I'm Biggie: avid cook, speedy lunch packer, mom in San Francisco, & former expat fluent in Japanese. 
Thermal lunch jar shootout
If you’d like to have warm food at lunch but don’t have access to a microwave oven where you eat, odds are good that you’ve looked into different thermal food jars and thermal lunch jars. Whereas a thermal food jar is typically a small widemouth thermos that you put food directly into, a thermal lunch jar is a vacuum insulated jar that holds a number of smaller microwaveable bowls stacked neatly inside. Preheat (or prechill) by filling the outer jar with hot or cold water for 1-2 minutes, empty and dry the outer jar, pack up your lidded bowls inside, and you’ve got a portable meal that’s not just room temperature food.
Two good-quality large lunch jars are the US$50 Zojirushi Mr. Bento
When I was first in the market for a thermal lunch jar a couple of years ago, I went to a store with a variety that I could take out of the box and compare in person. I thought the cheaper Lunch Tote from Thermos Nissan was on par in quality to the more popular Mr. Bento, but was always curious about how the two would fare in a side-by-side comparison against a cheap no-name knockoff I found locally (at left). Zojirushi sent me a Mr. Bento for testing so that I could satisfy my curiosity; I’ll be giving this to a lucky reader in a giveaway now that I’m done (enter by October 5, 2008, see the separate post for details). (NOTE: Comments on this post are not eligible, only comments on the separate giveaway post are eligible to win.)
Summary
The Mr. Bento and Thermos Nissan were extremely close in performance and weight, with the Thermos Nissan having better overall heat/cold retention and the Mr. Bento having better separation between the upper and lower sections. The Mr. Bento’s separate bag is convenient for tucking in lunch extras like condiments and utensils, though. The cheap Chinese knockoff jar performed significantly worse in tests, but at US$10 the price was right for a small jar. The Thermos Nissan is usually priced at least US$10 cheaper than the US$50 Mr. Bento, so decide if the bag is worth a little extra money to you. (Read on for the full review and test results…)
Lunch Jar Pros
- Lunch jars effectively keep foods warm or cool for hours until you eat, and the separate bowls prevent flavors from mixing.
- The thermal lunch jars often feature a leakproof soup bowl: an excellent way to send liquid foods like soup, stew or curry.
Lunch Jar Cons
I don’t use our big thermal Thermos Nissan lunch jar that often because it packs way too much food for my preschooler according to the bento box size guidelines, but I did use it when packing lunches for my husband during his gluten-free period. He came back saying that it was too big even for him, so I started packing an afternoon snack in one bowl, or packing the containers less densely by including a small salad or a bun for a do-it-yourself sandwich lunch. I picked up a small no-name lunch jar to reduce portion sizes; Zojirushi also puts out a line of 2- and 3-bowl Ms. Bento thermal lunch jars- My husband’s main complaint with the lunch jars is that their weight (2 lbs 4.5 oz for the Nissan) and bulk made it impossible to fit into his messenger bag on the way to work. Because of their size, he often stashed the empty container in a drawer or under his desk after eating, and forgot to bring it home at night (out of sight, out of mind: see my post on six ways to make sure your lunch gear gets home).
Packing
If you have a microwave where you eat, you can pack a thermal lunch jar with all chilled food and microwave the individual bowls that you want warmed (minus the lids, which can warp). Like many plastics, the bowls can stain if packed with tomato- or turmeric-based foods. See my post on Caring for Your Bento Gear for ways to remove stains and odors from plastics, or my post on microwaving plastics for health concerns.- The large rice bowls tend not to be watertight, but you can use the “rice lid” packing method to pack a liquidy stew or curry in the bottom of the rice bowl, with a layer of rice or grains on top to keep the liquid from sloshing out. This is especially handy when using other food jars or the smaller Ms. Bento thermal food jar without a dedicated leakproof soup bowl.
- If you have a thermal lunch jar, don’t forget that you can always use the containers separately when packing a bento-style meal, as I did when I packed just the lunch jar bowls in a wine bag. The sealed soup bowl comes in especially handy when packing dipping sauces, and can be tossed around in a backpack without leaking.
