Can Coffee Go In a Hydro Flask? Will It Affect Taste?

Hydro Flasks are great for keeping drinks cold and hot but what about coffee? Can coffee go in a Hydro Flask?

Will coffee damage a Hydro Flask or even worse, will the Hydro Flask change the taste of your coffee?

Hydro Flasks are made out of 18/8 stainless steel which is non-reactive to coffee and doesn't leech. It should keep your coffee hot for longer without changing the flavor, however some people claim it does change the taste so you'll need to test it for yourself.

I absolutely love my coffee. I've worked as a barista in an espresso bar, grind my own beans by hand and drink multiple coffees per day.

I'm a certified coffee snob and to me coffee is life. My partner loves coffee, heck even my kids love having a sip of my coffee. I know my coffee and I am passionate about coffee.

Generally I drink my coffee out of a glass keep cup or a paper cup from the coffee shop. But the coffee doesn't last very long and gets cold quickly.

So could I use a Hydro Flask for my coffee or will it change the taste?

I wanted to find out so I did some research and experimenting of my own.

Can Hot Coffee Go In a Hydro Flask?

People often talk about coffee's “acidity levels” so you can be forgiven in wondering whether or not the acid in your coffee might react with the stainless steel of your Hydro Flask and potentially damage your Hydro Flask or make your coffee taste funny.

Stainless steel can actually react to highly acidic substances and this can cause metal leaching into your drink.

But actually coffee is NOT very acidic. It has a PH level of 4.5-6.0 whereas the PH of soda is around 2.52 for coke and the PH of lemon juice is around 2.0.

Each number in the PH scale is 10x the previous number so soda and lemon juice are A LOT more acidic than coffee. Plus you generally mix coffee with milk which has a very neutral PH.

Hot coffee can go in a Hydro Flask without causing it damaging or changing the flavor. Coffee is not very acidic and coffee with milk even less so. The acidity levels are not high enough to react with or corrode the stainless steel.

Coffee Machines Are Made From Stainless Steel

I think it's also important to point out the fact that most coffee machines are made out of stainless steel.

For espresso, which is the most common coffee at good espresso bars, the coffee is ground and placed in the group handle which is made from stainless steel.

Hot water passes through the coffee and down the stainless steel spout into your cup.

The steaming wand is also made from stainless steel and the milk jugs used to heat the milk in…also stainless steel.

So your entire coffee is being prepped and made using stainless steel appliances.

However, this stainless steel is a slightly different grade to a Hydro Flask because it needs to be more durable. So this is the only difference.

Below you can see the grade of my milk jug which is XXXX stainless steel. The Hydro Flask is 18/8 stainless steel but the differences are minor.

If you're making a pour over coffee then chances are your jug with the gooseneck spout is stainless steel. Though glass and paper filters are used to make the coffee.

Cold brew coffee is generally made in glass and doesn't use any stainless steel.

Can You Put Iced Coffee in a Hydro Flask?

Yes, you can put iced coffee in a Hydro Flask. Coffee is not very acidic and the stainless steel shouldn't react or change the flavor. It's also less likely to react to iced coffee than hot coffee.

Just like hot coffee iced coffee has a PH level that isn't very acidic. Being iced however means it's colder and thus even less likely to react with the stainless steel and change it's flavor.

The vacuum insulation in the Hydro Flask will also help to keep the iced coffee cold for a long period of time.

Hydro Flask can keep drinks ice cold for up to 24 hours but iced coffee doesn't usually have lots of ice in it so 6-12 hours is a more reasonable expectation.

Does A Hydro Flask Make Coffee Taste Different?

A Hydro Flask is made from kitchen grade 18/8 stainless steel and so it shouldn't react with coffee or make it taste different. Most coffee is made in stainless steel machines anyway. However, some people do claim it changes the flavor of their coffee.

Hydro Flasks are made from 18/8 stainless steel which means they have 18% chromium and 8% nickel. The chromium level helps the stainless steel to be non-reactive and the nickel adds strength.

This type of stainless steel is considered to be non-reactive and is used widely in everything from cutlery to cookware to drink bottles to tumblers. In theory the stainless steel in Hydro Flask bottles shouldn't change the flavor of your coffee however some people claim it can change the flavor and I believe there is credibility in this statement.

This reddit post has a variety of answers from people, some claiming no change others claiming big changes in flavor.

Here are some of the comments from people who think stainless steel does ruin the flavor of coffee:

I honestly think coffee from any stainless tumblr tastes like a**, brand new, or washed, or whatever. I can't put my coffee in them.

I hate coffee out of stainless steel too. I can definitely taste it.

