How to Choose the Best Thermos or Insulated Food Jar for You

January 15, 2023 Biome

There is nothing like a hot lunch during winter, and a thermos or insulated food jar makes it easy for you to take your own zero waste hot lunch, saving you money and waste on expensive takeaway. But with so many insulated food jars available, how do you know what's right for you?

How to find the best thermos and insulated food jar for you | Biome Eco Stores

How does a thermos work?

A thermos or insulated food jar is a container or bottle with a double-walled container inside of it. The air between the two walls is removed when the product is manufactured, creating a vacuum. This allows it to keep food hot by not allowing heat to escape. A thermos keeps food cold in the same way. Heat from the outside that might otherwise transfer to the cold contents of the insulated food jar, is prevented from reaching it because of the vacuum between the thermos wall.

Which foods can go in an insulated food jar?

Our insulated food jars are ideal for both hot and cold food. We have large and small thermos depending on the quantity of food to be added. Foods like soup, stew, curry, pasta and stir-fry will keep warm for hours in an insulated food jar. Some customers even like to pack toasted sandwiches or last night's pizza! Meanwhile, yoghurt, muesli and fruit salad are great cool food options.

Our Bentgo Insulated Food Containers can hold up to 560mL of food. This is plenty of room for a hearty serving of soup, a full breakfast of granola and yoghurt, or just about any food you'd like for lunch! They have two layers of stainless steel surrounding a triple-layer insulation method, featuring a layer of copper as well as the traditional vacuum layer. Best of all, their wide mouth design means it's easy to eat straight from the container, eliminating the need to dirty two plates and use more water washing up.

Dishwasher safe, almost completely recyclable, and with the ability to keep your food hot or could for hours and hours, these containers are sure to take your lunch game to the next level!

Which insulated food jars are best for kids?

This really depends on how much your child eats and how easily they find opening the insulated food jar lid. We recommend doing a few test runs at home before sending you kids to school with one, just to make sure they are comfortable using it. Our insulated food jars range in size from 290ml capacity to 750ml. Some are short and wide in design, while others are tall and skinny. Here are our insulated food jars that are best suited to kids and their small hands:

We also have some larger insulated food jars that are more suited to adults or older teens, including the Goodbyn insulated food jars, BBBYO foodie and Thermos King.

See our full range of kids thermos and other insulated food jars here >

Benefits of stainless steel inside the lid

You may notice that some insulated food containers that we sell have only stainless steel on the inside of the lid, while some of our other other insulated food jar lids are plastic. Our plastic insulated food jar lids are still safe, and free from toxins, phthalates, BPA and PVC, and really great options. However there are two benefits of having stainless steel on the inside of the lid:

No plastic touches your food; and
The colour and smell of the food isn't absorbed by the plastic on the inside of the lid, making it easier to keep clean.

How do I get the maximum heat retention from my insulated food jar?

In the table below we have listed the maximum amount of time you can expect your food to stay warm or cool for. To keep your food warm or cool for as long as possible, we recommend pre-heating or pre-cooling, as follows. Preheat your insulated food jar by filling it with boiling water. Leave for five minutes before pouring out and adding your hot food. Similarly, if you are adding cold food, like yoghurt or fruit salad, pop your insulated food jar in the freezer for 15 minutes with the lid off. Remove from freezer and add your cold food. Keep in mind that the the more air or free space you leave in your insulated food jar, the quicker the contents will cool down, so it's best to use a jar based on how much food you will be filling it with.

Thermos comparison

	Capacity	Time Hot	Time Cold	SS Lid?	Kids?
Bentgo Stainless Insulated Food Container	560ml	'For hours'	'For hours'	No	8+
Thermos Foogo Food Jars	290ml	5 hours	7 hours	No	8+
Thermos FUNtainer Food Jar	290ml	5 hours	7 hours	No	8+
Thermos insulated food jar with folding spoon	470ml	7 hours	9 hours	No	No
Frank Green Insulated Ceramic Food Container	295ml	Not stated	Not stated	Yes	8+
Frank Green Insulated Ceramic Food Container	475ml	Not stated	Not stated	Yes	8+
Klean Kanteen TKCanister vacuum insulated food jar	237ml	5 hours	20 hours (cool)	No	8+
Klean Kanteen TKCanister vacuum insulated food jar	946ml	11 hours	45 hours	No	8+
BBBYO Foodie + Cover	750ml	12 hours	24 hours	No	No
Yumbox Zuppa insulated food jar with spoon	415ml	6-8 hours	12 hours	Yes	8+