Whether you’re drinking homemade hot tea in your office or taking warm soup to a sick friend, a thermos is always our best buddy during winter.

However, while enjoying your thermos, it’s important to use, clean, and store it correctly, so you don’t damage your favorite product. So, can you wash a thermos in the dishwasher? The short answer is: it depends.

your thermos is dishwasher safe depends on the type of thermos you use.

Can Thermos Go In The Dishwasher?

Dishwashers have made our lives easier. Rather than scrubbing soap aggressively, you can now simply throw your dirty dishes in the dishwasher. Dishwashers are designed to thoroughly clean dishware, cookware, and all sorts of cutlery.

It uses hot water and often a strong detergent that may damage certain items that are not dishwasher safe. Whether your thermos is dishwasher safe depends on the type of thermos you use.

Thermoses that can go in the dishwasher

All metal utensils are dishwasher safe. If your thermos or flask is made out of stainless steel, you can definitely throw it in the dishwasher without any fear of it sustaining damage.

However, the polish of a stainless steel thermos may wear off if you use hard water (water with high mineral content) or an aggressive detergent. If you have a plastic thermos, you can also put it in the dishwasher.

Thermoses that can’t go in the dishwasher

Thoroughly read through the care instructions found on a pamphlet in your thermos packaging or on your thermos website to find out if your Thermos is dishwasher friendly. However, generally, while metal thermoses are dishwasher safe, glass thermoses are not.

A glass thermos may have a stainless steel exterior or a glass wall exterior. Always look at the interior tumbler to know the type of thermos you have. Delicate glass thermoses also have the risk of breaking from the high water pressure inside a dishwasher.

You may notice yellowing or etching on your glass thermos from cloudiness or from a strong detergent, after washing your thermos. Use distilled white vinegar to remove any stains on the glass after washing it in the dishwasher. 

Why Is Thermos Not Dishwasher Safe?

A thermos has insulated walls to prevent heat from escaping. Dishwashers use hot water to effectively scrape off food from your dishes by breaking it down. Using hot water also minimizes the water residue and cleans better, so your dishes are spotless and shiny.

However, hot water can also melt or burn the vacuum seal and break it, allowing air to seep in. Once your Thermos fills up with air, it will not insulate properly, allowing heat to escape.

Washing your dishes or thermos in a dishwasher may be convenient, but often, dishwashers become home to many pathogens. These microbes stick to your Thermos and can make you sick while you use them. Regularly cleaning a dishwasher is crucial!

Which parts of the Thermos are dishwasher safe?

Whether you have a glass, stainless steel, or plastic thermos, it is likely that the lid of your Thermos is made of plastic and rubber. Thermos lids are entirely dishwasher safe, but they must be placed on the topmost rack of your dishwasher.

The heat from the hot water in a dishwasher can make the plastic lid warp. To prevent warping, always place plastic or rubber items on the top rack since the heater is usually placed at the bottom of the dishwasher.

Thermos tumblers are dishwasher safe if they are made out of plastic or stainless steel. Wash the straw by hand.

After washing your thermos lid in the dishwasher, there is always the struggle of how to put the lid back together. Insert the bottom piece of the lid into the top piece while making sure that you press down on the handle or button and turn the lid clockwise.

What happens if you put a Thermos in the dishwasher?

It is generally recommended to handwash thermoses, even those that are dishwasher-friendly. Is a thermos travel mug dishwasher safe?

Well, hot water in a dishwasher may damage the insulation of your thermos. A travel thermos is not very airtight, and a dishwasher may be too harsh for it. When water enters the insulated wall of the thermos, the insulation seal breaks and permanently damages your thermos.

A thermos keeps beverages warm by creating a vacuum between two walls. The vacuum does not allow heat from the beverage to escape. Beverages in a thermos get cooler after some time because they lose heat from the lid, not from the walls.

Water pressure inside the dishwasher may dislodge the tumbler inside. This will not only damage the vacuum seal but also make your thermos more prone to getting food residues stuck in it.

The shine and paint of the Thermos may also wear off if the bleach or detergent you use is strong. The powder coat on a stainless steel thermos can easily get discolored by hot water.

If you have been using a dishwasher for some time now, you must have found mold collecting on your plates, pots, and pans washed in it. Similarly, mold can also collect on a thermos. Residual food can get stuck in the lid.

Or if your thermos comes with a metal straw, there is a high chance of mold accumulating in there. To remove mold, gently peel it off with your hands or scrub it with a sponge, dishcloth, scrubber, or steel wool.

The best way to remove mold is to avoid it in the first place. Keep your dishwasher clean and fresh with vinegar and baking soda to avoid mold spores.

Is Thermos FUNtainers dishwasher safe?

A damaged straw may make your FUNtainer leak.

The FUNtainer beverage bottle is very popular amongst children. It has only four parts that are easy to clean and assemble. All four parts can be placed on the top shelf of a dishwasher. However, to maintain quality, it is best to wash it by hand.

