Insulated Travel Mugs
Keep your drinks hot or cold for hours. Sealed for the journey. Built to be enjoyed.
How to choose an insulated travel mug
The six things that matter most.
Material
Look for food grade stainless steel, such as grade 304 (18/8 or 18/10), especially for the inner wall. Plastic, including eco-polymers, is lighter and cheaper but cannot hold temperature well. It also has a short lifespan, stains easily and holds on to odours. Glass is neutral to drink from but heavy and fragile.
Insulation type
Double wall vacuum insulation is the only build that holds heat for hours. If the outside feels warm, heat is escaping from your drink. Double wall glass usually has an air gap instead of a vacuum, so it holds heat for much less time.
Heat retention figures
Brands measure differently and few say how. Look for a figure with a stated method behind it, because the words "hot" and "cold" are subjective.
Lid type
A sealed lid can go in a bag on its side. A splash resistant lid cannot. The two terms get used interchangeably, so check which one you are actually getting.
Interior surface
Most travel mugs leave bare stainless steel inside. Ours is lined with Sol-gel, a ceramic like coating that is smooth and very stain resistant. Worth considering if taste matters to you, especially for coffee and tea, or if you switch between drinks.
Size and fit
Check that the base is wide enough to stay stable but narrow enough for your smallest cup holder. If you want it under a home coffee machine, check the height without the lid. You can also brew into a jug and pour it in afterwards.
What our insulated travel mugs are made from
The shell of our bru Travel is 18/10 stainless steel with a sol-gel ceramic lining and PP matt powder coated finish, it should be washed by hand to preserve the life of the coatings. The lid is solid PP plastic with silicone seals and is top rack dishwasher safe at low temperature. Every mug carries a two year warranty. There is also a silicone base place on the bottom to stop the bottom from slipping or getting scratched on solid surfaces. Replacement lids and seals are sold separately, because the lid is the part that wears and it should not mean replacing the whole mug. Do not microwave it.
How long an insulated travel mug keeps coffee hot and cold
Heat retention figures vary widely across the category, so it is worth knowing how ours is measured. Our bru Travel mug holds heat for up to 8 hours and cold for up to 12h. That is measured from boiling, with the mug filled to the line and the lid closed. Rinse it through with boiling water first, and fill it to the line rather than leaving an air gap. With tea, if you do both and you will get the full eight hours every time. Of course, if you like drinking nice coffee, you're not pouring it at 100C! You'll generally be pouring it in at about 85C and in that case, you'll get up to .....hours. For cold drinks, don't rinse with hot water but do place some ice cubes in the bottom. Also, bear in mind that the more liquid volume, the longer the heat/cold retention so the figures which are based on our most popular 16oz size, will be somewhat less for the smaller sized mugs.
Hot
Hot drinks stayed hot for 8 hours when poured at 97C.
This is water just off the boil, as if making a tea or Aeropress, with the lid kept off for a minute to reduce steam pressure.
Cup was rinsed with hot water prior to use and lid was not opened more than three times. Ambient air temperature was 21C.
Hot & Milky
Stayed hot for 4 hours when poured at 70C.
This is a lower starting temperature as milk should not be heated to more than 70C when adding to hot drinks as it makes it taste bitter.
Cup was rinsed with hot water prior to use and lid was not opened more than three times. Ambient air temperature was 21C.
cold
Chilled drinks stayed cold for 4 hours.
Fridge chilled water at 1.5C was added without ice, as if pouring a cold brew, for example.
Cup was rinsed with cold water prior to use and lid was not opened more than three times. Ambient air temperature was 21C.
Ice cold
Iced drinks stayed ice cold for 24h.
Cup was filled to the max line with ice, as if making iced latte and fridge chilled water was added.
Cup was rinsed with cold water prior to use and lid was not opened more than three times. Ambient air temperature was 21C.
X-RAY shot of a vacuum travel mug
What is inside an insulated travel mug
An insulated travel mug is two steel walls with a vacuum between them. The vacuum is the part doing the work. Heat needs something to travel through, and a vacuum gives it nothing, so your drink stays hot and the outside stays cool enough to hold. Cold drinks work the same way in reverse. The x-ray also shows the inside surface, and this is where mugs differ from each other more than the marketing suggests. The bru mug is ceramic lined and has a non-slip bottom which you can see on the x-ray shot.