Inspiration
Browse thousands of photos of meals packed in thermal lunch jars on the large and active Mr. Bento Porn group on Flickr. The group’s discussion board also has tips and information specific to thermal lunch jars, making it an excellent place to pose related questions.- There’s also a small Flickr group for vegetarians: the new Mr. Bento Vegetarian/Vegan Porn.
Giveaway
A lucky reader will win a free Zojirushi Mr. Bento thermal lunch jar; leave a comment at the separate giveaway post and I’ll choose one at random on Monday, October 6, 2008 using random.org. The Mr. Bento lunch jar will be the same one that I tested here by filling it with water (no food has been packed in it). Zojirushi sent me one to test out, but my Product Reviews policy prohibits me from keeping anything valued over US$40 so it’s time to pass it on. (Click on any photo for a larger view.)
Here are the Nissan Thermos vs. Mr. Bento, and the no-name knockoff vs. the Nissan Thermos lunch jars. The soup bowls nestle into the bottom, followed by the large main bowl (often used for rice or the meal’s carbohydrate), and the two side dish bowls. The Nissan Thermos and Mr. Bento’s rice bowls have insulated lids designed to keep the heat or cold in the bottom two bowls. The cheap knockoff does not have an insulated lid, and its heat retention reflects this (see the tests results in the table below).
The Nissan Thermos is the only one with a stainless steel exterior, making it quite modern and masculine. The Mr. Bento’s gray plastic exterior is unobjectionable and sturdy, though — much better than the chintzy plastic knockoff with an easily broken top handle.
Here are the two thermal jars side by side (Thermos Nissan on the left, Mr. Bento on the right). The Mr. Bento is slightly shorter and wider than the Thermos Nissan, with a secure clip-on top lid and a domed bottom. The Thermos Nissan’s top lid screws on securely, and is touted by the manufacturer as being sturdy enough to be used as an additional bowl when eating.
The Mr. Bento comes with its own black carrying bag with two outer pockets, side zipper, detachable carrying strap and drawstring tie around the top (napkin not included). The strap is long enough to wear messenger-style if you’re biking to school or work. The strap on the Thermos Nissan is shorter, and is suitable for shoulder wear only. My knockoff jar has an ugly plaid carrying bag that is too tight for adding utensils, and the strap length is not adjustable. I personally prefer the Mr. Bento bag as it’s convenient for tucking in extra utensils or condiments, and it protects the jar’s exterior finish. That said, my husband prefers the simplicity of the all-metal Thermos Nissan without the bag to mess with. Just our personal preferences.
Both the Nissan and Mr. Bento come with a utensil and carrying case. The Nissan Stainless has a spoon and full-length carrying case that can also hold a small pair of child-sized chopsticks (not included). The whole utensil case slides into a holder on the outside of the lunch jar. The Mr. Bento comes with a spork and a small hinged case that covers just the spork’s business end, keeping the weight down. If you want to pack a different utensil with the Mr. Bento, the spork cover might fit on other utensils or you can wrap a different utensil in a napkin and tuck it down into the Mr. Bento bag.
Here are the two soup containers, showing both top and bottom of the lids (Nissan on the left, Mr. Bento on the right). Both lids have removable rubber gaskets set into the bottom, and secure screw-on lids that keep liquids from leaking out of the container. The lids have different grip styles on top; I found both easy to grab when lifting a full container out of the bottom of the lunch jar.
The rice bowls are the largest containers in each set, and have insulated lids that are designed to keep the heat (or cold) in the bottom half of the thermal lunch jar. Design and quality are similar, although the insulation in the Mr. Bento lid performs slightly better than the Nissan (see the hot/cold retention test results in the table below). For food safety reasons, the manufacturers advise against packing hot and cold foods together at once in the same lunch jar. Instead, they recommend either chilled dishes in all four bowls, hot in the bottom and room temperature on top, or chilled in the bottom and room temperature on top. The rice bowl is NOT watertight at all, but you can use the “rice lid” packing method to expand your lunch options.
