How To Clean A Coffee Thermos? (Helpful Tips)

Last Updated on May 1, 2022 by John Moretti

Keeping coffee hot on the go or while commuting is a big priority for many coffee lovers. The preferred method of keeping coffee hot on the move is to use a coffee thermos, but everyone who has used this type of vessel knows that keeping a coffee thermos clean can be a challenge. What is the best and simplest way to clean a coffee thermos?

The best way to clean a coffee thermos is to wash it in hot water with dish soap immediately after use. Be sure to remove all detachable components of the thermos before washing to ensure that there are no remnants of coffee or dairy products left behind to spoil and ruin the vessel. 

Cleaning a coffee thermos can be a challenge, but keeping these vessels clean is the only way to ensure that they can be reused for a long while before requiring replacement. If you take care of your thermos, you will get many years of safe use from it. Let’s explore the best ways to clean a coffee thermos.

How To Clean A Coffee Thermos

Cleaning a coffee thermos can be a challenging process, especially if the thermos is a strange shape, if it is made from several different materials, or if the thermos has heating elements and smart-thermos features.

However, there are some simple procedures to follow to clean any type of thermos, so long as the thermos is cleaned soon after finishing the coffee. The most important aspect of cleaning a thermos is to not allow any coffee to remain in the vessel for extended periods, as this will ruin the thermos beyond all cleaning.

To clean a coffee thermos, the first step is to remove the lid and any other detachable components of the vessel. Most coffee thermoses are made from stainless steel, which is a very durable and easy to clean material.

Photo of coffee pouring into a white cup from a thermos

The simple process of cleaning the thermos must always involve hot water and dish soap. Once the thermos is disassembled, immerse all of the components of the vessel into hot, soapy water. Allow the thermos to soak for a few minutes before continuing.

After soaking for a short while, use a sponge or a dish brush to thoroughly clean the inner surfaces of the thermos and all of the detachable components. Be sure that there is no residue left within the thermos before you move on.

Once the thermos has been scrubbed clean, run the vessel and its components under cold water to remove the dish soap. Be sure that no soap is left behind to contaminate your next brew.

When the thermos has been thoroughly cleaned and rinsed, allow the vessel and its components to air dry completely before reassembling the thermos. This ensures that no hazardous bacteria or mold is allowed to grow on any of the surfaces, keeping the thermos safe for use.


If the thermos has a faint smell of coffee after washing, the thermos is still safe to use.

However, if the thermos has an aroma of milk or spoiled milk, the thermos has not been cleaned well enough. Do not use a thermos that smells of spoiled milk, but rather wash the thermos again, being sure to reach every crevice and component of the vessel.

Is Your Thermos Dishwasher-Safe?

Photo of a dishwasher with dishes in the tray

One of the simplest ways to clean a coffee thermos is to run it through the dishwasher. However, not every thermos is safe to clean in a dishwasher, so be sure to check if your thermos is suitable for this cleaning method.

All single-walled stainless-steel and ceramic coffee thermoses are suitable for dishwasher cleaning unless the thermos has any smart features or electronics. Smart thermoses may not be dishwasher safe, but it is always best to check the manufacturers’ instructions to be sure.

Plastic coffee thermoses and bamboo coffee thermoses are not suitable for the dishwasher. The high temperatures of a dishwasher cycle will break down these materials and ruin the thermos entirely.

A coffee thermos that has any stickers or branding on it may not be suitable for the dishwasher either. The branding or stickers may be removed by the dishwasher cycle, ruining the thermos.

With all of that said, if your thermos is dishwasher-safe, running it through the appliance is the best way to clean the vessel. The high temperatures and effective cleaning ability of a dishwasher will kill all present bacteria and remove any unpleasant odors in the process.

Beware Of Detachable Components

Image of bacteria and fungi seen in petri dish

Most modern coffee thermoses are complex vessels that have detachable components. When washing a coffee thermos, these detachable components must be carefully considered. If these components are not cleaned well, they may grow dangerous bacteria.

When cleaning a coffee thermos, be sure to remove all detachable components and wash them individually. These components include the lid, any gaskets or seals present in the thermos, and all external grips and heat protectors.

These components are easy to miss, but if they are not removed before washing, they are likely to grow mold or harmful bacteria, and they may retain unpleasant odors as well.

Maintaining Thermos Cleanliness

Image of the thermos and the cap held by hands over a sink with soapy water

The best way to clean a thermos is to clean it as soon as you are finished using it. Keeping a thermos clean is much easier than cleaning a thermos that has become so dirty that it cannot be used.

Coffee thermoses are very difficult to clean when they have had coffee left in them for a long while, especially if that coffee was mixed with milk or cream. Any dairy products left in a coffee thermos, even very small amounts, are likely to spoil, smell foul, and even be harmful to your health.

This means that the best way to maintain and clean a coffee thermos is to clean the vessel before any remaining contents are allowed to dry. If you don’t have the time to wash the thermos right away, try to place the thermos in a sink or bowl of warm soapy water to begin the cleaning process.

This will prevent the thermos from growing any harmful bacteria, and it will rinse off any remaining liquids from the vessel and its components, making it much easier to clean properly when you are ready.


Phot of a coffee thermos separated in 3 parts

Cleaning a coffee thermos can be a challenge, but it is important if you want to continue to use the thermos safely without ingesting any harmful bacteria and without smelling any abrasive aromas.

The best practice for cleaning a coffee thermos is to keep the thermos clean and clean it immediately after use rather than allowing the contents to dry within the thermos. If the contents dry in the thermos, they can be difficult to clean, or they may ruin the thermos entirely.