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Liquids To Avoid Putting In A Hydro Flask Water Bottle?

When choosing liquids to carry around in your trusty Hydro Flask water bottle, not all beverages make good choices. While the versatile Hydro Flask works well for water and some other drinks, its stainless steel construction can react poorly with certain liquids over time.

Putting the wrong liquids in your Hydro Flask can lead to corrosion, staining, buildup of residue, or even voided warranties if damage occurs. So it’s important to understand which beverages to avoid storing long-term inside your Hydro Flask. This article explores the most problematic liquids and explains why they don’t belong in your durable water bottle.

Key Takeaways

  • Carbonation, acidity, sugar content, and salt can compromise Hydro Flask’s stainless steel and insulation when stored long-term
  • Avoid prolonged storage of carbonated drinks, fruit juices, sugary sodas, alcoholic beverages, and saltwater
  • Dairy, coffee, and tea are generally safe but can curdle or stain over time
  • Always handwash gently after storing problematic liquids to minimize interior damage
  • Improper liquid storage can void the Hydro Flask warranty in some cases

Why Should Certain Liquids Be Avoided in Hydro Flask Bottles?

Hydro Flask water bottles are made from pro-grade 18/8 stainless steel, an alloy containing 18% chromium and 8% nickel. This imparts strength, durability, and resistance to temperature extremes. However, some liquids can still react negatively with stainless steel over time.

Factors like acidity, carbonation, salt content, sugar concentration, and alcohol percentage can accelerate corrosion or staining. Perishable dairy products can also spoil inside a Hydro Flask bottle. Chlorinated water from pools or hot tubs can cause pitting.

So while the Hydro Flask excels at insulating hot or cold water for hours, its stainless steel interior is best suited to plain, non-reactive beverages. Take care with storing other liquids inside it long-term.

Liquids Not Ideal for Long-Term Hydro Flask Storage

LiquidAttribute Making It Not IdealPotential Damage to a Hydro Flask
Dairy ProductsPerishable and prone to bacterial growthCan lead to odors, stains, and health hazards
Carbonated BeveragesCan build up pressure inside the bottlePressure may cause leaks or affect the seal
Acidic Beverages (e.g., Lemon Juice)High acidity levelsCan corrode stainless steel
Very Sugary DrinksCan leave sticky residuesResidues are hard to clean and can attract bacteria
Alcoholic BeveragesCan corrode the stainless steelCorrosion damages the bottle and may void warranty
SaltwaterCorrosive nature due to salt contentCan corrode metal parts
Hot Beverages (above recommended temperature)Excessive heatMay damage the seal and affect thermal insulation

Now let’s explore some of the most problematic drink categories in more detail.

Can Carbonated Beverages Damage Hydro Flask Water Bottles?

Yes, the carbonation and acidity commonly found in sodas can damage Hydro Flask water bottles over time. The carbonic acid formed when CO2 dissolves in water is corrosive to stainless steel.

And many popular sodas, like colas, have a pH between 2.5 and 3.5, making them highly acidic drinks. Other carbonated beverages, such as sparkling water and beer, are less acidic but still not ideal for long-term storage.

How acidic is Coke?

Its pH is reported to be 2.6 to 2.7, mainly due to H3PO4, phosphoric acid. As a fizzy drink, it contains plenty of dissolved carbon dioxide, but this makes very little contribution to the acidity.

When carbonated drinks react with stainless steel, corrosion accelerates. This can lead to pitting, cracking, deposits building up, and bad odors inside the bottle.

While an occasional carbonated beverage in your Hydro Flask likely won’t cause issues, take care to avoid storing them inside it long-term. The reaction worsens over time, so prolonged contact multiplies the damage.

If you do store soda or beer for a short time in your bottle, clean thoroughly afterward with a bottle brush, mild detergent, and baking soda solution to halt corrosion. But for daily use, avoid carbonation to preserve your Hydro Flask.

Is It Safe to Store Dairy Products in Hydro Flask Bottles?

No, Hydro Flask water bottles are not intended for storing dairy products long-term. Milk, yogurt drinks, protein shakes, and similar perishable items can spoil inside the bottle’s sealed, insulating interior.

Even if kept refrigerated, dairy products left too long inside a Hydro Flask can still grow harmful bacteria. The warm center of thick dairy liquids takes longer to cool. And without light exposure, it’s harder to notice visual signs of spoilage.