The two side dish bowls have similar plastic lids that effectively contain moisture but are not perfectly watertight. This makes them fine for moist foods but not suitable for soup. Quality of the Thermos Nissan and the Mr. Bento are pretty equivalent. The side dish bowl on my no-name knockoff does not have a securely sealing lid, and is more prone to spillage than the Thermos Nissan or the Mr. Bento. The manufacturers advise against putting hot food in the top two bowls in order to avoid warping the lids (the same reason you’ll want to avoid putting the lids in the microwave or hot dishwasher cycles).
| Zojirushi Mr. Bento SL-JAE14 |
Thermos Nissan JLN1200X | no-name Chinese knockoff | |
| Heat retention (see Note #1) |
small: 85.8° F medium: 88.5° F rice: 107° F soup: 110.5° F (average: 97.95° F) |
small: 89.1° F medium: 92.3° F rice: 108° F soup: 111.5° F (average: 100.2° F) |
side bowl: 85.8° F rice: 107° F (average: 90.3° F) |
| Cold retention (see Note #2) |
small: 69.1° F medium: 67.1° F rice: 61.3° F soup: 60.6° F (average: 64.5° F) |
small: 67.3° F medium: 65.5° F rice: 61.0° F soup: 59.7° F (average: 63.4° F) |
side bowl: 66.4° F rice: 64.8° F (average: 65.6° F) |
| Hot/cold retention (see Note #3) |
small: 75.9° F medium: 78.1° F rice: 99.7° F soup: 103.0° F (cold avg: 77° F, hot avg: 101.4° F) |
small: 77.0° F medium: 78.4° F rice: 98.1° F soup: 102.5° F (cold avg: 77.7° F, hot avg: 100.3° F ) |
side bowl: 78.3° F rice: 83.3° F |
| Capacity | Total: 1230ml (41.6oz) (from company) small: 200ml (6.8oz) medium: 300ml (10.1oz) rice: 450ml (15.2oz) soup: 280ml (9.5oz) |
Total: 1140ml (measured by me) small: 200ml medium: 280ml rice: 380ml soup: 280ml |
Total: 800ml (measured by me) side bowl: 350ml rice: 450ml |
| Dimensions | 8.5″ x 5.25″ (H x D) | 9.5″ x 4.75″ (H x D) | 7.25″ x 5″ (H x D) |
| Weight | Total: 2 lbs 6 oz Jar & bowls alone: 1 lb 14.9 oz |
Total: 2 lbs 4.5 oz Jar & bowls alone: 2 lbs 2.2 oz |
Total: 1 lb 11.6 oz Jar & bowls alone: 1 lb 8.7 oz |
| Utensils | spork & plastic half-cover | spoon & plastic full case | n/a |
| Watertight? | soup bowl: 100%, side bowls: mostly, rice bowl: no | soup bowl: 100%, side bowls: mostly, rice bowl: no | no |
| Microwave-safe? | Bowls only, not lids | Bowls only, not lids | Bowls and lids only |
| Dishwasher-safe? | Bowls only, not outer thermal jar | Bowls only, not outer thermal jar | Bowls & lids only, not outer thermal jar |
| Cost | List price US$65, street price US$51 and lower (Amazon) | US$38 and lower (Amazon) | About US$10 (local Asian discount store) |
Notes
- Heat retention: I preheated the thermal jar with boiling water, and filled the bowls with 128° F water. The lunch jars stood for 6 hours in a 75° F room.
- Cold retention: I prechilled the thermal jar with ice water, and filled the bowls with 56° F water. The lunch jars stood for 6 hours in a 70° F room.
- Mixed hot and cold retention: I left the thermal jar at room temperature, filled the bottom bowls with 128° F water, and filled the top bowls with 56° F water. The lunch jars stood for 6 hours in a 69° F room.
