Reviews > Cook and Food Storage Gear > Utensils > Primus Lunch Jug > Test Report by Kathryn Doiron

Primus Lunch Jug

Product Information:

The Primus Lunch Jug is an insulated jug that can contain hot or cold beverages. The jug is black on the outside and powdered steel on the inside. The body of the jug is metal but the bottom outer cap is plastic as is the whole lid. The lid is a plug seal lid, meaning the inside of the lid acts like a plug when the jug is closed. As such, the lid cannot be used as a cup. There is an opaque sealing ring around the plug that seals the jug. Inside the jug, there is a ring of raised metal that I assume helps with the sealing of the jug. I received the 16.9 oz (0.5 L) jug. The jug has external threads to receive the lid. The threads are not sharp. I will look into how the threads affect drinking and pouring from the jug.

Based on the website, the jug is what I expected. I feel it is about the size I was expecting and seems to be about perfect hand sized for me. It is too large to stick in a bike bottle holder but seems to be about comparable in size to the large mouthed, rigid plastic drinking bottles currently on the market. I will be checking to see if it will fit in the external water bottle pockets on my backpack.


Close up of the outer threads plus the metal interior. The raised metal ring can also be seen.

I will be using this jug to not only carry hot or cold beverages but to also assist in cooking meals. I will be testing how long the jug can keep things hot and cold both when the item is placed inside a room temperature jug and when it is placed in a pre-chilled, or pre-warmed jug. Priming most thermal item helps to keep the items at the desired temperature longer. I will be interested to see if that is also the case with the jug.

Based on initial use, I feel I have to screw the lid on tighter than I think I should. I filled the jug with cold water then tossed it in my daypack for a bike ride. The jug kept the water cold as expected, but the jug leaked a little. The leakage was not due to water caught in the threads as I poured water directly into the jug from a pitcher. The leakage was minor but something that I will be aware of in future when carrying and using the jug, especially on a trip with gear that I want to remain dry.

My test plan over the next couple of months will be to use the Primus lunch jug on all my outdoor activities. This will include backpacking, day hiking, trips in the George Washington National Forest and the Shenandoah National Park as well as occasionally biking along the Potomac River. I will be interested in looking into how well the jug stands up to wear and pack abuse as well as how water tight it remains with hot and cold beverages.

I have used this jug on a mixture of day hikes, a few car camping trips as well as backpacking trips to have some hot tea or hot cocoa with my lunch when I stop. The weather has been cold enough that this is just as much a luxury as a comfort. I have taken it out on a total of 4 day hikes, 2 car camping trips and 2 backpacking trips over the course of the 3 month test period. The contents of the jug have ranged from water to soup to both hot and cold beverages.

Trips:
The first time I took the jug out with hot tea, I noticed that the outside of the jug was cold to the touch. I thought this wasn't going to bode well for me getting hot tea, but when I opened the jug, steam rising off the surface reassured me that the tea was still going to be warm. I was pleased that the tea was still very hot after at least 2.5 hours in the jug. I had made the tea with fresh off the boil water, and sealed the jug almost immediately. I did the same with some cocoa and burnt my tongue on the hot cocoa after the same 2.5 hour hike. Air temperatures were around 39 F (4 C). I noticed that while the outer metal part of the jug was cold to the touch, the lid was just a little warm to the touch.

I took the jug out on a three day, two night trip. The elevation loss the first day was 2000 ft (610 m) and temperatures went from a high of 45 F (7 C) to a low of 32 F (0 C) over night. I carried the jug empty and had every intention of using it to cook meals in. It is a good thing I lined the jug with a plastic bag before dumping in my meal as I quickly discovered the jug was just a little too small for this particular meal. On the second night, I used the jug as a drinking vessel for eggnog. This worked out quite well.

The next day hike, I used the jug for tea as I knew the temperatures would be cold enough that a warm drink would be appreciated. I made the tea around 8:00 am by pouring in fresh off the boil water into the jug, dropping in a tea bag and some sugar then closing it. I didn't have a chance to drink the tea until almost 1:00 pm. At this point the temperatures were about 24-30 F (-4 to -1 C) out, and much colder in the wind. The tea was still warm but not warm enough to burn my lips. The outside metal part of the jug was freezing cold to the touch which was a little unnerving as I assumed I was going to have frozen or iced tea. This was not the case, but I think I pushed the limit of the jug. If I have a chance to duplicate this condition, I would like to prime the jug first to see if I get better heat retention.

