, or they aren't distributed properly through the Hydro Flask.

This could lead to a metallic smell and taste and this MAY be covered under warranty.

You'll need to get in contact with Hydro Flask though and see what they have to say. Click here to go to Hydro Flask's warranty page.

Get a Ceramic Lined Insulated Bottle

Maybe your sensitive to the metallic taste of the Hydro Flask or maybe you can't fix your bottle and get it replaced so you need to buy something else.

If you want a vacuum insulated bottle that can keep drinks hot or cold for hours then you may want to consider a ceramic lined insulated bottle.

These are still made from stainless steel but they have a ceramic liner over the top so your drink never actually comes into contact with metal.

This can stop the metallic taste and smell of your drinks and is something that I know coffee and tea lovers will appreciate. Click here to see my list of the best ceramic lined insulated tumblers.

Best Ceramic Lined Travel Mugs

Get a Glass Lined Thermos

You can also consider a glass lined thermos instead of a ceramic one.

These tend to break easier and be not as durable, but if you prefer glass then they may be the best option for you.

See my list of the best glass lined thermoses

Best Glass Lined Thermos

Try a Double Wall Glass Water Bottle Instead

Maybe you want to get away from stainless steel altogether and have a water bottle that is completely glass instead.

There are some good double walled glass bottles. These aren't vacuum insulated so they won't keep drinks as cold or hot for as long as a Hydro Flask, but they still work better than single wall cups and can be a good alternative.