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Reviews > Cook and Food Storage Gear > Utensils > Primus Lunch Jug > Test Report by Suzi Gibson

Primus Lunch Jug

Test Series by Suzi Gibson
Initial Report - 10 November 2008
Long Term Review - 25 February 2009

Tester Information:

Name: Suzi Gibson
Age: 30
Gender: Female
Height: 5'6" (1.7 m)
Weight: 155 lb (70.3 kg)
Email address: suzi_q_jones at yahoo dot com
City, State, Country: Anderson, South Carolina, USA

Backpacking Background:

I've gone on many family camping trips to various places along the east coast of the US since I was a child. The backpacking bug was always there, whispering in my ear until finally in my early twenties it bit me! I've since done several backpacking trips in Florida, Washington, Virginia, and North Carolina. I typically backpack with around 30 lb (13.6 kg) of essential gear (sleeping bag and mat, tent, stove, and clothes), food and water and usually go for 2 to 3 days. My current tent and bag comprise almost half of the pack weight.

Product Information:

Manufacturer: Primus
Year of Manufacture: 2007
Sizes Available: 11.8 oz (0.35 l) and 16.9 oz (0.5 l)
Size Tested: 16.9 oz (0.5 l)
Listed weight: 12.5 oz (355 g)
Weight as Delivered: 13.0 oz (368.5 g)
Listed Dimensions: 3.3 in (85 mm) x 6.5 in (165mm)
Actual Dimensions: 3.3 in (85 mm) x 6.5 in (165mm)
Listed Volume Held: 16.9 oz (0.5 l)
Actual Volume Held: 17.0 oz (0.5 l)
MSRP: $15.00

Initial Report

Product Description & Initial Impressions:

I received the 16.9 oz (0.5 l) Primus Lunch Jug (hereafter, lunch jug) for this test series. The lunch jug is a vacuum-sealed thermos with 18/8 stainless steel double walls. The outside wall has a black powder coat finish, which is supposed to provide a little extra grip. The inside wall is not painted. The lunch jug's mouth is indeed wide at 2.75 in (70.0 mm). The inner dimensions are capable of storing an unopened 10.5 oz (298 g) can of condensed soup just in case I plan on heating up some soup on the trail. There is a plastic seat on the base as well as at the base of the neck. In addition, the cap and threads are also plastic. The threads themselves are wide which should prevent mis-threading. The o-ring is fairly thick and appears to be made of silicone. It is also seated snug in the cap.

Primus 0.5l Lunch Jug
It should be noted that there is a discrepancy between the listed dimensions for the 16.9 oz (0.5 l) jug.

Primus Website

Lunch Jug Retail Packaging

Actual Dimensions


6.7 in (175 mm)

6.5 in (165 mm)

6.5 in (165 mm)


3.3 in (85 mm)

3.3 in (85 mm)

3.3 in (85 mm)

Primus Lunch JugCare and Cleaning:

There were no care or cleaning instructions given nor was there any indication if the lunch jug is dishwasher safe. Therefore, during the test series I will hand wash the lunch jug after use instead of letting the dishwasher do the work for me. This really shouldn't be too bad since there are only three parts to the jug: the base, the top and the o-ring and it does have a wide mouth.

Test Plan:
Primus Lunch Jug

Primus supplied a time series graph on the lunch jug's box detailing their findings for content's temperature retention. They also state "Liquid filled at 95 C (203 F) is still warm (60 C/ 140 F) after approx. 5 hours". I will conduct my own simple home testing to quantify how long the contents stay warm. These findings will also give me a better idea of how long I can expect contents to stay warm on the trail. This is important to me since the hikes that I really like to do are 1 - 2 hours away. I want to be confident that the contents will stay hot during the drive as well as on the trail. There will also be lots of trail time in the Carolinas, Maryland and Florida! Over the course of field testing, I will investigate the jug's ease of use, heat retention, ability to maintain a tight seal and packability.


My initial impression is that the lunch jug looks rugged, ready for some trail fun. The integrity of the plastic lid is a bit of a concern. I'm curious how the lid will perform during the test where it will inevitably become victim to accidental drops on the trail. However, the subtle grip from the powder coating should help me keep the lunch jug in my hands on not on the trail. I'm impressed with the wide mouth and I think it'll be fairly easy to pour liquids (including chunky soups) into the lunch jug as well as eat and drink from it. Cleaning on the trail or at home should also be easy given the wide mouth. The lunch jug's compact size should allow it to pack easily into my child carrier or lumbar pack for a day's outing.