I took the jug with me on an overnight trip with the hopes of having hot tea for lunch as I was expecting 40 F (4 C) weather. I prepared my tea around 8:00 in the morning and primed the jug with hot water from the tap while waiting for the water to boil. Once boiled, I dumped the tap water and poured in the boiling water, plus sugar and tea bag than sealed the whole thing up. I have been placing the jug in my pack upright just in case of drips, but my pack was placed in the car laying down and I didn't notice any leaks or wet spots. Come lunch time, I unfortunately forgot about the tea. I eventually remembered it at camp around 5:00 and opened up the jug expecting iced tea. To my surprise and delight, the tea was still warm. I didn't have an immersion thermometer so I would class this as just warmer then body temperature, not hot or hot enough to burn. A few degrees cooler and it would have been tepid. A few of us enjoyed the tea before setting up camp.

The next trip was out to the George Washington National Forest and was a car camping trip with day hike and the jug was mostly used as a drinking cup. Another day hike saw me making some hot chocolate before a long cross country skiing day. I prepped the drink around 7:30 and didn't get around to drinking it until around 2:30. Temperatures for the day were just above freezing and it rained most of the afternoon. The drink was still warm but no longer hot. I couldn't drink it all so the rest remained inside until I could clean it up later.

Another day hike, I took the jug on was a 6 mile loop hike in the Shenandoah National Park. I didn't have anything available for lunch so I heated up some left over soup and dumped it into the jug. Temperatures that day were around 45 F (7 C). The jug did a great job of keeping the soup warm and the way the jug fit in my hand and the comfort of the threads at the lip, made it easy to eat the pureed soup. The soup was not as hot as I could have heated it, but the jug did keep it at about the same temperature for the 5 hours to lunch time.

The last time I used the jug was on an overnight car camping trip. As the jug keeps hot stuff warmer longer then a regular camp mug, I was planning on using it for drinking hot liquids. What ended up happening at the end of the night, I dumped in the rest of my ice cold water into the jug to store overnight. The next morning I found that some of the water had actually frozen in the jug. I later found out that the overnight low was -24 F (-31 C). The water wasn't frozen solid, but it was just starting to form crystals on the water surface and sides of the jug. It was interesting to see but I was pleased that the water wasn't frozen solid like the rest of my water was.

Impressions and Comments:
I have used the jug with various herbal teas plus sugar, hot chocolate, soup, eggnog, oatmeal, and water. I do notice that anything with flavour tends to impart an odour to the plastic parts of the lid. But while the lid tends to pick up odours, it doesn't seem to impart any tastes to the next beverage contained. The stainless steel inside has been very easy to clean, while the lid does require a little more effort to get it clean all the way up the threads. After 3 months of twisting the lid on and off, the seal is still tight with no signs of leakage or wear.

I like the jug diameter as it is a perfect fit with my hand size. I also like that it fits nicely in the water bottle slot on the side of my day pack. I find that the 16.9 oz (0.5 L) size is a bit much for me to enjoy in one sitting. But I find that everyone likes to have a sip so I have plenty to enjoy and still have some to share with other hikers. I had hoped to use the jug for both enjoying drinks and cooking small meals in it. The jug is just a little too small to accommodate the Lipton Knorr Noodles or Rice that I generally enjoy for supper. But it was the right size for morning oatmeal or evening eggnog. I have been finding that as long as I leave the jug tightly sealed, contents maintain a good temperature for about 3.5 hours (closer to 5 with priming), after that the loss becomes very noticeable. At about the 7 hour mark, things are lukewarm and are no longer hot enough to burn my tongue. This was mostly observed with outside temperatures around 35 F or above. Colder external temperatures did have the contents cooling a little faster. 5 hours at 45 F (7 C) saw the contents (soup) still hot enough to enjoy, while 5 hours at 24 F (-4 C) saw the contents (tea) lukewarm. This was comparing a thick soup to a tea. The tea was made with boiling water, while the soup was reheated and hot to the touch. The tea cooled faster in the colder temperatures then the soup did in the warmer temperatures.

I didn't care for the lid and the seal at first. When I open the jug, liquid that was clinging to the top of the lid then slides down to the inner ring and wets the threads. When I place the lid back on, the liquid that is now at the bottom of the threads, drips down the side of the jug. I have since found that I can flick most of the liquid out of the lid rim. This seems to work fine to keep any liquid from dripping down the sides.

Wrap-up:

Pros:

- keeps hot liquids hot even when not primed

- sized nicely to fit in water bottle slots on packs

- worked well with both hot and cold beverages

- plug seal lid can trap liquid causing it to drip when closed

- lid has to be tight to prevent leakage

This concludes my long term report on the Primus Lunch Jug. Thank you for following this test series and thanks to BGT and Primus for allowing me to play with this jug.

Reviews > Cook and Food Storage Gear > Utensils > Primus Lunch Jug > Test Report by Kathryn Doiron