Insulated Food Jars for Kids
Warm lunches, sorted.
Leftovers, pasta, soup, yoghurt or fruit, kept hot or cold until the lunch bell. From our bestselling jars that fit inside the bbox to a bigger 400ml jar for hungry kids, here's how to pick the right one and get the most out of it.
Which food jar is right for your kid?
It mostly comes down to appetite and whether it needs to fit inside the lunch box. Our two bestsellers, the MontiiCo Mini and the Oasis 230ml, both slot into the bbox original. The 400ml travels in the lunch bag.
Mini 200ml
Kindy, prep and snack-sized serves- Fits the bbox original
- Stays warm for up to 5 hours
- Screw lid with easy-grip silicone band
- Dishwasher safe, every part
Colours: navy, lilac
230ml
Kindy and primary, a little more room- Fits the bbox original and MontiiCo Feast
- Hot up to 4 hours, cold up to 6
- Flip-to-unlock quick-release lid
- Hand wash recommended
Colours: blush, bubblegum pink, hazy blue, mermaid purple, peacock blue
Regular 400ml
Bigger primary kids and tweens- Stays warm for up to 8 hours
- Screw lid with easy-grip silicone band
- Dishwasher safe, every part
- Goes in the lunch bag, not the lunch box
Colour: splash
The b.box food jar is on its way.
Made by b.box to sit right in the bbox original lunch box. Join the Sinchies family and you'll be the first to know when it lands, plus 10% off your first order.
Compare our food jars
| Jar | Capacity | Best for | Fits bbox original | Keeps food warm | Lid | Cleaning | Price |
|---|---|---|---|---|---|---|---|
| MontiiCo Mini | 200ml | Kindy, prep, snacks | Yes | Up to 5 hours | Screw lid, grip band | Dishwasher safe | $29.95 |
| Oasis 230ml | 230ml | Kindy and primary | Yes | Up to 4 hours (cold up to 6) | Flip quick-release | Hand wash | $29.95 |
| MontiiCo Regular | 400ml | Bigger kids, tweens | No, lunch bag | Up to 8 hours | Screw lid, grip band | Dishwasher safe | $34.95 |
| b.box food jar | Coming soon. Made to fit the bbox original. | ||||||
Times are the maker's ratings and assume a preheated, full jar. Swipe the table sideways on your phone to see every column.
What to put in your food jar
The easiest win: cook a little extra at dinner and pack the leftovers. Thicker foods like pasta sauce, soups and curries hold their heat better than loose foods like noodles.
Warm and filling
- Spaghetti bolognese or mac and cheese
- Fried rice
- Butter chicken or curry and rice
- Meatballs in sauce
- Soup on cooler days
- Noodles
- Nuggets (with a paper towel underneath)
Fresh and chilled
- Yoghurt with granola on the side
- Overnight oats
- Fruit salad
- Smoothie bowls
- Pasta salad
- Chopped veg and dip
How much to pack
- 200–230ml: a kindy-sized serve of pasta, yoghurt or fruit, alongside the rest of the lunch box
- 400ml: a proper main for bigger kids, tweens and teens
More ideas: 5 hot school lunches and 5 easy winter lunches.
How to prepare your food jar
An insulated jar doesn't heat food. It holds in the heat you give it, so the prep in the morning makes all the difference.
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Preheat the jar
Fill it with boiling water for 5–10 minutes. Rest the lid on top rather than sealing it, as steam builds pressure inside. Tip the water out just before filling.
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Heat food hotter than usual
The hotter it goes in, the better. Stir microwaved food well, as it's often steaming on the outside and cold in the middle.
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Fill it to the top
A full jar has less air inside, and less air means better heat retention. Pick the jar size that matches the serve.
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Seal it and leave it
Every peek lets heat out. Ask little ones not to open it until lunch, even to show their friends at recess.
Pre-chill the jar with ice and water for 10 minutes, or pop it in the fridge, before filling with yoghurt, fruit or overnight oats.
Pack a hot jar separate to the ice pack, or use a lunch bag without one, so each does its own job.
Food not hot enough? Start here.
Most temperature issues come down to how the jar was prepared, not a fault with the jar. Run through these first.
