How to Get Coffee Smell Out of Thermos (11 Cool Ways Explained)

How often do you find your coffee thermos reeking of old or stale coffee?  It can make your next cup of coffee out of the thermos taste not so good. If you are using a coffee thermos regularly to keep your coffee hot or during a day long trip, you do not want to end up with a sip of really bad tasting drink.

I’ve tried the following 11 ways and found they work great to get coffee smell out of thermos: baking soda and water, vinegar and baking soda, apple cider vinegar, denture tablets, anti-acid tablets, a combination of bleach and water, ice and salt, dishwasher detergent, paper towels, mustard powder and sour salt.

These ideas will also keep your coffee thermos in good nick so you can keep on using it for many years. Let’s talk how each one works so you can pick the most convenient for you.

11 Cool Ways to Remove Odor from Your Coffee Thermos

1. Add Some Freshness: Baking Soda and Water

Baking soda can clean just about everything and does an excellent job of removing odors. Rinse out the thermos with hot water. Pour more hot water into your thermos to three-quarters full and add two tablespoons of baking soda for every two cups of water in the thermos.

Leave it to sit a few hours or even overnight. You can then pour out the baking soda and water mix and rinse well with clean water a few times. Your thermos will not only smell fresh but all the stains will be removed too.

2. Fizzle Away the Odor: Vinegar and Baking Soda

This may sound more like a science lab experiment but it works! Grab some white vinegar, approximately half a cup and pour into the bottom of the thermos. Add two tablespoons of baking soda. This is when the fizzling will happen so make sure you’re holding the thermos over the sink for any overflow. Top up with boiling water.

Let the mixture sit in the thermos for a few hours (overnight is better). Do NOT place the cap on the thermos. The next day, empty the vinegar, baking soda, and water out. Rinse the thermos thoroughly to remove any traces of vinegar smells.

3. Vinegar or Apple Cider Vinegar? Both Ways Work

White vinegar or apple cider vinegar mixed with hot water works well in removing any stale coffee odor from your thermos. Pour half a cup of your choice of vinegar into the bottom of the thermos. Top up with hot water, place the lid on and give the thermos a couple of shakes. Let the thermos sit for a few hours and then pour out. Rinse it under the tap a few times to remove any vinegar smells.

A nifty idea for removing vinegar smells is to add some vanilla ice cream after you’ve rinsed out the vinegar and water mix. Let the ice cream sit in the thermos for a few hours. Wash out with warm soapy water and your thermos will no longer smell of stale coffee or vinegar. Instead, you’ll get hints of vanilla wafting out of your thermos whenever you open it!

4. Grab Grandpa’s Denture Tablets

Who would have thought denture tablets would have more than one purpose? Well, they’re excellent for removing smells AND stains from your coffee thermos. Follow the steps below to get your thermos odor-free once more:

• Grab two denture tablets from Grandpa’s medicine cupboard and toss into your thermos.
• Sit your thermos in the sink and add water. The mix will start to fizzle and possibly overflow.
• Let the denture and water mix sit in your thermos overnight.
• In the morning, toss out the mix and give your thermos a good wash with hot soapy water. Rinse out well, wipe with a towel and leave to air dry.

Your thermos will be as sparkling as Grandpa’s dentures and smell fresh too! Plus, your thermos will be free of any bacteria buildup.

5. Antacid Tablets Will Remove Any Odors

Antacid tablets are good for balancing the acid in your stomach giving you relief after rich meals. Your coffee thermos may not be full of acid but you can still use antacid tablets to remove smells and stains.

Add four antacid tablets to your thermos and fill with water. Place the lid on and give a few shakes to ensure a good mix. Leave to soak for at least one hour. Rinse it out well and leave it to air dry.

6. Bleach Out Any Odor

A combination of bleach and water is an effective and quick way to remove smells from a thermos. Use the following steps to help you clean your thermos:

• Pour ¼ to ½ cup of bleach into the thermos.
• Add hot water and mix well.
• Leave to soak for 30 minutes to one hour.
• Toss out the bleach and water mix and rinse well.
• Wipe with a towel and leave to air dry.