So while your Hydro Flask bottle excels at keeping beverages cold for hours, dairy items require careful temperature regulation to stay fresh. Leaving them unattended risks foodborne illnesses.

For occasional, same-day usage, dairy beverages in your Hydro Flask are less concerning. But take care to wash thoroughly after each use to halt bacteria growth. Check for odors and discard at signs of spoilage. Never store open dairy products inside for prolonged periods.

How Do Acidic Beverages Affect Hydro Flask’s Stainless Steel?

As discussed regarding carbonated sodas, acidic liquids can damage Hydro Flask’s stainless steel over time through corrosion. This causes pitting, cracking, deposits, and staining inside the bottle.

Acidity is measured using the pH scale, with lower numbers being more acidic. Battery acid has a pH of 1, while pure water has a neutral pH of around 7.

Many common drinks have pH values between 2 and 4, making them highly acidic. This includes soda, juices like lemon and orange juice, vinegar, alcohol, and coffee. Prolonged contact with stainless steel causes corrosion accelerated by the acid.

The graph above showcases the pH values of ten popular drinks, arranged from lowest to highest pH. As depicted, lemon juice starts the scale with the lowest pH, indicating high acidity, while baking soda solution caps the chart with the highest pH, indicating alkalinity.

To avoid corrosion damage to your Hydro Flask, limit the long-term storage of acidic beverages inside it. If you regularly carry coffee or juice in your bottle, take care to wash thoroughly each day with a bottle brush and baking soda solution.

While occasional usage likely won’t harm your Hydro Flask, acids can still degrade the steel. So for daily carry, stick to less reactive liquids like water.

What Impact Do Energy Drinks Have on Hydro Flask Bottles?

The highly acidic nature and carbonation found in many energy drinks can damage Hydro Flask water bottles over long-term exposure.

In addition to having an acidic pH of around 3, popular energy drinks often contain carbonic acid from dissolved CO2. This combination subjects stainless steel to heightened corrosion.

Other reactive ingredients, like caffeine and herbal extracts, can also accelerate damage to the bottle’s interior. And since many energy drinks have very high sugar concentrations, they leave sticky residues that foster bacteria if not cleaned promptly.

So while giving your Hydro Flask an energy boost might seem appealing, take care to avoid making these beverages your daily carry. Limit contact to occasional, short-term usage only. And be diligent about thorough cleaning of your bottle afterward if storing energy drinks for any length of time.

Over prolonged exposure, the acidity, sugars, and other ingredients found in these turbo-charged beverages can pit, stain, crack, and degrade your Hydro Flask’s integrity. Stick to water or less reactive liquids for daily transport and storage.

Why Is It Not Recommended to Store Juice Concentrates in A Hydro Flask?

As the name implies, juice concentrates, like orange juice frozen concentrate, contain highly concentrated fruit acids and sugars. This intense mixture can seriously degrade stainless steel Hydro Flask bottles over time.

The typical pH of frozen juice concentrate sits around 3.5 to 4, many times more acidic than an orange itself. And the sugar content by weight can exceed 50 grams per serving once reconstituted.

This combination of dense acid and sugar is problematic for stainless steel. Together, they accelerate corrosion dramatically compared to a normal glass of orange juice. Extended storage of frozen concentrates in your Hydro Flask is sure to cause damage.

So while it might seem convenient to stash juice boxes inside your bottle, this practice is sure to void any warranty. Over time, corrosion will severely degrade the integrity of the steel.

For the sake of your bottle’s long-term durability, avoid using Hydro Flasks for storing juice concentrates or any other high-acidity liquids. Stick to less reactive beverages, like plain water, instead.

Can Storing Alcoholic Beverages in Hydro Flask Cause Issues?

Yes, the acidic and sugary nature of alcoholic drinks like wine, beer, and mixed cocktails can negatively impact Hydro Flask water bottles over time.

Ethanol itself (the alcohol) doesn’t react with stainless steel. However, most alcoholic beverages have an acidic pH under 4 due to various fruit extracts, sugars, and carbonic acid content.

Over prolonged storage, corrosion occurs due to these organic acids and sugars reacting with stainless steel. Pitting, cracking, staining, and strange residues or odors developing inside bottles are the results.

An occasional adult beverage stored briefly in your Hydro Flask likely won’t cause harm. But take care to avoid making spirits your daily habit with these bottles. Clean thoroughly after any alcohol use to avoid accelerated corrosion issues.

