Costco Hydro Flasks – List of the Top 4

If your job is desk-duty and the closest wilderness is on your screen saver, it has never been a better time to get out there.

Whether you spend time paddling up a river under cascading waterfalls, or a mountain bike trek past herds of elk and bison in the wilds of Montana, there are a few must-have essentials to take with you on the trip.


Hydration is one of the most, if not the most, important consideration on an outdoor adventure. Symptoms of mild dehydration such as a dry mouth, feeling tired and sleepy with a headache, can quickly worsen. Dizziness and difficulty in walking followed by rapid heart rate, fever, and even seizure can occur. The problem is you may not be aware of these symptoms until extreme when the damage is done.

Depending on how steep the mountain, or how wide the ocean kayak crossing, physical exertion can see a 2% loss in overall body weight. More than that and you will in all likelihood be in trouble.

Start all activity well hydrated. Have a plan for drink breaks based on sweat rates. You need to replace lost fluid during and after the exercise for up to 6 hours, drinking around 43 ounces.

On the market today is a variety of drink bottles and flasks to keep fluids hot or cold. Invented by Scottish scientist Sir James Dewar in 1892, he discovered a brass chamber enclosed by another chamber, sealed at the top, with partly evacuated air between the two, kept fluid at a constant temperature.

Our Costco Favorite

Takeya 40oz Stainless Steel ThermoFlask®, 2-pack

There is much to like about the Takeya ThermoFlask®. At 40 ounces it is among the biggest in the range, not to mention possibly the best value flask available. It comes in two colors: stainless steel and navy blue.

  • Double-walled vacuum insulated: Two walls of stainless steel stops heat from the outside warming liquid inside via conduction. A tight cap stops air from entering the flask transferring heat via convection. The same works in reverse in keeping heat from hot fluids escape via conduction. The double-walled construction also stops condensation forming on the outside surface of the flask making it clammy to hold or just plain wetting adjacent areas in a backpack.
  • 18/8 stainless steel construction: stands for 18% chromium and 8% nickel. 18/8 stainless steel is an industry standard when it come to food-grade hygiene. An important element in food container design is flavor contamination—today's medium roast coffee does not want yesterday's lime-flavor sport's drink. Professional food-grade stainless steel protects against flavor transfer.
  • Wide mouth for adding ice-cubes: Takeya says drinks will stay cold for up to 24 hours. In those times when hot beverages are preferred, drinks stay hot for 12 hours. A flask with a wide mouth also allows easier cleaning, a must for food hygiene.
  • Leak-proof twist cap: a cap that prevent heat from the outside getting in, or heat from a liquid escaping to the outside is essential in maintaining temperature. Takeya has a patented leak-proof lid. Many flask on the market require you to unscrew the drinking cap, or pull it open with your finger nail. Takeya 40 ounce stainless steel flask has a drinking spout with a flip top lever. It means joggers, cyclists, or off the beaten track holding a trekking pole, allows you to drink from the flask one-handed.

Takeya 40oz Stainless Steel ThermoFlask

Our Top 3 Amazon Favorites

Hydro Flask - Water Bottle/Travel Coffee Mug

  • 12 oz handy size
  • Wide mouth opening
  • Double-walled insulation
  • Hot up to 6 hours, cold 24 hours
  • Durable, sweat free powder coated finish
  • PBA free
  • 18/8 stainless steel
  • Compatible lids: Hydro flask Straw Lid and Flex Cap
  • Hand wash with soapy water
  • Choice of 9 colors plus stainless steel

Hydro Flask Travel Coffee Mug

Hydro Flask - Wide Mouth with BPA-Free Straw Lid

  • Hydro Flask support the development of public green spaces
  • Two sizes to choose from 32 ounce and 40 ounce
  • Hydro Flask support the development of public green spaces
  • ​Personalize you drink bottle with a number of color choices
  • ​Hydro Flask Straw Lid giving easy access to drinks on the go, whether jogging or driving
  • ​Proprietary Powder Coat gives a slip-free grip. Also adds durability for tough conditions.
  • 18/8 stainless steel for purity and strength
  • TempShieldTM prevents heat transfer with insulated technology

Hydro Flask Wide Mouth with BPA Free Straw Lid

Hydro Flask - Standard Mouth w/loop Cap

  • Wide choice of colors
  • Double-walled vacuum insulated. Cold drinks up to 24 hours, hot up to 6 hours
  • 18/8 stainless steel. Have no liner and BPA free
  • Powder coated matte finish never sweats or leaves puddles on the office desk
  • Lifetime warranty

Hydro Flask Standard Mouth with Loop Cap


Isn't this just another piece of junk carried around? Why should I buy one and not drink out of a plastic bottle like most folks?

The important aspect in keeping hydrated is to drink often. A plastic bottle will not keep water icy cold for long. Luke warm water is not good to drink in hot weather, while plastic gives water an unpleasant taste. Plastic bottles contain BPA (bishphenol-A). Although the jury is out as to damaging health affects, its use is restricted in the EU, Canada, China, and Malaysia. Vacuum flasks made with stainless steel are healthier options.

I can't understand how a thin bit of steel will keep a drink cold in my tractor, especially down in Texas?

It is not so much the stainless steel that keeps drinks cold, but rather the vacuum enclosing it. Heat radiates from the sun. Hot air carries heat via convection. A surface hot air contacts is warmed via conduction. While metal outside the flask will heat up, in a vacuum there is no air to transfer heat. The interior wall stays cold, so too does your drink.

I bought another brand of water bottle, and although it did the job, left a pool of water in my car, the outside sweated big time. Won't a Takeya ThremoFlask do the same thing?

The reason why pop bottles and beer cans sweat is because vapor in the air lands on a cool surface. The gaseous water vapor reverts back to water in the form of droplets. A Takeya ThermoFlask has a vacuum insulated layer. It means the cold part is inside while the outside is the same temperature as the air. Water vapor stays away.