Are you able to put lemon juice or lemon water in your Hydro Flask or will it cause damage to your Hydro Flask or make it taste bad?
Hydro Flasks are great to keep water icy cold all day. They encourage you to drink more water and make water more enjoyable to drink (no more lukewarm or hot water after leaving it in the car).
But what if you want to add a bit of lemon juice to your water to make it taste nicer and also gain the health benefits from the lemon.
Can you do this or will it cause damage to your Hydro Flask?
A lot of people believe it's fine to put lemons in a Hydro Flask as research states that lemon juice, while acidic, should NOT affect the stainless steel metal that Hydro Flasks are made from. However, some people claim it creates a metallic taste and others that it can leech metal into your drinks.
Ultimately there is no definitive answer on this one however I have done a lot of research into this which I want to share with you.
Why Are People Concerned About Lemons In Their Hydro Flask?
Lemons contain a high amount of citric acid and therefore are quite acidic. Lemon juice has a pH between 2-3 which makes it 100,000 times more acidic than water (according to healthline).
This makes lemon juice highly corrosive and extensive contact with metal can cause micro particle leaching which could ultimately cause you to consume micro-metal particle corrosion.
This could potential pose health risks or could cause your drinks to taste metallic.
Is Lemon Water Safe In Your Hydro Flask?
My best friend loves a bit of lemon water. When ever she is sick she chugs the stuff and she absolutely loves lemon tea.
I wanted to find out for her if lemon water is safe in he Hydro Flask (or any other stainless steel water bottle).
What People Are Saying about Lemon Water in Hydro Flasks
This question was asked here on Amazon with some people saying you could completely fill it with pure lemon water and it will be fine while others saying “definitely don't do this” as it can create a metallic taste in the water.
There was also a bunch of posts on Reddit (here, here and here) asking the question with mixed responses. Most people saying it's fine and they have no issues with it with some minor complaints about a sour smell.
The question was also asked in this forum post asking if lemon juice would damage the stainless steel in a Hydro Flask. The general consensus in this post was that the stainless steel used in Hydro Flask is resistant to corrosion from both acids and bases and it's easy to keep clean.
What Does Hydro Flask Say?
Hydro Flask don't answer this question anywhere on their website, nor is it in any of their marketing material.
However, I did find this facebook post from June 2016 where someone asked “Is lemon water safe for my Hydro Flask? I got my first on last week and I LOVE it!”
The official Hydro Flask account then responded with
Yes, totally safe.Hydro Flask
What Do The Scientists and Metal Workers Say About Lemon in Hydro Flasks/Stainless Steel
Most of the responses so far have been people's opinion and a Hydro Flask response on Facebook doesn't necessarily mean the company has tested this and verified it. It could just be some marketing intern writing a response.
I found this great post on Finishing.com which is a website dedicated to people who are interested in metal finishing.
Someone was asking about the effects of lemon juice in guacamole on stainless steel and if it affects the flavor and adds a metallic taste to items.
This was actually a really interesting read with multiple people injecting their opinions. The biggest takeaways from the article were:
18/8 Stainless Steel is Corrosive Resistant
Most of the people in this thread talk about the different types of stainless steel with 18/8 also known as “grade 304” are corrossion resistant and safe for use with pretty much everything.
This quote from Ray Kremer sums it up nicely:
I can't quote chapter and verse to you, but the FDA has long approved of 304/316 stainless steel as a safe material for contact with pretty much everything. If you can track down a citation I would hope that would trump your state department of agriculture.
Klean Kanteen Founder Wasn't Confident In Lemon Water
There is a comment in this thread that is apparently from Robert Seals (not verified) who started Klean Kanteen. He says:
A. I am Robert Seals the inventor of Klean Kanteen which started the stainless vs plastic revolution; I sold the company years ago. I had the bottles tested back then because as a metal worker I was concerned about electropolishing, which I did not trust. Using an acid equivalent to lemon juice it was found to leach nickel over the acceptable amount allowed by FDA standards. I was concerned enough to print FOR WATER ONLY on the bottles as the same tests showed no detectable metal when water was used.
Electro polishing is not the way to passivate any food container. The old fashioned polishing method is by far is the best way to seal the metal but it's too labor intensive for production. The public is being duped on this one. Robert Seals
This is a really interested revelation. Klean Kanteen launched in 2002 (a full 7 years before Hydro Flask) and it's unsure if they used a citric acid for this test or some other type of acid. But still it's an interesting piece of commentary.
So from that I got the idea that having lemon water in Hydro Flask SHOULD be ok but there is the potential that it MAY leech some metals into your drink. However, this hasn't really been solidly tested.
Will Putting Lemon In Hydro Flask Make It Taste or Smell Bad?
As I was doing my research for this I saw quite a few people saying that after they used lemon water in their Hydro Flask they noticed a more metallic taste in their drinks.
The Facebook post mentioned above has someone saying:
After I put lemon water in my hydro flax it now has a metallic taste. Can I do anything about that?
From the customer reports as well as the details from the metal workers as well as the founder of Klean Kanteen it appears that there is some potential for lemon juice to leech some metals into your drink. This would explain the metallic taste.
As to the safety of this I did do a full article on whether or not Hydro Flasks cause cancer and we talk about that in much more detail there.