(Disclosure: The Amazon links are affiliate links that support Lunch in a Box at no additional cost when you use them to shop.)
FURTHER READING:
- All “thermal lunch jar” posts on Lunch in a Box
- Hot vs. cold lunch packing considerations
- Product Reviews on Lunch in a Box
- Bento FAQ and Top Speed Tips
September 22nd, 2008 | Categories: equipment, review, thermal lunch jar | 
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September 22nd, 2008 at 1:26 pm
First, thanks for sticking to your guns about your policy, second, thanks for offering this for a giveaway, third, what I would pack…
Anything and everything. My hubby is a cop and while they do have a lunchroom and a microwave they rarely get to sit down long enough to eat warmed up food.
I am new to bentos and while great for the kids and I, he always has cold food. With winter coming up I was wondering what to do for yet another cold year.
Usually he ends up with hot soup in a big thermos.
With a thermal bento jar I could pack leftovers for him already heated so he could just open and eat one container’s worth if needed in between calls.
Plain, simple, and easy is what we do so what would we pack? LEFTOVERS!
September 22nd, 2008 at 1:36 pm
I wonder how the Japanese version of the Mr Bento would compare. It only has 3 bowls, and hashi instead of a spoon. I don’t know if the manufacturing is different between the stuff marketed to the states and the products sold in Japan, but my Mr Bento and Ms Bento (both Japanese-style) both keep things mighty hot, even without preheating. Maybe Zojirushi would send you one of those to test? ^_^
September 22nd, 2008 at 2:19 pm
Thanks for the comparison…I was curious myself on how things handle and this proves that paying a little money is probably a good investment…
and I love thai curry and a side of rice so I can then mix it how I want…
mmmmmm
September 22nd, 2008 at 2:19 pm
OMG! Can I just tell you how much I LOVE your anal-retentive attention to this post!!! Numerous photographs with detailed explanations AND an entire chart of your results. You are my hero! Love, Love, LOVE IT!!!!
September 22nd, 2008 at 2:21 pm
Thanks for this review, this makes it so much easier to decide! And I totally forgot about The Ms. Bento.
Thanks for sharing the Mr. Bento Porn links, I never thought of looking those up on Flickr, even though I’m in several groups. =’)
September 22nd, 2008 at 3:13 pm
I am so entering the contest.
I’m so in need of a good quality thermal bento!
I have a no name brand that I found at our local Ross store (similar to Marshall’s). Its pretty tiny and holds about a bowl of soup or stew (kinda perfect for my lunches). My one thing that I love love love to pack is beef stew! I do use the rice lid method (great tip, biggie!). It does its job and keeps my lunch warm until lunchtime. Its turning into the rainy season here in HI and its great for rainy lunch hours in the office. It just makes me all warm and fuzzy to have something hot to eat!
but really, if I had a state of the art thermal bento, I’d pack EVERYTHING in it. My most favorite food in the world is coleslaw and I’ve never packed it in a bento because its gross if its not ice cold.
September 22nd, 2008 at 3:25 pm
I just love all of my thermal bentos. I own the Mr., the Ms., and a Hello Kitty thermal kit.
My favorite meal to take is a taco salad in the Mr. that I eat cold and pack cold. I pack taco meat in the bottom (soup bowl); iceburg lettuce (rice bowl); taco cheese and salsa (veggie bowl); and corn chips in the top bowl.
September 22nd, 2008 at 3:32 pm
The only thing that bothers me is that both the hot and the cold temperatures are in the danger zone for food safety.
September 22nd, 2008 at 3:42 pm
Thanks for the contest and for all the info. on thermal bentos! After finding your website, I have purchased A LOT of bento supplies for my kids - laptop lunch boxes, Hello Kitty bentos, Ichibankan bentos, you name it. But what I use the most is the thermal Hello Kitty lunch jar by Thermos for my daughter. She loves warm food, esp. noodle type foods. The best thing she says I packed for her so far is the seafood alfredo sauce penne pasta dish I made by adding cooked salmon and shrimp to Regu’s store-bought alfredo sauce. She says that was her favorite so far and wants more. I also like to pack pesto pasta, korean jap-chae or even mac and cheese.
