Thermos FUNtainer Stainless Steel Food Jar Review

We purchased the Thermos FUNtainer Stainless Steel Food Jar so our expert reviewer could put it to the test when making school lunches. Keep reading for our full product review.

If you pack school lunches on the regular, you likely go through a lot of Ziploc bags and Saran wrap. If you’re looking to cut back on single-use plastics or your kids have just grown tired of sandwiches, maybe it’s time to consider an insulated thermos like the FUNtainer 10-ounce food jar. The container, which comes from Thermos itself, allows you to pack, soup, pasta, and oatmeal without worrying if your child will have a way to warm it up come lunchtime. To see if the FUNtainer lived up to our high expectations, we got to assessing its design, heating capacity, care, and more. Read on to see how it fared. 

Design: Perfect for kids 

Thermos makes a wide range of hot and cold food containers, so you have plenty of options if you’re in the market. Due to its size, design, and aesthetic, the FUNtainer is ideal for school-age kids. While we tested a solid purple version of the thermos, it’s available in nearly thirty colors and themes from Frozen and Toy Story to Paw Patrol and The Secret Life of Pets. 

The 10-ounce container is lightweight and at 12 x 8.4 x 5 inches, it’s easy for small hands to hold. Additionally, it has a simple twist-off lid that’s easy for kids to maneuver and a large mouth that’s easy to fill, eat from, and clean. With a condensation-free, stay-cool exterior, you also don’t have to worry about the container being too hot or cool for your little one to handle. 

Material: Sturdy stainless steel 

Despite being lightweight, the FUNtainer is sturdy and durable, so we’d have no concerns about it getting bumped around in a backpack day after day. The cylinder is made from stainless steel and the lid is BPA-free plastic. The plastic on the lid makes it easy to twist off even with wet or food-covered hands and inside, a flexible gasket ensures it’s tight and leakproof. 

To truly test the thermos’ durability, we dropped it down a flight of stairs and let it roll around on the floor of our car just to see what would happen. We were pleased to find that it successfully handled each challenge and came away without any dings or nicks. We’re confident that the thermos will perform well against the rigors of a daily commute whether that be in a car, on a bus, or on foot.

Heating Capacity: Delivers on its advertised promise 

According to the FUNtainer product listing, you can expect the thermos to keep your food hot for 5 hours or cold for 7 hours. That’s long enough to go from early morning to lunch—especially if you don’t open the FUNtainer in between. The container does this with the aid of two stainless steel walls. Between the inner and outer chamber is a very thin empty space; this space doesn’t conduct heat, which creates a barrier between the hot or cold substances in the mug and the air outside. 

While the FUNtainer uses the same technology as every other insulated mug on the market, we wanted to see if it held up to its specific promises. To do this, we first filled the thermos with mac and cheese that was still piping hot from the oven. The rest of the test was simple; we opened the container every hour after that and took a bite. Hour after hour—all the way up to the 5-hour mark—we found our mac and cheese was still nice and hot. While it wasn’t fresh-out-of-the-oven hot, it was warm enough to eat without being reheated. If you’re willing to compromise on temperature and are fine with warm pasta as opposed to hot, you can even push it to 6 hours. 

If you plan on using the FUNtainer for cold drinks, you’re also in luck. In our testing, the FUNtainer kept ice water freezing cold for 7 hours. The only issue here is capacity. Since the FUNtainer is only 10 ounces, you’ll likely need a larger insulated travel mug if you want to carry a smoothie or iced coffee. 

Care: Somewhat tedious

The FUNtainer loses a few points when it comes to cleaning. The product listing states that you can “Pop your FUNtainer food jar in the dishwasher,” but “washing by hand is recommended.” While you can wash the FUNtainer in the top rack of your dishwasher without compromising the integrity of the product, hot water and/or abrasive soaps can damage the appearance of the thermos. 

We didn’t want to risk aesthetic damage, so we chose to heed Thermos’ warning and wash it by hand. To get a really thorough clean, you first have to remove the o-ring gasket from the lid. If you don’t, residual food and liquid can cause mold to grow. Once you seperate them, you can wash each piece individually.  

Washing the main container was a breeze, but the lid was more challenging as there’s a ring of space (where it screws onto the main container) that’s too small to wash with a sponge. If food gets stuck inside the ring, you’ll need to find a creative way to clean it. We sprayed our thermos with hot water and then cleaned the ring with a cotton swab. While our method worked just fine, it would be a pretty annoying task to do daily.

Price: A fair price for a good product

The Funtainer isn’t the fanciest or most unique insulated food container on the market, but it works well and comes in a variety of colors so kids can choose their favorites. And since it’s only $16, we’d feel fine about sending it to school in a lunch box. It’s leak-proof and durable, so it’s a smart choice for energetic kids. It’s also one of the most affordable insulated food containers available from Thermos. 

Competition: Loads of options from Thermos itself 

Thermos Stainless Steel King Food Jar: If the FUNtainer’s 10-ounce capacity just doesn’t cut it, try Thermos’ King Food Jar on for size. The 16-ounce jar, which goes for $25, comes with a full-size fold-out spoon along with its increased capacity. 

Thermos Foogo Stainless Steel Food Jar: We tested both the FUNtainer and the Foogo and honestly, we didn’t notice much of a difference between them. The Foogo container has a design that works for both kids and adults, but the FUNtainer was able to keep our food hot for an hour longer. They both retail for just under $20 and each has a 10-ounce capacity, so the decision here really comes down to which pattern or color you prefer.