What Happens When You Put Very Sugary Drinks in a Hydro Flask?

While pure cane sugar itself has a neutral pH, many sugary beverages also contain fruit acids and carbonation that can still damage stainless steel. But even without other reactive ingredients, sugary liquids impact Hydro Flask bottles.

Highly concentrated syrupy beverages like sodas, sweet tea, agave nectar, and simple syrup leave sticky residues inside bottles. These cling to the steel walls and provide food for bacteria and mold if not cleaned promptly.

Over time, sugary buildup fosters corrosion, unpleasant odors, and permanent staining or hazing on the metal. It can also gum up moving parts around lids, seals, and handles.

So while your Hydro Flask’s stainless steel construction avoids retained tastes, sugary drinks still require special care. Be sure to clean your bottle thoroughly after each use if you are storing sugary beverages, even temporarily. Avoid leaving them sitting with residues overnight.

For daily usage, stick to lower-sugar liquids like lightly sweetened drinks. But expect to wash bottles more frequently to avoid sticky buildup when carrying sweeter drinks.

Are There Any Risks to Storing Tea or Coffee Long-Term in Hydro Flask?

Yes, the acidic nature of teas and coffee can degrade stainless steel Hydro Flask bottles over prolonged storage.

The typical pH of black tea and coffee sits between 4 and 5. Herbal teas can be less acidic, with green tea around pH 7. Overnight or repeated contact lets corrosion start through these organic acids.

And since tea and coffee both contain staining tannins, they can leave discoloration inside the bottle. This happens faster at higher temperatures, so take care when using Hydro Flask bottles as travel mugs.

For occasional tea or coffee transport, your Hydro Flask should be fine if promptly washed out. However, prolonged batch storage or steeping inside the bottle is problematic due to staining, buildup, and corrosion over time.

Why Should You Avoid Putting Perishable Liquids in Hydro Flask?

As touched on regarding dairy products, Hydro Flask’s excellent insulating properties can actually accelerate the spoilage of perishable liquids.

Without light exposure or significant air circulation, it’s difficult to monitor signs of spoilage in perishable beverages stored inside Hydro Flask bottles.

And unlike clear glass or plastic bottles, you can’t easily spot mold development or color changes that signal degradation. So even while kept chilled, contamination can happen unseen.

For brief transports under 6 hours, perishable items in your Hydro Flask likely won’t spoil. But take great care to avoid batch-storing these items for prolonged periods. If left sitting too long, foodborne bacteria can multiply to dangerous levels without you realizing it.

Stick to water or shelf-stable beverages for daily use. Only use Hydro Flasks for transporting perishable liquids meant for immediate consumption within several hours.

How Do Saltwater and Chlorinated Water React with Hydro Flask Bottles?

While pure water won’t react with stainless steel, saltwater, and chlorinated water can degrade Hydro Flask’s interior over time. The high salt content of ocean water, saline solutions, and mineral baths accelerates pitting and corrosion through electrolysis.

The chlorine in treated tap water and swimming pools removes the passive chromium oxide layer protecting stainless steel. This leads to etching, pitting, wear, and long-term damage to your bottle.

So while Hydro Flask excels at insulating drinking water, take care of other water sources. Avoid filling up directly from hot tubs, pools, or the ocean. Over time, corrosion will degrade performance and warranties can be voided.

If storing saltwater or chlorinated water in emergencies, promptly clean your bottle afterward with a baking soda solution to halt corrosive reactions. But for daily usage, stick to low-mineral freshwater to preserve integrity.

What Types of Liquids Can Cause Staining Inside Hydro Flask Bottles?

In addition to teas and coffee, as mentioned previously, many organic liquids can permanently stain the interior of Hydro Flask bottles:

  • Coffee & Tea: Stubborn tan tannin staining
  • Tomato Juice: Orange staining, difficult to remove
  • Berry juices: Blackberries, blueberries, and strawberries contain intense pigments.
  • Bright sodas: Colas, root beers, Dr. Pepper.
  • Balsamic vinegar: Pigment concentrates during the aging process.
  • Soy sauce: Caramelization causes stubborn staining.
  • Tomato sauce: Lycopene pigments bond tightly to stainless steel.
  • Wine: Tannins interact with steel, worse with reds.
  • Dark spirits: Whiskeys, cognac, and rum contain congeners that stain.