While handwashing, avoid scrubbing too hard as it may dull or damage the outer furnish. Abrasive cleaners, bleach, or cleaners with chlorine can also damage your thermos. Rinsing with soapy water is enough to clean a thermos.

To maximize the efficiency of a FUNtainer beverage bottle, fill it with cold tap water and put on the lid. Let your bottle stay this way for 5–10 minutes before you drain out the water and use it. The FUNtainer, like most other beverage bottles, is leakproof.

Make sure you fasten the lid properly and lock it. A damaged straw may make your FUNtainer leak. Regularly check if your straw has worn out and immediately replace it to avoid any leakage. The straw is dishwasher-friendly, but it is recommended that you hand wash it.

Are Soup Thermos Dishwashers Safe?

A soup thermos is a wide-mouthed thermos, usually made out of stainless steel. For thermal efficiency and to avoid any leakage, tightly fasten the lid of your soup thermos. If your soup thermos is made out of stainless steel, it can be washed in the dishwasher without being damaged. Like all other thermoses, it is recommended to hand wash a soup thermos.

Are Thermos Flask Dishwashers Safe?

A thermos flask is very useful for storing and carrying foods and beverages. Thermos flasks come in glass, plastic, metal, and steel.

The insides are usually made out of glass or metal, and the outside is made out of plastic or steel. Most flasks are dishwasher-friendly. However, avoid washing a flask that has a glass tumbler.

Can A Stainless Steel Thermos Go In The Dishwasher?

While aluminum or any non-stick bakeware can not go in the dishwasher, stainless steel is dishwasher-friendly. However, stainless steel thermoses have a powder coat finish that gives them color and shine.

Harsh detergent in a dishwasher can dull the shine or even wear it off, while hot water can discolor the powder finish. It is advisable to handwash stainless steel thermoses with non-abrasive soap. 

Stainless steel can be corroded by heat and harsh detergents. Make sure you place your stainless steel thermos in the top rack and don’t add any strong detergent. Food soils often becomes acidic, which can corrode the tumbler and walls of your thermos.

Rinse your dishes and thermos with plain water before putting them in the dishwasher to avoid corrosion and to avoid any microbes harvesting in your dishwasher.

Rinsing beforehand also helps keep your filter baskets from being clogged. After some time, your stainless steel thermos will likely lose its shine if washed in a dishwasher. Keep reading to find how you can recover a dull stainless steel thermos.

Can A Kids’ Thermos Go In The Dishwasher?

Kids’ thermoses like the YETI are made out of stainless steel, which is entirely dishwasher safe. The YETI is specifically designed to be dishwasher safe and can withstand its heat.

Not only will the exterior not be damaged, but the usability of your thermos will not change. Over time, the use of a dishwasher will not affect the insulation of your YETI. The vacuum seal of a YETI can withstand high temperatures. Water pressure will not dislodge the tumbler.

Can damage from the dishwasher be recovered?

Most damage from dishwashers can be reversed; it depends on the nature of the damage. Dishwashers turn aluminum grey and spongy, but scrubbing with tartar cream restores the original color and shine.

To restore the shine of stainless steel, rub and clean with vinegar. You can find many sprays in stores that can polish stainless steel thermoses.

If your plastic lid has been deformed from the heat, unfortunately, it can not be restored, and you will have to replace your thermos lid. Corroded or rusty metals can be restored by scrubbing with baking soda or hydrogen peroxide.

The best remedy is to avoid damage. Do not put any item in a dishwasher if it is not specifically designed to withstand the heat and detergent.

To check if your flask or thermos is dishwasher safe, look for a symbol on the product or a label that says dishwasher safe. If your thermos contains anything that has a low melting point, it is not dishwasher safe.

Other ways to wash a thermos

Use a non-abrasive soap to gently clean your thermos. Scrub with your hand or with a soft cloth to remove any stains. If your thermos is smelly or has hard stains, pour half a cup of vinegar into it and fill the rest of the thermos with hot water.

If your thermos is made of stainless steel, add half a tablespoon of baking soda as well. Let your thermos sit like this, without its cap, overnight, and then rinse it with water. Generally, you will not need to do this if you regularly wash your thermos with a mild detergent.

Are Thermos Dishwasher safe

Wraping it Up : Are Thermos Dishwasher Safe?

Are Thermos Dishwasher Safe? Thermos products are mostly dishwasher safe, but it is recommended to wash them by hand nonetheless. Handwashing retains the shine and beautiful finish of your thermos. Dishwashing may be helpful at times, but over time it can damage your thermos.

Insulation keeps a thermos functioning, and if your thermos is not very structurally tight or if the vacuum seal is made out of plastic that has a low melting point, it is perhaps best to avoid putting your thermos in the dishwasher.

The top rack of a dishwasher is designed for items that cannot withstand heat. If you must put your thermos in a dishwasher, use the top rack.

Most damage from washing in a dishwasher can be easily recovered from home remedies. Hand wash your thermos to avoid any potential damage and to keep it shiny and beautiful.

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