Reviews > Cook and Food Storage Gear > Stoves > Primus EtaExpress > Test Report by David Bradish

PRIMUS ETAEXPRESS
TEST SERIES BY DAVID BRADISH
LONG-TERM REPORT
August 19, 2008

CLICK HERE TO SKIP TO THE FIELD REPORT
CLICK HERE TO SKIP TO THE LONG-TERM REPORT

TESTER INFORMATION

I started hiking in my teens in Arizona and New Mexico, primarily focusing on winter hiking. Since 1991 I have hiked a lot with my brother-in-law Ray mostly in California's Sierra Nevada range, and the southern mountains. In winter I bring as much gear as necessary to be safe and comfortable. For 3-season hiking I try to follow the principles of ultra light.

INITIAL REPORT

PRODUCT INFORMATION & SPECIFICATIONS

INITIAL IMPRESSIONS

The Primus EtaExpress is a light weight compact cooking system made for weight and space conscious backpackers.

It came to me in the retail box containing all the pieces seen above along with a manual for just the stove itself printed in eleven languages. It was actually more than I expected viewing the website. The stove puts out a claimed 8900 BTU heat output and a boil time of 2 1/2 minutes although they do not say how much water is supposed to boil in that amount of time.

The stove seems to be constructed completely from stainless steel except for the black plastic around the fuel valve. It screws onto a standard mixed gas canister and has two wings that stop it from being screwed down too hard by hitting the lip on the canister.

They sent a black piece of material with the Primus name on it that I think is a pot holder and is meant to protect the inside of the pot from being scratched up by the windscreen and fuel can. While thinking that I would replace it with a hiking washcloth I decided to run it under water. While not as good as my PackTowel it seems like it will work as one.

The stove lights on the first flick of the piezo electric igniter lever and shoots a blow torch-like flame far into the air. I guess that this hits the pot and flows outward to the heat exchanger. It makes sense that it should work as we use a heat exchanger that attaches to the side of a pot when we melt snow on winter backpacking trips.

I decided to see if Primus's claim of 2-1/2 minutes was for real. Since they did not say what amount they use I started with 2 cups/0.47 l of tap water at our office which is about 80'/24 m above sea level. I used this amount as this is what it takes to do most of my freeze dried meals. I turned the flame up high to give them the benefit of the doubt. I was very surprised to see it boiling in 60 seconds with rolling boil in 68 seconds. Next I cooled the pot back down and ran water in it to make sure there was no residual heat. I then filled it with exactly 1 liter/33.8 oz of cold water and fired the EtaExpress up again. I had boiling starting at 2 minutes 25 seconds and full rolling boil at 2 minutes 55 seconds. I was blown away.

I used a gram scale to weigh the canister for each use and got the following numbers. For the 2 cups/0.47 l boil it took 5 g/0.18 oz weight of fuel. The 1 liter/33.8 oz boil took 12 g/0.42 oz of fuel. This is a 50% plus reduction to what we have tracked with three other stoves over the past few years. Ray keeps records of this stuff and he tells me our norm for a 2 cups/0.47 is a third of an ounce or 9.4 grams. My test of a stove last year jives with that. I am very impressed with this.

One thing that worries me is the useful temperature range given of "above 41 F/5 C". In the mountains I am often around freezing even in the summer, especially in the mornings. I have used a lot of other stoves without problems so will watch this with interest.

FIELD REPORT

FIELD LOCATIONS AND CONDITIONS

I used the EtaExpress on a 30 mile/48 km backpack in the San Bernardino Wilderness where I camped at an elevation of 4300'/1311 m on sand next to Mission Creek. The temperature was 75 F/24 C when we stopped and got down to only 60 F/16 C by my thermometer. It was used to boil water for two dinners.

I also used it for one night at a campground by Silverwood Lake that was the starting point of a 41 mile/66 km dayhike the next day. It was at 3400'/1036 m elevation in temperatures that got down to 45 F/7 C and had a lot of wind. It was used to boil water for two dinners.