The short of it is that drinking small amounts of the nickel, chromium or iron in stainless steel is unlikely to cause any major health problems but there are no specific studies dedicated to this.
Plastic Is Likely Worse
The acidic nature of lemon juice can cause plastics to leech chemicals into your drink. From the bits and pieces I've read plastics are worse in this department than the stainless steel used in Hydro Flasks.
Some people say it doesn't, but most people seem to think the acidity level of lemon juice will leech plastics from plastic bottles:
This quote from a Quora answer sums it up:
the acid in lemon cause plasticizing agents to leach out of plastic
So when it comes to “which is the lesser evil” then stainless steel seems better than plastics. Though I would personally need to do more research into this matter to be confident in that 100% and to be honest with you I haven't done that yet.
Will Lemon or Lemon Water Affect Your Hydro Flask Lids?
Given that lemon juice is so acidity then I would personally be concerned that while the stainless steel may be fine with your lemon water the plastic lid of your Hydro Flask may not.
Hydro Flask lids don't contain BPA, which is known to be a harmful substance, but I'm still not completely confident that lemon juice wouldn't leech other harmful chemicals into my drink.
Get a Stainless Steel Lid If You're Using Lemon Water In Your Hydro Flask
If you're putting lemon water or lemon juice in your Hydro Flask on a regular basis then you may want to avoid the use of plastic lids altogether and instead use a stainless steel lid (you can pick up this stainless steel lid for an affordable price at Amazon).
They are made by a third party company but they are designed to fit on the wide mouth Hydro Flask bottles.
How To Clean The Lemon Taste Out Of Your Hydro Flask
If you are finding that after having lemon juice or lemon water in your Hydro Flask you can't get out the taste of lemon or the taste of metal then there are some things you can do to help remove this taste:
Fill up your Hydro Flask with a bit of vinegar and swirl it around of give it a shake with the lid closed. Then leave it to sit for 15-30 minutes before rinsing out.
The vinegar should clear away the lemon smell/taste.
But it's important to note that vinegar has a similar acidity to lemon juice so if it's corrosion that has you concerned then this may not be the best choice.
Fill up your Hydro Flask with boiling water and leave to sit for a few hours. This will help to soak up any residual lemon smell/flavor.
Then tip out the water and repeat the process until the smell or taste is gone.
Because water isn't acidic it shouldn't corrode the stainless steel at all.
Dry Rice Clean
Sometimes drinks can leave residue on the inside of your bottles that is hard to wash away and that a standard clean doesn't get rid of.
You can't really see this on the inside of a Hydro Flask as the bottle is not see through. I talk more about this process in my article on getting rid of smells and mold in your Hydro Flask but the process is really quite simple.
- Put some dry white rice in your Hydro Flask
- Put in some water (and vinegar or detergent if you want)
- Close lid and shake vigorously for 2-5 minutes
- Rinse out
The hard rice acts as an abrasive cleaner and cleans away a bunch of different residues which can help to remove any weird smells of flavors coming from your Hydro Flask.
Can You Put Fruit In a Hydro Flask?
Infusing fruits into your water can be a good way to consume more fruit and get the important vitamins and nutrients from the fruit.
The issue with using lemons or lemon juice in your Hydro Flask is the acidity level.
The majority of other fruits have a lower acidity level than Lemon so should be even less likely to cause corrosion than lemons would.
The only exception to this is limes which are considered to be slightly more acidic than lemons.
Other fruits that are also high in acidity (according to the master list) are cranberries, chilli sauce, grapes, plums and vinegar. Those these are generally around a PH level of 2.8 whereas lemons are 2.0-2.6.
If you wish to add fruit into your Hydro Flask then these mini fruit infusers can be a great way to do that
What To Do If You're Super Worried About Metal Leeching Into Your Water
If you're super stressed about metal compounds leeching into your water then getting a water filter lid is an extra step you can take to avoid drinking metal compounds in your water.
I wrote a full list of the best Hydro Flask lids and below are 2 filter lids that you can check out:
Aquamira Water Filter Lid
The Aquamira has a flip cap style with a rubber seal that makes it completely leak proof when closed.
The filter attaches to the top of the lid and you can use a standard filter or they have a stronger filter for out in the field that will protect you from bacteria and other harmful biological contaminants.
The Answer Water Filter System
This one comes with a straw rather than attaching to the top of the lid like the Aquamira.
It comes with a filter, the straw as well as two different lids. An Easy-Flip Sports Lid as well as the Locking Dust Cover Lid that has extra protection to keep it clean from dust particles and getting dirty.
Should You Put Lemon Water In Your Hydro Flask?
Ultimately after all the research I've done I have to say that the jury is still out on this one. There just isn't enough testing or scientific evidence to support either idea completely.
There is some evidence to support lemon juice or similar acidic substances leeching metals into your drink while there is other evidence to state that it doesn't and that the 18/8 stainless steel that Hydro Flasks are made from don't do this.
There is greater potential for the lemon juice to corrode the plastic that the lids are made out of so I would recommend this stainless steel lid if you are going to consistently put lemons in your Hydro Flask bottles.
Ultimately I'll leave it up to you to decide what you'll do and whether or not you'll use lemon juice or lemon water in your Hydro Flask.