Thermos bottle: removing odours with household remedies

You unscrew the bottle and are greeted by the coffee from the day before yesterday? If you want to remove odours from your thermos bottle, you usually don't need any special cleaners. With warm water, a little patience and tried-and-tested household remedies such as baking soda or diluted vinegar, you can get most smells out again. This guide is about one thing only: getting musty, sour or coffee-scented bottles back to neutral – and making sure it doesn't happen again.

Contents10

1. Where the smell in your thermos bottle comes from
2. First aid: the quick basic clean
3. Thermos bottle: removing odours with household remedies
4. Which household remedy for which smell?
5. What you should avoid
6. When the smell just won't go away
7. How to keep the bottle permanently odour-free
8. Our bottles and how to care for them
9. Conclusion
10. Frequently asked questions

Where the smell in your thermos bottle comes from

Stainless steel itself hardly absorbs anything. According to the product description, both of our IZY bottles are made of rust-free stainless steel and are taste-neutral. Even so, any bottle can start to smell unpleasant after a while. The reason is almost never the metal, but what settles on it or is left standing inside.

• Coffee and black tea: They contain oils and tannins that form a thin, brownish film. This film holds on to the aroma – even if you only fill in water the next day.
• Milk, cocoa, smoothies: Protein and fat turn sour quickly when leftovers stand overnight.
• Residual moisture: If the bottle is closed while wet, a warm, damp climate develops inside. That quickly smells musty.
• The closure: The thread and the seal area are the typical places where residues collect. Often it is not the bottle that smells, but the lid.

So start with a sniff test: smell the open neck of the bottle and the closure separately. That way you know where to start.

First aid: the quick basic clean

Before you reach for household remedies, a thorough wash is worthwhile. For light odours, that is often enough.

1. Fill the bottle about one third with warm water and a drop of mild washing-up liquid.
2. Use a bottle brush to scrub the bottom, the walls and especially the neck.
3. Clean the closure separately with warm water and washing-up liquid, and go over the thread with a small brush or an old toothbrush.
4. Rinse thoroughly with clear water.
5. Let the bottle and lid dry separately and open.

This is exactly what the manufacturer of our IZY bottles recommends: by hand with warm water and a little mild washing-up liquid, not in the dishwasher. If a smell remains afterwards, it's time for household remedies.

Thermos bottle: removing odours with household remedies

The following remedies have long proven themselves in the household. They are inexpensive, usually already at hand and unproblematic for stainless steel in the usual dosage. Important: only ever use one remedy at a time and leave the bottle open while it soaks.

Baking soda or baking powder

Baking soda is the classic against coffee aromas. Put about one teaspoon into the bottle, fill it up with warm (not boiling) water and leave the solution to stand for several hours or overnight. Then brush out and rinse thoroughly. Baking powder works in a similar way, but is a little weaker.

Diluted vinegar

For sour or musty notes, a mixture of about one part vinegar to three or four parts warm water helps. Leave it for one to two hours, not for days. Then rinse several times with clear water so that no vinegar aroma remains. Always dilute vinegar essence heavily.

Lemon juice or citric acid

For a fresh note, use the juice of half a lemon or a little citric acid in lukewarm water. It's best not to use citric acid with very hot water – lukewarm is the usual advice. Here too: pour out after one to two hours and rinse well.

Rice as a scrubbing aid

For a stubborn coffee film, a tablespoon of uncooked rice with a little warm water and washing-up liquid helps. Shake briefly with the lid on, then open and rinse. The rice gently rubs off the residue without scratching the stainless steel.

Which household remedy for which smell?

Smell	Typical cause	Proven remedy	Soaking time
Coffee, roasted aroma	Coffee oil film on the walls	Baking soda, then rice to scrub	overnight
Black tea, bitter	Tannin residue	Baking soda or citric acid	2–8 hours
Sour	Leftover milk or juice	Washing-up liquid, then diluted vinegar	1–2 hours
Musty, “cellar”	Stored closed while damp	Diluted vinegar, then a long time drying open	1–2 hours
Only on the lid	Residue in the thread	Brush, soak in baking soda solution	1–2 hours

What you should avoid

Some tips from the internet are well meant, but harm the bottle or are simply unnecessary.