I would love to win a real Mr.Bento kit! Count me in and thanks again for all your attention to all things Bento!
Cheers,
Sue
September 22nd, 2008 at 4:14 pm
I live in Louisiana- and with gumbo weather right aroung the corner I would pack gumbo, rice, potato salad (warm, of course) and bread pudding with whiskey sauce. I’m feeling all warm and cozy thinking about it!
September 22nd, 2008 at 4:29 pm
I absolutely love the idea of taking soup for lunch. It is so good for you, filling and healthy if you stick to the broth based soups (rather than the cream based.) I also have to include nori-maki with furikake (rice balls with seaweed sprinkles.) They are my favorite bento item. Thank you for the info.
September 22nd, 2008 at 4:36 pm
We love our Mr. Bento…of course, that means my husband loves to take it to work! I’d have to say that his favorite dish is chicken dumplings, onigiri, and spinach salad.
September 22nd, 2008 at 4:53 pm
Perfect timing! I just got a Ms Bento from our local Japanese market. I used it for the first time tonight for soup, and noticed that the bowl leaked. After reading your review I know that’s normal. If I won the Mr. Bento from Lunch In a Box I would pack MORE food in it for me! Ms. Bento is okay for Muffin but too small for me!! And now I want my very own.
September 22nd, 2008 at 5:16 pm
it’s soup. that’s my favorite. any kind, but beef vegetable is my current bff.
September 22nd, 2008 at 5:33 pm
Thanks for the comments with your favorite foods. Please be sure to put them on the actual giveaway post linked above, as only comments there (not here) are eligible for the giveaway.
September 22nd, 2008 at 6:20 pm
Very helpful review. Thanks!
And as for packing–my favorite fall thing to pack in such a container would be hot, homemade applesauce. It makes such a difference to have it still warm when eating it.
September 22nd, 2008 at 6:38 pm
i’ve been wondering about this product for some time and would LOVE to win it. i make soups all the time, and need something to carry the leftovers.
September 22nd, 2008 at 6:53 pm
I don’t have one, so I don’t have a favorite, but I think that any curry dish would be great to pack in it.
September 22nd, 2008 at 7:00 pm
Well I think if I were to pack a lunch in one, I’d put some sort of soup in it
I mean, that’s impossible w/ regular bento boxes whether it’s possible to reheat it or not.
September 22nd, 2008 at 7:33 pm
I’m really enjoying your site, and learning more all the time. Food preparation has been a challenge for me as a celiac, and I would LOVE to win your giveaway. Thanks for having it!
I would pack soup, always soup….rice balls, spinach salad with toasted almonds and mandarin oranges.
September 22nd, 2008 at 7:51 pm
Soba and salmon cakes.
September 23rd, 2008 at 1:36 am
I would put homemade chicken noodle soup in. There is nothing better than homemade noodles!
September 23rd, 2008 at 4:39 am
My husband should be very happy with a thermal jar. He always complains that he has no time to eat…
His your contest open to Canadians? If so, I’m in!
Sophie
September 23rd, 2008 at 4:43 am
Chicken curry and rice. Hands down my favourite thing to put in a thermal bento.
September 23rd, 2008 at 6:18 am
@23 from Sophie: Yup, the contest is open to Canadians. Feel free to leave a comment over at the separate giveaway post to enter: http://lunchinabox.net/2008/09/22/mr-bento-lunch-jar-giveaway/ Comments on the review itself (here) do not constitute giveaway entries.
September 23rd, 2008 at 7:06 am
I would make a chicken pot-biscuit: cook inards of chicken pot pie in oven till thickened, then make biscuits and place on top. The thermal will keep it nice and hot till lunch. I’d put some extra steamed veggies and edamame (maybe a few crackers) in the middle and a fuit salad with greek yogurt on top.