I took it with me on a solo two night trip to Domeland Wilderness to look for spots for a family vacation later this summer. I used it to boil water for two dinners, two breakfasts and one drink. Elevation at camp was 5700'/1740 m and the temperature got down to 39 F/4 C.

PERFORMANCE IN THE FIELD

I have been very impressed with the EtaExpress. It boils water faster than anything I have ever used including three 4 season stoves known for their high output jet engine burners. And I have to think it is because of the built in heat exchanger. Boiling water for just one cup of coffee happens in about 30 seconds.

I tracked the fuel usage for two of the trips. I started at a weight of 10 oz/283 g before two trips that saw 7 boils averaging 16 oz/0.5 L per boil. The total weight of the fuel used was 1.3 oz/36.8 g giving it an average of 0.185 oz/5.24 g of fuel used per boil. The last stove I tested I thought did very well averaging 0.35/9.9 g per boil. The EtaExpress is almost half of that. On a long trip this means being able to take a small canister instead of a big one. That is just another plus to me.

I was surprised at how poorly it worked in the winds at Silverwood Lake. I turned the wind screen into the wind but the stove kept blowing out. We had to use our bodies to help block the wind to keep it burning. Once blocked the EtaExpress had the water boiling in well under two minutes.

I have not had any reason to use the frying pan function of the lid so keep the handle folded in the Lid Lifter mode. I like the way that it does not get hot and is very easy to pick up. Here is a picture at Mission Creek.

LONG-TERM REPORT

LONG-TERM TEST LOCATIONS AND CONDITIONS

I used the EtaExpress on an overnight backpacking trip with 5 people at Round Valley in San Jacinto State Park. We were camped at 9160'/2790 m elevation. The temperature only got down to 55 F/13 C.

I used it on an overnight trip to Little Round Valley where we camped at an elevation of 9850'/3000 m. The temperature was over 80 F/27 C and never got below 60 F/16 C.

I used it on an overnight trip with my oldest daughter and her boyfriend for his first backpacking trip. We stayed at Tamarack Valley in San Jacinto State Park. We were camped at 9200'/2800 m elevation. The temperature only got down to 59 F/15 C this time.

PERFORMANCE IN THE FIELD

The trip mentioned above ended up being 5 people. I used the EtaExpress for everybody's cooking needs. I boiled water for 4 freeze dried dinners and three sets of oatmeal the next morning. The speed of boiling made it to where we did not even care that we had only one stove. At just over a minute per boil the EtaExpress was boiling just about as fast as we could get the packages open and ready. For the approximately 12 cups/2.84 L of water I boiled, it took 1.1 oz/31.2 g of fuel. Again this averaged out at 0.2 oz/5.7 g of fuel per boil.

This rate of consumption gives me 40 boils per standard fuel canister. I just bought some half-size canisters just to use in the future with the EtaExpress as a 4 oz/113 g canister will last me and Ray for a week long hike easily. My next use will be an 80 mile/129 km trip in Yosemite that I will take the small canister to use with it.

The only problem I have with the EtaExpress is the peizo electric lighter. It does not work very well above 8000'/2440 m. I had to use a lighter every time.

I got one scratch on the pot inside but other than that have had nothing wrong with the durability of it. And that was my fault for not using the stuff sack for the burner to save weight.

I would really like to have some sort of measurement marks on the pot. I will add some to the outside once the test is done, but some permanent marks inside the pot would be much better. Also I would not mind seeing a regular flat lid with a small loop handle as opposed to the frying pan with folding handle. This would save weight for me since I can't think what I would ever try to cook in so small a pan.

Other than that I have nothing but praise for the EtaExpress. While it is a bit heavier than my lightest cooking set-up the speed of boiling and low fuel consumption make up for it enough to keep me using it from now on. This is the best thing I have ever tested. My thanks to Primus and backpackgeartest.org for letting me use this great stove.

Likes

Very fast
Light weight
Compact
Great fuel consumption

Dislikes

Peizo electric lighter not reliable at high altitude
Needs measuring marks

Reviews > Cook and Food Storage Gear > Stoves > Primus EtaExpress > Test Report by David Bradish