  • Wide mouth
  • Compact size
  • Powder coat grip on the exterior of the jug


  • Plastic lid is a pre-testing concern

Long Term Report

Field Locations and Conditions:

Over the past 2 months, I have used the Primus Lunch Jug (hereafter, lunch jug) on several day hikes as well as one bike ride. Some of the hikes included part of the Carolina Foothills Trail (South Carolina), part of the Bartram Trail in Tuskegee National Forest (Alabama), Gulf Islands National Sea Shore (FL), and a series of private trails in Maryland. Elevations traveled ranged from sea level to 3000 ft (914 m). Temperatures ranged from approximately 40 F (4 C) with snow flurries, to 80 F (26 C) and sunny.

Home Testing:

Before heading out in the field, I conducted a series of tests at home to see how long the contents would stay hot in a controlled setting. My rationale for this was due to Primus' reported findings on their retail box. Their testing was conducted with an ambient temperature of 65 F (18 C). I was curious to see if there were any differences between their results and those produced from a colder and more probable Fall/ Winter hiking temperature scenario of 38 F (3 C). In all tests, I followed the manufacturer's recommendation to prime the lunch jug by adding hot water for 5 minutes, then draining the hot water and adding the desired contents. In the first test series, the contents were 190 F (88 C) water. The lunch jug was then placed in the refrigerator (38 F/ 3 C) and the temperature was checked hourly with a digital thermometer. At 8 hours, the contents were 100 F (38 C) which was approximately 30 F (1 C) less than what was reported in the graph on the box. I also investigated the temperature change over a nine hour time period where the lunch jug was only opened at the end of the time period. In this test the contents were 200 F (93 C) water. The lunch jug was then placed in the refrigerator (38 F/ 3 C) and allowed to sit unopened for 9 hours. At 9 hours, the contents were 101 F (38 C) which was approximately 20 F (7 C) less than what was reported in the graph on the box and 12 F (11 C) less than the temperature recorded at nine hours in the hourly test. I concluded that the lunch jug does keep its content's warm in a 'cold' environment however, not as warm as the box claims. Again, this is more than likely due to the differenced in ambient temperatures used to test the lunch jug's heat retention.

Field Performance:

During cold hike testing (<60 F/ 15 C), I packed tea and chunky soups into the lunch jug. Before hiking, I followed the manufacturer's recommendation to prime the lunch jug by adding hot water for 5 minutes, then draining the hot water and adding the desired contents. I was unable to do this on one hike and did notice that my tea did not stay warm nearly as long as it had on other hikes. Also of note, there was no heat transfer noted on the outside of the lunch jug. All of the warmer hikes (>60 F/ 15 C) were impromptu and I merely filled the Primus Lunch Jug lunch jug with water from my refrigerator's cold-water reservoir. The lunch jug did not disappoint and kept my drink cold throughout the hikes.

The lunch jug packed nicely into my child carrier and lumbar pack, as well as a small daypack . The exterior coating did enhance the lunch jug's 'traction' and helped keep it in my hands more than other beverage containers I've hiked with. It also held up well on the few occasions where I tripped and it went airborne. The wide mouth made it easy to fill with liquids and chunky soups as well as consuming them. Cleaning the lunch jug at the end of the day was very easy. The wide mouth allowed easy access for wash cloth or a bottle brush.  

Now for the lid. I had concerns about the lid prior to testing (see IR above). Even though the lunch jug took a couple of tough falls, the lid held up and did not crack or break, which was an initial concern I had. I did notice that the grips on the lid did not provide as much traction for my hand when unscrewing and screwing in the lid. The traction was notably worse when I tried to open or close the lunch jug with gloves on. I wasn't happy about having to take my gloves off on the cold trips just so I could get a drink. There was also a noticeable amount of flex in the lid. I also noticed that it was fairly easy to screw the lid on incorrectly, almost cross threading the manufacturer's threads. Unscrewing it when this would happen was usually not as easily done. Even when properly screwed on, the lid seemed to have two different stop points. The first stop seemed to be secure however, there usually was a small amount of leakage. The second stop was usually ¼ turn past the first stop and held the contents securely. This really bothered me on the cold hikes when I was trying to screw the lid back on with gloves on.


Even with the lid's quarks, I think the lunch jug does its job done and it kept this hiker warm on the inside during the cold hikes as well as providing a refreshing cold drink on the warmer hikes.


  • Insulating capability for both hot and cold contents
  • Packability for day trips
  • Wide mouth for easy filling
  • Traction on the exterior of the jug


  • Lid (lack of traction, sealing quirkiness)

This concludes my Long Term Report for the Primus Lunch Jug. Thanks again to Primus and for granting me the opportunity to test the Primus Lunch Jug.

Read more reviews of Primus gear
Read more gear reviews by Suzi Gibson

Reviews > Cook and Food Storage Gear > Utensils > Primus Lunch Jug > Test Report by Suzi Gibson

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