The trade-off we made
We could have held heat for longer. The moulded indentation around the middle of the mug costs us a small amount of retention, because any change to the wall profile does. We kept it anyway. It makes the mug easier to grip with one hand, it stops it rolling on a desk, and it is the reason people take it out of the bag rather than leave it there. A travel mug only works if you carry it, and you carry the one you like the look of.
Sealed shut. Not just splash resistant
There is a difference between a lid that resists a knock and a lid that seals, and the two get used interchangeably across the category. A splash resistant lid keeps your drink in while the mug stays upright and without too much shaking. A sealed lid lets you put the mug on its side in a bag next to a laptop, if you dare! It lets you run for the bus holding the full mug in your hand and it even lets you put it into your pram cup holder without getting hot drink stains all over you and the pram as you traverse uneven pavements.
The bru lid seals shut. Firstly close the lid fully and evenly until you feel the bottom of the lid and the rim of the cup bite the silicone gasket which compresses as you twist. Press the lid cap into the shut position (watch the cap pop up into it's higher position). If you've been drinking from the lid, take a final sip after shutting the cap to get rid of any lingering drops of liquid inside the lid. Do these three things and you should avoid any accidents.
What you can put in an insulated travel mug
Our bru Travel ceramic lining is neutral, so nothing you put in it carries over to the next drink. Tea today does not taste of yesterday's coffee. Matcha does not pick up a metallic tang. Turmeric latte rinses out rather than clinging on. Hot drinks including americanos and herbal teas stay hot for up to 8 hours, which gives you plenty of time to finish 16oz of drink. Please leave the lid off for at least a minute to let hot steam evaporate so you don't accidentally create a pocket of steam pressure. Ice cold drinks hold for 24 hours, which covers a full day of iced coffee or water. The one thing to avoid is anything fizzy. Carbonated drinks build up pressure inside a sealed vessel and that is a safety issue in any sealed container, not just ours.
What size insulated travel mug do you need?
8oz / 230ml
A flat white or a single cortado. Finishes with the walk to the station.
12oz / 340ml
The most popular size. A standard takeaway coffee, and it fits a car cup holder.
16oz / 455ml
For the drive, or for a mug that lasts into the first hour at the desk.
Travel mug questions
What is an insulated travel mug?
A double walled steel vessel with a vacuum between the walls, designed to be drunk from directly and carried. It differs from a flask, which holds several servings and pours into a separate cup.
How long does it keep coffee hot?
Eight hours hot, twelve hours cold, measured from boiling with the mug filled and the lid closed. Fill it to the line rather than leaving an air gap, and rinse it with boiling water first. Both make a noticeable difference.
Is it leakproof?
The lid seals when fully closed, so it can go in a bag on its side. Check it is closed properly rather than resting in place.
Is it dishwasher safe?
The lid is, on the top rack. Hand wash the cup.
Is it microwave safe?
No. Steel and microwaves do not mix.
What size should I get?
8oz for a single espresso based drink, 12oz for a standard coffee, 16oz for a longer journey.
Does it fit a car cup holder?
yes, all 3 sizes will fit a car cup holder, the base diameter is 6.5cm on all 3 sizes.
Can I use it for tea?
Yes, and for matcha, hot chocolate and cold drinks. Avoid anything carbonated.
Will a coffee shop fill it?
Most will fill a clean reusable mug, and many take something off the price for it.
What if the lid wears out?
Replacement lids and seals are sold separately we also offer free seal replacements just drop us an email
What is the warranty?
Two years.
More from bru
- Looking for the ceramic travel mug itself? Start on our homepage.
- Ready to buy? Go straight to the bru Ceramic Travel Mug.
- Lid worn out? We sell replacement lids
- Need help with cleaning or the lid? See our video guides and instructions.
Built to be carried
Hot for 8 hours. Sealed for the bag. Two year warranty.