View Full Version : Cobalt vs RUCAS

08-28-2012, 01:10
Recently, in a top section "cooking and food" thread,....http://www.whiteblaze.net/forum/showthread.php?86862-Which-stove
I had enthusiastically recommended the RUCAS alcohol stove.

zelph responded and offered to send me one of his Cobalt stoves for comparison,.....for free, I might add.
As promised, he delivered. The stove arrived last week as I was preparing to leave on an out-of-town business trip. I just returned today and had my first chance to test the two stoves in a head-to-head match-up.

My initial impression is that the Cobalt is also a very nice stove and I would have no problem recommending it as I have the RUCAS in the past. As to which is the "best", that's subjective. Each has it's own pros and cons. Either one could be preferred depending on scenario or personal cooking style.
For the gram weenie type, the Cobalt seems to be most fuel efficient, getting small jobs done with slightly less fuel. For boiling larger pots the RUCAS gets the nod as it burns MUCH hotter. Of course that means it's burning through more fuel,...and faster. The RUCAS is also slightly larger and would be more stable with bigger pots.


zelph sent the Cobalt stove with a wind screen included, as well as a little plastic measuring cup. The RUCAS comes with a Vargo fuel bottle included.



I conducted two initial tests. One, simply to test unassisted prime, or the time it takes to get a full 'bloom'.
The Cobalt won this test hands down. It had a full bloom in 15 seconds! Another thing I liked about the Cobalt was the metal wick. It made lighting easy.
The RUCAS took almost a full minute, unassisted. However, when a pot is hovered over to help pressurize the system, full bloom was cut to about 45 seconds.
Once lit, I let them burn uncovered until they burned out,.....and timed the burn. This part of the test is, in a way irrelevant as the fuel is burning wide open in the center well. When covered with a pot the center well would be smothered and flame would only be coming from the jets.
It was obvious that the RUCAS was burning much hotter, and that means it was also burning more fuel, and faster. This test was done with 1 oz of fuel in each stove, measured with the measuring cup supplied with the Cobalt.
The RUCAS burned out in 3:41. It happened quickly. One second it was roaring and the next it was out cold.
The Cobalt died down to a flicker at 4:15 and went out completely at 4:36


The second test was to see how long it took to get a rolling boil in an Evernew Ti 900 pot, filled to the rim with cold water from the tap.
I did not check temperature with thermometer.
I measured 1.5 oz of fuel in each stove.




When it comes to boiling a pot of water, the RUCAS wins. It's just obviously hotter.
I'm not sure if the alternating different size jets have anything to do with it or not, but it does put out more flame and heat.
I first noticed bubbles forming on the bottom of the pot with the RUCAS at 4:15 as opposed to 5:18 with the Cobalt.
The hissing sound of a simmer came at 6:12 with the RUCAS and 8:41 with the Cobalt.
A full rolling boil at 7:50 with the RUCAS and 9:04 with the Cobalt.

The Cobalt once again had a brief die down with diminished flame at 11:00 and went out completely at 11:40.
The RUCAS was at full roar until 10:23 when it died all at once.

Bottom line: I would primarily use alcohol stoves for boiling a pot of water for coffee. I'm usually making coffee for two, and I usually use the Evernew Ti 1.3 pot. For this purpose, the RUCAS would get my morning coffee quicker.
Those who only boil a cup or two to pour in a bag or make instant oatmeal will save fractions of ounces in fuel with the Cobalt.
Either one will get the job done.

FWIW,.....For actual cooking, I prefer real, fresh food. I can't stand packaged stuff like Mountain House!
I'll simmer dried beans that have been soaking all day for an hour or more, add cut up potatoes, carrots, garlic, mushrooms, celery, etc.
For this type cooking, it makes more sense to set my pot on a Purcell Trench grill situated on the campfire.

Second choice is the Emberlit UL. http://www.emberlit.com/
When boiling, then simmering for 20 minutes,.....such as rice and pasta dishes,.....the Emberlit is the way to go.

I like to pack light, but not at the expense of comfort. I usually take all three: grill, alchy, and Emberlit. ;)

08-28-2012, 12:45
Good report, thanks.

08-30-2012, 19:40
If you look at the 'bloom' on both stoves it's easy to see WHY the same amount of fuel lasts longer with the Cobalt and WHY the RUCAS burns hotter.
The Cobalt has 16 jets. The RUCAS has 32 jets. The jets on the RUCAS are of two different sizes, alternating smaller and larger.

I'll bet that zelph COULD, if asked,....or if he wanted to,......duplicate the pattern. ;)

I'm proud to have both stoves. For the type camping I generally do, boiling water for two people in the Evernew Ti 1.3 I'll continue to use the RUCAS. When I head out on a solo thru hike I'll take a smaller pot and pack the Cobalt.

09-23-2012, 20:59
WoW! excellent report. Lot's off good comparisons of the two stoves.

At the time the Cobalt was designed most folks were looking for the lighter weight, small diameter pots. It's good you point out that the RUCAS is better for larger diameter pots.

Lots of things have changed since. Titanium products are hot items on gear lists. Aluminum transfers heat much better than Ti. and yet it seems the majority are going for the Ti. and are really not concerned about fuel usage.

If I were to have the same hole pattern as the RUCAS it would certainly burn hotter.

This last batch of Cobalts that I made may be the last of them. I may "Retire" the design. Cabaggehead said I could copy his design so I may take him up on the offer. It takes a lot less time to make a bottle stove than the cobalt. Same with the RUCAS, lots less time to make.

Thank you for doing such a nice job on the stove comparisons.