September 23rd, 2008 at 7:30 am
I bought one of these but i’m always afraid to bring soup in it. Thanks for your advice, as usual!
September 23rd, 2008 at 8:09 am
I’ve been wanting a thermal lunch jar for a while. I love soup for lunch in the winter and with multiple containers I could pack soup and a sandwich and some fruit or veggies. Or curry rice.
September 23rd, 2008 at 8:20 am
Mmmmmm, nothing nicer than venison stew and rice pilaf in the middle of a drizzly fall day. I recently bought a barely insulated lunch pack for my husband (the only one of us without a bento box or a laptop lunchbox). I think a thermal one would be even better, because then he’s have no excuse to live on coffee, bananas, and junk food from the vending machine. Thanks for giving one away.
September 23rd, 2008 at 8:26 am
I like to either cook the mini frozen chicken pot pies and stick them in there or take leftovers from a larger pot pie for dinner; Flaky pastry? Chicken? Gravy? YUM
September 23rd, 2008 at 9:00 am
I would pack some yummy chili and some toppings. A nice side of rice would be a perfect dinner on the nights I have to work.
September 23rd, 2008 at 9:40 am
Thanks so much for this in-depth post. I’ve been debating which (and if) to get for a while now. My DH leaves at 5am and eats lunch at 12. While I don’t want to get up to heat stuff up at that hour, once in a while would be nice for him. That pulled pork? sandwich idea looks great!
September 23rd, 2008 at 12:03 pm
The four tiers of this insulated lunch jar make it perfect to feed a hungry child all day long. I can pack my son a morning snack, lunch and an afternoon snack all in the same container.
For kids who participate in after school activities, the Mr. Bento makes that all important pre or post soccer snack available and fresh!
September 23rd, 2008 at 12:47 pm
Great review! I have the Ms. Bento and my daughter’s favorite is alphabet soup with a few chunks of sourdough bread for dipping. Will definitely check out the Flikr group for more ideas! Thanks.
September 23rd, 2008 at 1:31 pm
I have never had a warm lunch except in elementry school when we had pizza or burgers once a month. I would love to be able to bring some hot chili to warm me up this winter in COLD Alberta!!
September 23rd, 2008 at 5:46 pm
Snappiness, the two container Ms. Bento is not leak-proof. Which one do you have? If it’s the three container one with the soup bowl that’s leaking, you should call Zojirushi at 1-800-733-6270.
I usually pack yogurt or cottage cheese for breakfast in my soup bowl. Salad in the rice bowl, fruit salad in the bigger side dish bowl, and some kind of protein in the small side dish bowl.
September 23rd, 2008 at 10:22 pm
Great review on thermal jars!
I’d probably buy the knock off jar because of its size, the others look huge but I would maybe buy a smaller one if I could find it
The large set would be great for taking a lunch for 2 people, and i’ve taken people food when they are sick and that would be great too
The name brand jars would also be great for a trip since it keeps food warm/cold a lot better than a cheap one
I love the utensils case, that is a great touch
I think overall I would get mroe use out of them in the winter, thats when I make a lot of soups and hot dishes and I love to bake in the winter too!
September 24th, 2008 at 2:25 am
Wow! You didn’t leave out any details! Hmmmm…what would I pack? Maybe something sweet & spicy. Probably some kimchee fried rice and a warm dessert…like peach cobbler!
September 24th, 2008 at 5:50 am
You know I’m in for a cool contest! My fave things to pack into one of these is my curry potatos (which is SUPER easy to make) and also my weird turkey alfredo pasta mix that really has no name. It’s really easy to make too. It’s made with ground turkey. Just a weird combination of yummy ingredients I threw together one night and my family has loved it ever since. If you want the recipe, just yell!
September 24th, 2008 at 7:38 am
thank you, thank you, thank you.
i have been wondering lately how these stack against each other. i could buy the nissan locally but would have to order the mr. bento. this is terrific!
did i say thank you?
