Seven Thermos Bottle Mistakes That Could Pose Health Risks

A thermos bottle has become a popular and handy companion for daily hydration. However, there are mistakes in using this familiar device which could turn the convenience into a health hazard. Let’s discover the following seven common mistakes and ways on using the bottle safely and effectively 

Extended Storing of Perishable Liquids 

Milk, soup or other perishable liquids should not be kept for hours in a thermos bottle. While the flask retains the liquid temperature well, the sealed environment can encourage bacterial growth once the heat drops below safe levels. For dairy-based drinks or broth, consume them within the first four hours and clean the bottle immediately afterward. 

Improper Cleaning  

Thermos bottles must be cleaned thoroughly after every use. Failing to do so can lead to mold, bacterial buildup, and bad odors. Especially with narrow-mouthed models, residue can hide in crevices. 

 Use warm soapy water, a bottle brush, and let the bottle dry completely before sealing. Deep-clean with baking soda or vinegar weekly. 

Keeping the thermos bottle clean and safe is the right way to protect user's health 

Storing Wrong Liquids 

Avoid keeping carbonated drinks, dry ice or acidic juice in thermos bottles unless the product explicitly allows it.  

Pressure buildup from carbonation or corrosion from acidic liquids may damage the bottle’s internal structure or cause leaks and injuries. 

Microwaving or Dishwashing When Not Allowed 

Thermos bottles, especially those made of stainless steel, should never be microwaved. Doing so can cause sparks or permanent damage.  

Besides, unless labeled “dishwasher safe”, washing in a dishwasher can weaken seals or warp plastic parts. Always follow the manufacturer’s care instructions. 

Drinking Without Spoilage Check 

Some users assume that liquids inside a sealed thermos are always safe. However, even if the bottle feels warm, the contents may have dropped below food-safe temperatures.  

Always check smell and taste before consuming, especially when dealing with milk or protein-based drinks. 

Warm moments start with clean, properly used thermos bottles. 

Ignoring Damaged Seals, Cracks 

A worn-out rubber seal or a crack in the lining can compromise thermal insulation and harbor bacteria. If users notice leaks, difficulty closing the lid, or sudden loss in temperature retention, it’s time to inspect or replace the bottle. 

Skipping Preheating/Pre-cooling 

A small but significant mistake is filling the bottle directly with hot or cold liquids without pre-conditioning it. Pouring boiling water into a cold thermos may lead to uneven insulation and thermal stress.  

Pre-warm or pre-cool the bottle with similar temperature water for better results and durability. 

Choose Trusted Brand  

Safe hydration starts with quality thermos bottles produced by Vietnam's Rang Dong 

Using a thermos bottle correctly means not just convenience, but also safety. The thermos bottles made by Rang Dong, Vietnam’s leading manufacturer of vacuum flask products, are designed with premium stainless steel, BPA-free lids and reliable thermal insulation that meets international safety standards. With more than six decades of experience, the Hanoi-based company now delivers products trusted by millions worldwide. 

Should you have any questions or request a quotation of Rang Dong products, please send us an email to: export@rangdong.com.vn. 
Websites: en.rangdong.com.vn and vacuumflask.rangdong.com.vn