Always make sure your rinse the thermos well after using bleach so you’re not left with a taste of bleach in your coffee the next time you use your thermos.

7. Scrub Away Odor With Ice and Salt

While this method may take some preparation from your side, it’s worth doing it. Crush enough ice to half fill your thermos. Add two to three tablespoons of table salt to the ice. Place the lid on the thermos and shake it a few times. This will cause the ice and milk to “scrub” the inside of the thermos. It’ll effectively remove any grime and odor.

Throw out the ice and salt and rinse well. Leave to air dry.

8. The Conventional Way: Good Ol’ Dishwasher Detergent

If you’re vigilant about cleaning your thermos after every use you shouldn’t battle with an odor problem. Once you’ve finished drinking the coffee out of your thermos, give it a good clean with hot water and dishwasher detergent. Use a bottle brush to thoroughly scrub the inside of your thermos, getting into all the little corners you can’t normally reach with your hand. Rinse well and leave to air dry.

Thermos users have also found adding a tablespoon of automatic dishwasher powder to their thermos and topping it with water works well. Leave it to sit for one hour or so and then wash out with clean water.

9. Soak Away Odors with Paper Towels

Most kitchens will have a roll of paper towels on hand. Give your thermos a good wash with hot soapy water and wipe dry with a dishtowel. Place a few squares of paper towels into the thermos and put the lid on. The paper towels will absorb any smells in the thermos. Remove the paper towels after they’ve been in the thermos overnight or longer.

10. Deodorizing Spice: Mustard Powder to the Rescue

Mustard powder is highly effective in removing odors from your thermos, dinner plates and even your hands. The following steps will show you the best way to use mustard powder to remove smells from your thermos:

• Make a paste with one tablespoon of mustard powder and water in the thermos.
• Use a bottle brush to scrub the paste around the inside of the thermos leaving a layer of the paste on the internal coating of the thermos.
• Place the lid on the thermos and leave to sit for about eight to ten hours.
• Rinse out thoroughly with hot water. As the paste can be sticky you may need to use the bottle brush again to remove the layer of paste.
• Wipe and leave to air dry.

While this method may be a bit labor-intensive, if you’re really battling to rid your thermos of bad smells mustard powder may be your best solution.

11. Sour Salt: The Citric Acid Solution

Citric acid powder is a natural product made from citric fruits. It looks like salt which is why some people refer to it as “sour salt”. It’s a very good way of cleaning your thermos and ridding it of unpleasant smells without you worrying about any toxic chemicals. It is used as natural descaler for coffee makers as well.

Add a tablespoon (or more if your thermos is extra-large) to your thermos and fill up with boiling water. Allow it to sit for up to two to three hours before emptying out. Rinse well, wipe dry and leave to air dry without replacing the lid.

Good Maintenance Tips

The best way to keep your thermos odor-free is to make sure you always keep it clean after every use. Use the following tips to keep your thermos well-maintained:

1. Always wash the thermos with hot water and dishwasher detergent after every use as soon as possible. The longer you leave it without cleaning the more likely odors and mold will build up.
2. Let the thermos air dry once it’s been washed clean. Do not place the lid on it while it’s air drying.
3. If you’re using a stainless-steel thermos make sure your method of cleaning doesn’t damage it.
4. When not in use for a long time, store the thermos with paper towels inside it. This will help to absorb any odors in the thermos.

Final Thoughts

A coffee thermos is one of man’s greatest inventions! Keeping coffee hot is something many battle with but you don’t want to battle with keeping the thermos clean too. You want to leave the home for the day knowing you can pack your favorite coffee brew without worrying about making it somewhere else. But if you don’t take good care of your thermos you’ll soon be put off by bad or stale odors. By using the tips mentioned here you won’t need to worry about bad odors ruining your next cup of coffee.