September 24th, 2008 at 10:12 am
@4 from LillyAnn: Glad you like the post! I kind of feel like I just delivered a baby, it took me so long to write this one…
September 24th, 2008 at 10:16 am
@8 from kastinkerbell: If you start with even colder or hotter food and prechill/heat with salted ice water or boiling water, the food’ll stay out of the danger zone for longer. Just to be safe, though, best to avoid packing easily spoiled foods like dairy, and maybe include foods with antibacterial properties (see my post on food safety for a list).
September 24th, 2008 at 10:29 am
@16 from Holly: Golly, I haven’t had hot homemade applesauce in years! So nostalgic. BTW, be sure to put your entry comment on the other giveaway post (not this one) to be eligible for the giveaway.
September 24th, 2008 at 10:34 am
@35 from islandveggie: For the best heat retention, you might want to check out the all-metal thermal food jars from Thermos Nissan. I haven’t run a proper test on them yet, but I think they keep things much hotter for longer than the thermal lunch jars.
September 24th, 2008 at 6:50 pm
Awesome review! The level of detail is great. One of my friends just bought a Mr. Bento and I’ve been thinking about getting one, too - it’s so much more compact and easier to pack than loose tupperwares.
September 24th, 2008 at 7:03 pm
My fave thing for a thermal is pretty lame…. tea! I use my HK thermal for tea or udon soup pretty regularly! YUMM
September 25th, 2008 at 4:31 am
WOW! Thanks for the breakdown. I have a random food jar that I won on haiku your blog and it seems to be enough food for me and the hubs for lunch. We love it!
September 25th, 2008 at 9:01 am
Love your portion/sizes. does it really keep food warm?
September 25th, 2008 at 9:38 am
Just a (late) comment- someone else might have said the same thing. We have the Nissan thermos lunch jars and use them constantly, though they really can be too much. I don’t usually like ‘make your own sandwich’ (though the taco salad idea is nice.)
We either pack a morning and afternoon snack (so only eat one or two layers at lunch), or I use the bottom watertight layer to hold ONLY hot or cold water, to keep the whole jar hot or cold. I once tried packing ice cream, but it didn’t work when my husband left his Bento out in the sun. Sometimes (on an overnight shift) I’ll pack a dinner and a breakfast.
I have found the whole jar needs to be hot or warm food, or the whole jar needs to be cold food. I started out packing cold food on top and hot on the bottom and got a lot of mush. All hot and all cold work well, though.
September 25th, 2008 at 12:16 pm
I’ve been thinking to buy a Mr. Bento but hesitate because of the price. I’ll love to win one.
p.s. I absolutely love your blog.
September 25th, 2008 at 1:10 pm
We love any kind of pasta for hot lunches, and any kind of leftovers!
September 25th, 2008 at 1:32 pm
I sent a friend of mine over to check out your blog…she has twins in school and needs lunch ideas. I told her that she would find plenty here, but I was kind of sad b/c that would probably mean I wouldn’t hear from her for about a month until she got through all of your posts
Thanks for your review!
September 25th, 2008 at 2:11 pm
@48 from julie: Yup, it keeps food warm. Check out my heat retention test results in the table at the bottom of the post for details.
September 26th, 2008 at 8:43 am
I just found your website because I need to pack healthier lunches for my kids. But this Mr. Bento would work wonderfully for me. It would be anything on top of brown rice or whole wheat pasta. Yum!
Great website!
September 27th, 2008 at 11:57 am
I’ve been wanting to buy one of these for ages, but I wasn’t sure which one to get. Thank you so much for making that decision easier!
September 27th, 2008 at 4:46 pm
I’ve just started learning about Bento boxes and I’m excited at the idea of packing lunch and snacks altogether. I would pack some soup (probably roasted tomato bisque…yummy), some cooked chicken with a little pasta, spinach salad and some nuts and fruit to nibble on as snacks during the day. Great site and reviews, thanks!