For each of the above liquids, staining typically appears as discoloration or hazing on the interior bottle walls. It develops quickest under warmer conditions, so staining accelerates when used as travel mugs.

While some staining is cosmetic only, often it correlates with accentuated corrosion as well. So avoid prolonged storage of pigmented liquids inside your Hydro Flask, even if you don’t mind some hazing. Over time, material breakdown continues beneath discoloration.

Promptly hand wash the bottle’s interior with a bottle brush after any staining or liquid usage to minimize lasting discoloration. But now some ghost staining may still persist and progressively develop the longer that type of liquid contacts the steel interior.

How to Clean Your Hydro Flask After Storing Strong-Smelling Liquids?

If your Hydro Flask takes on odors from storing pungent liquids like garlic oil, hot sauce, or pickle brine, don’t worry. While stainless steel won’t retain taste, some stubborn scents require extra cleaning effort.

For prompt cleanup after storing pungent liquids:

1: Handwash gently with a non-abrasive bottle brush

2: Use lukewarm water and mild dish soap—NO BLEACH

3: Rinse the bottle with a solution of equal parts water and white vinegar

4: Let the bottle thoroughly air-dry upside down

Skipping this gentle handwash protocol by throwing odor-prone bottles directly into the dishwasher can actually bake smells into the scratched-up surface and bind stains into etching.

First, hand wash the bottle soon after use with warm, soapy water. This prevents residue from building up where smells originate. Ensure you use a bottle brush to fully contact all interior surfaces, especially around obstructed areas near lids and stops.

If scents linger after an initial wash, do a deeper cleaning by filling your Hydro Flask with warm water and denture cleaner tablets. After sealing the lid tightly, let it soak overnight. The powerful enzymes in denture cleaners help eliminate difficult organic odors that simple soap can’t tackle.

For the most stubborn scents, like garlic, try this soaking method but use a baking soda solution instead of denture tablets. Fill the bottle fully with a few tablespoons of baking soda and some warm water, close it, and soak it for 8 to 12 hours for maximum odor neutralization.

Can the Warranty Be Voided by Storing Prohibited Liquids in Hydro Flask?

Yes, the limited lifetime warranty from Hydro Flask specifically excludes damage caused by storing non-recommended liquids for prolonged periods.

Their website states the warranty does not cover damage caused by “improper use or misuse of the product.”. So you risk voiding coverage if caustic liquids degrade the bottle to failure.

Examples would include permanent staining or corrosion holes forming after repeated storage of wine, juices, or chlorinated water over time. Since the warranty excludes such chemical damage, take care of liquid storage choices and durations.


While Hydro Flask excels at insulating water and less reactive beverages, take care when storing other drinks long-term. Many common liquids can corrode, stain, or degrade stainless steel over repeated contact.

Limit acidic, sugary, carbonated, fermented, chlorinated, and perishable liquids to brief, occasional usage. And promptly wash bottles afterward to contain any reactions. For daily transport and storage, stick to safe choices like plain, fresh water.

By understanding which liquids to avoid putting in your Hydro Flask regularly, you’ll protect its integrity for years of enduring performance. Take a few precautions with storage choices and cleaning habits, and your bottle should last a lifetime.


Q: Does stainless steel affect milk taste?

A: No, the Grade 18/8 stainless steel used in Hydro Flask won’t alter tastes. But take care to avoid prolonged batch storage of perishable dairy products.

Q: What liquids can I store long-term in my Hydro Flask?

A: For indefinite storage, stick to safe choices like plain, purified water and lightly sweetened drinks under 10 grams of sugar per serving. Minimize acidic, sugary, carbonated, or reactive liquids.

Q: How do I clean the dye staining inside my bottle?

A: Dye stains can bond tightly and resist removal even with aggressive scrubbing. Try using a water bottle cleaning tablet and letting it soak overnight. However, some faint residual staining may still remain afterward. Prevent it by promptly washing after any dye contact.

About Me

I’m Paul Burkhardt, an expert in water and water treatment since 2006 with in-depth experience not only in treating water but also in helping to provide people with healthier, high-quality drinking water.

I’ve helped thousands of people with their drinking water questions, including what kind of water bottle might be best for them and their lifestyle.

If you’d like more information about me, please check out the links below or read more here:

Paul Burkhardt

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