A cold jar steals heat
A jar that hasn't been preheated draws heat out of your food the moment it goes in. Fix: boiling water for 5–10 minutes, every time.
Microwaves heat unevenly
Food can be steaming on the outside and cold in the middle. Fix: stir, check the middle and heat it hotter than you'd eat it.
Air cools food fast
A mini quiche or two nuggets in a big jar won't stay hot. Fix: fill it right up, or choose a smaller jar for smaller serves.
Every peek lets heat out
Opening it at recess swaps the hot air for cold. Fix: keep it sealed until lunch.
Check the rated time
Filled at 7am with lunch at 1pm is 6 hours, past the Oasis 230ml's 4-hour rating. Fix: fill as late as you can, or choose a jar rated for longer.
Warm isn't always piping hot
What feels hot to one person can feel lukewarm to another. A jar keeps food warm and safe to eat, not straight-off-the-stove hot.
Trap the steam
Pop a piece of paper towel in the bottom of the jar to soak up moisture and keep crispy foods crunchier.
That's a vacuum fault
If you can hear water moving between the two walls, the vacuum seal has failed and we'll cover it under warranty. Dents aren't covered, as a drop is the most likely cause of a seam failing.
Why is the outside cool when the food is hot? The double-wall vacuum stops heat moving through the jar, so the outside stays cool or room temperature while the food inside stays hot. That's also why the rest of the lunch box stays cool next to it.
Food jar FAQs
Can't see your question? Send us a message and we'll get back to you.
Which food jars fit in the bbox lunch box?
The MontiiCo Mini 200ml and the Oasis 230ml both fit in the bbox original lunch box. The Oasis 230ml also fits the MontiiCo Feast. The 400ml is too tall for the lunch box and travels in the lunch bag instead. A b.box food jar designed for the bbox original is coming soon.
How long do they keep food hot or cold?
- MontiiCo Mini 200ml: warm for up to 5 hours
- Oasis 230ml: hot for up to 4 hours, cold for up to 6 hours
- MontiiCo Regular 400ml: warm for up to 8 hours
All ratings assume a preheated, full jar that stays closed until lunch.
Are food jars microwave safe?
No. Insulated jars are double-wall stainless steel and must never go in the microwave. Heat the food in a bowl, then transfer it to the preheated jar.
Are they dishwasher safe?
The MontiiCo jars are dishwasher safe, base, lid and all. For Oasis jars, hand washing is recommended to protect the finish and thermal performance. Wash promptly to avoid odours. If food has been left for a few days, soak in hot water for 5 minutes before washing.
How do I clean the lid?
Oasis lids twist off so you can hand wash them, then put them back together once dry. MontiiCo lids have a removable silicone seal inside, so you can take it out and clean underneath.
Can my child open it on their own?
The Oasis jars have a quick-release lid that flips to unlock, designed for young kids to open independently. MontiiCo jars have a screw lid with an easy-grip silicone band. If your little one struggles with twisting, the Oasis 230ml is the easiest to open.
Which size should I buy?
For kindy and prep, or as one part of a bigger lunch, go 200ml or 230ml. For bigger appetites, tweens and teens, the 400ml. Our food jar buying guide has more detail.
Do nuggets go soggy?
Put a piece of paper towel in the bottom of the jar to absorb steam and keep them crunchier.
Will a hot jar make the rest of the lunch box warm?
No. The vacuum-insulated, double-walled design keeps the heat inside, so the outside of the jar stays cool or room temperature.
What are the dimensions?
- MontiiCo Mini 200ml: approx. 9.4cm x 6.5cm
- Oasis 230ml: approx. 11.5cm wide x 6cm tall
- MontiiCo Regular 400ml: approx. 9.4cm x 10.5cm
What's covered by the warranty?
Our jars carry a 6-month manufacturer's warranty. Genuine faults are rare. The most common is a failed vacuum seal, which you'll notice as water swishing between the two walls, and that is covered. Dents aren't covered, as a drop is the most likely reason a seam fails.
What are they made from?
All our jars are double-wall, vacuum-insulated 18/8 stainless steel, and BPA and lead free. Oasis jars have a durable powder-coated finish.
More food jar reading
Swap the soggy sandwich for something warm.
Pick a jar, pack last night's leftovers, and lunch is sorted.