I'm the same way. Hate coffee in stainless steel. There's a brand called Bubba that makes a stainless travel mug with ceramic interior. Can buy in Amazon.

See the Bubba ceramic/stainless steel travel mug at Amazon

My Experiment

My girlfriend has long claimed she hates the taste of anything in stainless steel bottles. I personally can't taste the difference but she claims everything from water to coffee tastes different out of a stainless steel bottle.

So I made coffee, one in a ceramic cup and one in a Hydro Flask.

I then poured a little bit of each cup into identical glass cups and asked her to taste them.

OMG you should have seen the disgust on her face when she tasted the one from the Hydro Flask. She knew instantly it was from the metal container and said “All I can taste is metal! How can you drink that?!”

Yes my girlfriend is a bit dramatic but she could clearly tell the difference.

Me personally I couldn't taste the difference and I don't get it because my coffee machine and milk jugs are all made from stainless steel.

Ultimately I think it may affect the flavor, but it comes down to your pallet and whether or not you can taste it.

How Long Does Coffee Stay Hot In a Hydro Flask?

Hydro Flasks are rated to keep drinks hot for up to 12 hours, but that is when you are starting with boiling water. Coffee is rarely that hot

The temperature of coffee is generally around 139–149°F (55–65°C). This will stay hot enough to drink for 3-6 hours in your Hydro Flask, maybe even a little longer. By 12 hours your coffee will be lukewarm at best.

Can You Put Coffee In a Hydro Flask Cup/Mug?

Hydro Flask also make tumbler cups, wine and spirit tumblers and mugs. These are made from the same material at the Hydro Flask bottles and thus are fine to drink from.

Hydro Flask cups and mugs are made from 18/8 stainless steel which is safe to drink coffee from. It shouldn't affect the flavor of the coffee but some people claim it does.

Hydro Flask mugs and cups are also double walled and vacuum insulated so they should keep coffee hot for hours at a time.

What Is The Best Hydro Flask For Coffee?

There are a wide variety of Hydro Flask bottles out there and some of them are better for coffee than others. I've written an entire article on the best Hydro Flasks for coffee but below are some of the best Hydro Flask bottles for coffee:

Best Hydro Flask Bottle For Coffee: 12oz or 16oz Coffee Bottle

The coffee flasks come in 3 sizes (12oz, 16oz and 20oz) with the Flex Sip Lid which is designed to be completely leak proof when closed by can be easily twisted open giving you a little coffee spout to drink from.

I personally prefer the 12 oz size as where I live a 12oz is a large coffee with 2 shots of coffee and milk. It's rare to find a place here that does 16oz or 20oz coffees.

See the latest price of the 12oz Coffee Hydro Flask at Amazon

However, I know there are a lot of people out there who make their coffee at home or who go to shops where you can buy much larger cups of coffee.

For that Hydro Flask have the larger 16 oz and and 20 oz sizes which are basically the exact same as the 12 oz only taller.

Same diameter, same color options, same insulation, same lid – only taller and can hold more liquid.

See the latest price of the 16 oz Coffee Hydro Flask at Amazon

See the latest price of the 20 oz Coffee Hydro Flask at Amazon

Best Hydro Flask Mug For Coffee: 12 oz Coffee Mug

If you're specifically after a mug with a handle rather than a tall bottle style flask then Hydro Flask do make a 12 oz Coffee Mug which, as you guessed, is designed for your coffee.

The mug is much shorter and wider than the flasks mentioned above. This makes them better for latte art and better for use at home or in the office giving you that more snug coffee vibe.

But it's vacuum insulated to keep your coffee hot for hours and it comes in a variety of cool colors.

See the latest price of the Hydro Flask 12 oz Mug at Amazon

Can You Take a Hydro Flask To Starbucks or Other Coffee Shops?

Most coffee shops allow keep cups (when there isn't a corona virus) and thus they will happily take your Hydro Flask and fill it up with coffee.

When your Hydro Flask is extremely large and tall there is a chance that it may not fit under their machine. In this case the barista will likely do your coffee shots into a ceramic cup and then pour the coffee shot into your Hydro Flask.

This isn't ideal for taste but if you're drinking a large coffee with lots of milk and sugar you likely won't notice the difference anyway.

What Is The Best Hydro Flask Lid For Coffee?

If you already have a Hydro Flask then you may want to get a different lid for it that is specifically suited to coffee. So what is the best Hydro Flask lid for coffee?

The best Hydro Flask lid for coffee is no lid. This allows you to smell the aroma of the coffee which improves flavor. But if you need a lid then the wide mouth flex sip cap is the best option as it's leak proof with a sipping spout designed for coffee.

See the latest price of the Hydro Flask Flex Sip Cap at Amazon