• Baking soda and vinegar at the same time: The mixture foams heavily and forms gas. Pressure builds up in a closed bottle. If at all, use them only open and one after the other – better to keep them separate altogether.
• Chlorine cleaners and bleach: They are not intended for drinking vessels and can attack stainless steel.
• Steel wool and scouring cream: They scratch the inner wall. Residues later settle even more easily in fine scratches.
• Boiling water with cleaners: Never close and shake hot solutions with tablets or baking soda.
• The dishwasher as a shortcut: For our IZY bottles, the manufacturer expressly advises against it in order to protect the surface and the insulation.

When the smell just won't go away

Sometimes even a second round of baking soda doesn't help. Then it's worth taking a closer look.

If it is mainly the closure that smells, the residue is probably sitting in hard-to-reach gaps. Check the instructions for your bottle to see whether parts can be removed for cleaning – we don't claim this for any particular bottle, because it differs from model to model. How to go about it is a topic of its own; our article on the water bottle in summer briefly covers general care.

If you see dark spots, a greasy film or fluffy patches, it is probably no longer just a matter of smell. In that case, you should not use the bottle again until it has been thoroughly cleaned. With visible growth, buying a new one is often the safer choice.

And sometimes the smell is a sign of habit: if you always fill in coffee, you will hardly ever get rid of a hint of it completely. That's why many people use one bottle for coffee and a second one for water or tea.

How to keep the bottle permanently odour-free

The easiest thing is not to let odours develop in the first place. These habits have proven themselves:

1. Rinse right after emptying. Even clear, warm water prevents coffee or milk from drying on.
2. Rinse briefly in the evening, not just at the weekend. A drop of washing-up liquid and the brush are enough.
3. Let it dry open. Let the bottle drain upside down, then leave it standing with the neck open. Put the lid next to it.
4. Don't store it closed. Anyone who keeps the bottle screwed shut in the cupboard for weeks will almost always find a musty hint when they open it.
5. Don't leave drinks standing for days. What you fill in today, you drink today.
6. Baking soda once a week. If you drink coffee every day, a short baking soda round at the weekend is a good routine.

Our bottles and how to care for them

In our shop you will find two IZY thermos bottles of 500 ml each. According to the manufacturer, both are double-walled, made of rust-free stainless steel, BPA-free and taste-neutral. They keep drinks hot for up to 12 hours and cold for up to 24 hours and have a leak-proof screw cap.

• The IZY Bottles Van Gogh Flowers thermos bottle with a colourful floral design inspired by Vincent van Gogh.
• The IZY x Pip Studio “La Dolce Vita” thermos bottle with a playful Pip Studio pattern, delivered in a round gift tin.

The same care applies to both: hand wash with warm water and mild washing-up liquid, no dishwasher. With the household remedies above, you stay within exactly this framework. You can find all models in our IZY collection.

Related reading: Cleaning the lid and seal: how to get the closure clean · Drying and storing your water bottle: how to keep it fresh · Coffee in a thermos bottle: how it stays hot and aromatic

Conclusion

An unpleasant smell in your thermos bottle is no reason to throw it away. Usually a film of coffee, tea or milk is behind it, or the bottle was closed while damp. Wash thoroughly by hand, clean the closure separately, then let baking soda or diluted vinegar work – that solves the vast majority of cases. Afterwards let it dry open and don't store it closed, and the bottle will stay neutral. Only when there are visible deposits or stains that cannot be removed is it time for a new one.

Frequently asked questions

How do I get the coffee smell out of my thermos bottle?

Best with a teaspoon of baking soda in warm water overnight. Then brush out, scrub with a little rice if needed and rinse thoroughly.

Can I use vinegar and baking soda together?

We advise against it. The mixture foams and forms gas, and pressure builds up in a closed bottle. It's better to use one of the two and rinse in between.

How long can vinegar stay in the bottle?

Diluted vinegar needs one to two hours. Leaving it longer hardly helps and can leave a vinegar taste. Then rinse several times with clear water.

Does the dishwasher help against odours?

Not for our IZY bottles: the manufacturer recommends hand washing only, so that the surface and the insulation stay protected. For other bottles, check the manufacturer's instructions.

Why does my bottle smell musty even though it was clean?

Usually it was closed while still damp. After washing, let the bottle and lid dry completely, separately and open, and store them without the closure screwed on.

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Personally written by Martin – founder of BeachAndSteam and sauna operator at Lake Kulkwitz for more than 18 years.