September 29th, 2008 at 7:45 am
Really in depth, I’m surprised at the heat retention. To be honest while I found my Mr. Bento to be great the um, one time I used it, I didn’t think the heat retention would be so high. Shows what I know about temperatures I guess
September 29th, 2008 at 9:23 am
I’ve always thought the concept of a meal in a jar was neat and I think I’m going to start researching some more to find the right model for my lifestyle. Great article, it really helped me to pinpoint what features I want and don’t want.
October 1st, 2008 at 5:17 am
I don’t own a thermal bento box, but with the winter coming up, this review is quite timely. Oh, and thanks for the chance to enter and win one for myself.
As for me, I have two favorite packed lunches. The first is chicken curry with a side of rice. The other I love is when I pack is my own instant soup. I will steam a bunch of veggies and then put them in a container with a ball of miso. When it is time for lunch, I boil some water, pour it in, and mix it all together.
October 1st, 2008 at 6:01 am
Great review! thanks!
October 3rd, 2008 at 1:33 pm
Pasta salad! Can’t get enough of it, and it works both hot and cold…
October 3rd, 2008 at 6:09 pm
3 color soboro bento. With 3 color fruit (kiwi, strawberry, mango) for top container.
October 5th, 2008 at 12:26 pm
I like any kinds of soups or stews.
October 5th, 2008 at 3:01 pm
Thanks for the comments with your favorite thermal lunch jar dishes; just a reminder that the comments need to go on the other giveaway post to be included in the giveaway: http://lunchinabox.net/2008/09/22/mr-bento-lunch-jar-giveaway/ Today’s the last day for entries!
November 1st, 2008 at 6:48 pm
Love the comments and comparison.
November 8th, 2008 at 4:19 pm
Hi, I have become very concerned about plastic containers, and BPA leaching more specifically. I have scoured the web to try to figure out what kind of plastic Mr. Bento uses in his bowls….have you ever investigated this? the user manual doesn’t seem to have any information…..I’d LOVE to use the Mr. Bento lunch jar, but would like to make sure it’s super safe?
Thanks!
November 24th, 2008 at 9:44 pm
Hi,
Since you have a toddler, I’m hoping you might have thoughts on this….I’m looking for a thermal jar that my 3 year old might be able to open without assistance (I’m fine with practicing with her). Her school encourages us to send her with containers that she can open herself (just for confidence not b/c they’re lazy) and I haven’t seen too many easy open thermal jars. I’ve checked out some of them - some she can open the outside but not the inside plastic containers.
Anyway, any suggestions? Love your site.
January 6th, 2009 at 5:15 pm
Where can I buy this thermal lunch jars
May 2nd, 2009 at 5:35 pm
Can you tell me what type of plastic the containers are made of in the Nissan thermal system? I’d REALLY appreciate it!
June 22nd, 2010 at 8:20 pm
I wondered if the Tiger mini stainless thermal bento jar is similar quality. A smaller quality one would be wonderful.
March 3rd, 2011 at 4:11 am
Hi, I just read this and I have a bit of additional information you might want to include in your heat test info. I’m a chemistry major and while reading this i noticed that you only used water in the bowls to test the heat retention. Water has the highest specific heat of any common substance which means it takes a lot of energy for water to change temperature up or down. Although soups, stews and curries are mostly made of water but foods containing little water, are likely to be much more susceptible to heat loss. I hope to buy a Mr. bento or Thermos Nissan in the future because I love curry but I’m always too much in a rush to heat it up at a microwave.
July 10th, 2011 at 5:31 am
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August 28th, 2011 at 6:01 pm
[...] got Price Protectr tracking the price of a Ms. Bento thermal lunch jar*for me (see Lunch in a Box for more info on thermal jars). I’m intrigued by these because they keep food warm, and it [...]
September 3rd, 2011 at 4:09 pm
How does the plastic on the Mr. Bento hold up against use with metal eating utensils? I use a pair of titanium chopsticks, and some plates don’t even hold up properly…
September 4th, 2011 at 9:32 pm
Thanks for your great and very detailed review. I would like to know if putting empty small and/or medium bowls in the jar with filled rice and soup bowls, does this have any effect on the heat retention?