This post explains the differences in how long food stays hot inside a thermos between the most popular brands, keeping the food hot, and selecting the right container for your needs.
While manufacturers advertise how long their brand keeps food hot, some things can help you get the most out of your container so the thermos lunch stays warm until lunchtime.
How long does a thermos keep food hot
The amount of time you need to keep food hot will depend on when you pack the lunch and heat the food and when it will be consumed. On average, most of us need to keep food hot between 6 and 7 hours.
Depending on your brand of thermos lunch container, food will stay hot for between 5 and 12 hours, so the one you purchase matters.
Check out this comparison chart by brand and price:
| Brand | Hours Hot | Price (avg) |
|---|---|---|
| Thermos Foogo | up to 5 | $15 |
| Thermos Funtainer | up to 5 | $15 |
| Bentgo | up to 6 | $29 |
| Stanley Classic | up to 12 | $22 |
| Stanley Heritage | up to 8 | $24 |
| Mira | up to 5 | $16 |
| Omiebox | up to 4 | $45 |
| Lunchbots Wide | up to 5 | $34 |
| Lunchbots Classic | up to 6 | $20 |
Learn more about the features of each of those insulated containers here.
How to keep food hot in a thermos for Lunch
The best way to keep the food hot as long as possible inside the thermos container is to heat it up properly before transferring it into the thermos. This means the food should be heated up piping hot, meaning too hot even to taste!
You can also preheat the thermos by filling it with boiling water and letting the heat warm up the metal sides and the air space between the double insulated walls.
Is it safe to keep food warm in a thermos?
Food that was cooked and stored properly makes a terrific thermos lunch. The thermos’s job is to keep the food at a safe-to-eat temperature for hours after being heated up properly and packed inside.
The time between when you warm up the food to when it will be enjoyed determines which thermos container is best for you! For this reason, most brands list an approximate time of how long it will retain the food’s temperature inside the insulated walls of the container.
How to Pack Hot and Cold Lunch Together
Packing hot and cold lunch foods inside the same lunch bag is possible by placing the hot food inside a thermos and the cold items, such as fruits and veggies, separately.
If you need to add an ice pack to keep other food items chilled, place it away from the thermos container that’s keeping the warm foods and near the cold food items.
Here is a quick video showing you how to pack hot and cold lunches the right way:
Best Hot Food Thermoses
Three things make up the best thermos container for your lunches; how much food it can hold, how long it will keep the food hot inside, and the features that make it age-appropriate for your child; meaning ease of opening and getting the food out.
Tip: if you’re packing food in a thermos for the first time, let your child try it at home first so they can open and close the container independently.
Here are 3 great performing thermoses:
You can't go wrong with any of the options above for packing lunches. A thermos is a terrific vessel for repurposing leftovers and sending hot and cold foods for lunch! A great place to start is with these delicious thermos soup recipes.
Sunetra says
Should I still use cold packs inside the lunch box while packing a hot lunch in a thermos?
MOMables says
Yes. a thermos keeps the temperature hot inside. the icepacks are for the rest of the food (when needed)
Erica munden says
Hi
I would like to know if any one has any suggestions on a food box or something to keep food hot, I,m going to do a food service driving round before I buy a jiffy van,
Ericaxx
MOMables says
I’m sorry, I don’t know. perhaps you can go on amazon and look for those big delivery bags that the pizza people use?
Kelly says
The catering company my daughter worked for used regular coolers like igloo. They heated the food in foil serving dishes and stacked them in the coolers.
Jorge says
Hello,
Does anybody has any experience using Mr. Or Ms Bento container kits?
MOMables says
No, I’m sorry. I prefer thermos containers or those made of stainless steel specifically for hot items
Ann Marie says
This may be a silly question, but his do you heat up the thermos? Is it microwave safe? The one I own has a metal interior.
Thanks
Ann Marie says
I did see your post on how to heat up the thermos, thanks!!
Nikki says
I am looking for a good container for my husband that will hold plenty of food for him and keep it warm for quite a while. I was checking out the Stanley you shared about above and while reading reviews some people was saying that this was great at first and then lost its seal and wasn’t keeping the food hot for long, after only a month or so. I was wondering if you have experienced this at all? Thanks soo much, just found your site today (from 100 days of real food) and already love it!
http://www.amazon.com/Stanley-17oz-Classic-Vacuum-Black/dp/B0019D7AGE/ref=lh_ni_t?ie=UTF8&psc=1&smid=ATVPDKIKX0DER
MOMables says
Hi Nikki! Thanks for visiting us! I love that Stanley thermos. That’s the one my husband takes to work. The seal might of come off for other people if they wash and dry the lid in the dishwasher. I only wash the bottom of it, the top by hand. The “seal” is a rubber gasket/band and can come loose with high temperatures. I’ve had mine for over a year with 2-3x week use and no issues. :)
brittany says
Why no onions??
MOMables says
they tend to stink the lunchbox, often make other foods soggy..etc.
Amie says
You have mentioned heating up the thermos but most are stainless steel so can’t go in the microwave. How do you recommend heating them up properly?
MOMables says
Amie, check this post.
Kimberly says
Thank you for this informative post! I love your site, and your newsletters. It is nice to follow you on Pinterest, as well, to see specific articles like this one on mornings when it seems like I need the advice the most! Your efforts for this experiment will help many, many Moms out there to pack great hot lunches! I do have one question – when I pack a Thermos with hot lunch for my kids I often don’t know what else to include with the entree. I am so used to packing items with a cold pack that I don’t know what accoutrements I can send with a hot Thermos full of, for example, ravioli with sauce. What items do you suggest?
MOMables says
Kimberly, pack anything else you would normally send. the thermos containers don’t absorb heat or cold from the outside. I send fruit, veggies and dip, some of the bars in our recipe section… a thermos is just a container… send the same items you would normally pack in another container.
Kimberly says
Thanks for your response! Do you still use a cold pack to keep the other foods chilled?
MaryB says
I use a Packit for my kid’s lunches and we put the Thermos inside with the rest of the food. The food inside the Thermos stays hot just fine. We use the Funtainers.
Rashelle says
So thorough, thank you for the great advice.
Debbie W says
Excellent advice. I have the 10 oz. Thermos brand stainless containers plus another bigger stainless container that I don’t remember the name of. I always preheated the container by pouring boiling water in it. After dumping the hot water, I then added the hot soup. My daughter had no problems at all when she was young with this. Especially since she’s my soup kid. From when she was tiny to today, at 21, she will still eat soup before most other things.