Your Hydro Flask keeps your drinks cold for hours, but without regular cleaning, it can quickly become a breeding ground for bacteria, mold, and odors. Whether you use it for water, coffee, or smoothies, maintaining your Hydro Flask ensures every sip tastes fresh. In this guide, you’ll learn how to clean your Hydro Flask daily and how to deep clean it with vinegar or baking soda for tougher stains and smells.

Why Cleaning Your Hydro Flask Matters

Hydro Flasks are made from stainless steel and designed for long-term use, but bacteria can build up—especially under the lid and around the rubber seals. Regular cleaning prevents:

  • Mold growth and unpleasant odors

  • Metallic or stale taste in water

  • Stains from coffee, tea, or juice

  • Damage to the flask’s stainless steel interior

Experts recommend cleaning your Hydro Flask daily with warm, soapy water and doing a deep clean at least once a month.

Method 1: Washing with Dish Soap (Daily Cleaning)

Step 1: Disassemble Your Hydro Flask

Remove the lid, straw, and any detachable parts. Cleaning each component separately helps eliminate hidden bacteria buildup, especially around seals and spouts.

Step 2: Wash Each Part Thoroughly

Use hot, soapy water and a bottle brush to clean the inside of your flask. A baby bottle brush or Hydro Flask cleaning brush works best for reaching the bottom.
Avoid soaking the lid for too long—it can trap water inside and grow mold.

Pro Tip: Use a small brush or pipe cleaner to scrub straws and tight spaces where residue collects.

Step 3: Rinse Thoroughly

Rinse all parts under warm running water to remove every trace of soap. Leftover soap can affect taste and leave residue inside the bottle or straw.

Step 4: Use a Dishwasher (Optional)

Only certain lids—like the Hydro Flip and Wide Straw Lid—are dishwasher safe. Wash other parts by hand to extend their lifespan.

Step 5: Air-Dry Completely

Let every part dry completely before reassembling. Place the bottle upside down on a drying rack overnight to prevent trapped moisture and bacteria growth.

Method 2: Deep Cleaning with Vinegar (Disinfect and Deodorize)

If your Hydro Flask has a sour smell or mold buildup, vinegar is a safe and natural disinfectant.

Step 1: Add Vinegar

Pour ½ cup of distilled white vinegar into your Hydro Flask and swirl gently to coat the interior. Let it sit for 5–10 minutes.
Alternatively, mix one part vinegar with four parts water and leave overnight.

Step 2: Scrub with a Bottle Brush

Use a long brush to reach the bottom and corners of the flask. Vinegar breaks down bacteria while the brush removes sticky buildup.

Step 3: Rinse Well with Warm Water

Rinse thoroughly until the vinegar smell disappears. This may take two or three rinses.

Step 4: Air-Dry Upside Down

Let your Hydro Flask dry naturally upside down on a dish rack. Proper drying prevents new bacteria from forming.

Method 3: Removing Stains with Baking Soda

Baking soda is perfect for removing stubborn stains and lingering odors caused by coffee or tea.

Step 1: Make a Baking Soda Paste

Mix 2–3 tablespoons of baking soda with a small amount of warm water to create a thick paste.

Step 2: Scrub the Flask

Dip your bottle brush in the paste and scrub the inside thoroughly using circular motions. Focus on stained areas.

Step 3: Rinse Until Clear

Rinse with warm water multiple times until no baking soda residue remains.

Step 4: Air-Dry

Place the bottle upside down or at an angle to ensure complete airflow and dryness.

Extra Tips for Maintaining Your Hydro Flask

  • Avoid bleach or chlorine: These can damage the stainless steel.

  • Don’t soak the lid for long periods: It can cause mold around the rubber seal.

  • Never freeze or microwave your Hydro Flask.

  • Store with the lid off: Prevents trapped moisture and odors.

Conclusion

Cleaning your Hydro Flask regularly not only keeps your drinks tasting great but also protects your health. With a little soap, vinegar, or baking soda, you can easily remove stains, odors, and bacteria—ensuring your favorite bottle stays fresh and ready for your next adventure.