Optimus Crux Review

Overview

The Optimus Crux is a foldable-burner canister stove built around one obsession: making itself disappear into your pack. Two features set it apart from most canister stoves: a folding stem that flips the burner down into a tiny overall package, and pot supports that extend up and outward from the burner, creating a compact and reasonably durable platform. At 83g (2.9 oz) with a 3000W output and a built-in piezo ignitor, it targets gram-counting fast-packers who still want water boiling in under four minutes.

Key Specs

Spec	Value
Weight	83 g (2.9 oz)
Packed Size	3.3 × 2.2 × 1.3 in
Power Output	3,000 W (10,200 BTU)
Boil Time (1L, calm)	~3 min
Fuel Type	Butane / Isobutane / Propane
Ignition	Piezo auto-ignitor
Burn Time (220g canister)	Up to 60 min at max output
Comparison	See how Crux compares to similar gear

Performance

Boil Speed

On paper — and mostly in practice — the Crux is fast. At 2.92 oz, it came in just 0.32 oz heavier than the lightest stove in Outdoor Gear Lab’s field test, and boiling a liter of water in just over three minutes made it the fastest small canister stove they reviewed. That tracks with the manufacturer’s 3-minute spec, which is more honest than a lot of stove marketing copy.

Wind: The Achilles Heel

Here’s where reality bites. In OGL’s wind test using a box fan producing constant 2–4 mph airflow, it took 7 minutes 54 seconds and 0.9 oz of fuel to boil 1 liter of water — nearly double the calm-air time. The wide burner head spreads heat more evenly than narrower jets, but the design trades some wind resistance for that broader flame pattern. Optimus sells a clip-on windscreen separately, and if you’re doing anything above treeline or in exposed terrain, you should treat it as required equipment rather than an optional accessory.

Simmer Control

Mixed reports here, though the consensus leans slightly negative. Simmer control is tricky — the control lever offers very fine adjustments, almost too fine, making it difficult to lock in exactly where you want it, and semi-constant micro-adjustment can be needed to hold a certain flame size. More critically, on occasion the flame goes out completely without warning when trying to simmer — worth knowing before you plan a gourmet backcountry meal. For boiling water and rehydrating freeze-dried food, it’s a non-issue. For actual cooking, keep your eyes on the burner.

That said, the wide burner head does reduce hotspots on titanium cookware, which is a real advantage over pinpoint-flame competitors like the MSR PocketRocket 2.

Stability

The stove still offers generous heat output and can boil water faster than its competitors, but the various folding mechanisms do take away from overall sturdiness when using tall pots or mugs.

It’s a little loose when “snapped” into position, which is the main downfall once a pot is placed on top — but bear in mind you buy this stove for its packability and light weight, so deal with the smaller pot arms and slight looseness.

Several users note it’s never actually caused a spill, but it will make you pay attention to setup.

Packability

This is where the Crux genuinely earns its name. An innovative folding burner head and a convenient strap-on protective stuff bag let it pack down to nothing and store in the empty base of a standard LP gas canister. Paired with a pot like Vargo’s BOT 700, it can form one of the lightest cooking systems you’ll ever carry.

Cold Weather

No pressure regulator here, which matters. The canister can freeze in extreme cold temperatures, so add a little extra insulation in your pack if camping in extreme conditions. Plan to keep the canister warm — inside your sleeping bag at night is the standard trick — and accept that output will drop as temperatures fall. Below freezing, this stove is functional but noticeably sluggish; it’s not the right tool for winter mountaineering.

Build Quality

The burner oxidizes after the first use, turning from shiny factory black to crimson rust — purely aesthetic, but it’s a cosmetic blemish that doesn’t happen to the PocketRocket or similar competitors.

Structurally, multiple long-term owners report it holding up reliably across seasons of use.

Pros & Cons

Pros

• Exceptional packability — folds into the base of a gas canister
• Strong 3000W output for its weight class; among the fastest boil times in the category
• Built-in piezo ignitor saves carrying a separate lighter (though pack one anyway)
• Wide burner head distributes heat evenly, reducing hotspot risk on titanium cookware
• Comes with a stuff sack; simple setup in seconds

Cons

• No wind resistance — boil times and fuel consumption roughly double in even light breeze; a windscreen is effectively mandatory
• Folding hinge introduces a slight wobble that can feel unsteady under taller pots
• Simmering at very low flame is finicky; flame can extinguish without warning
• Burner oxidizes to a rusty color after first use (cosmetic only, but noticeable)
• No pressure regulator means noticeably reduced performance in cold temperatures

Who Should Buy This

The Crux is the right call for solo fast-packers and ultralight-minded backpackers doing three-season trips in below-treeline terrain. It’s best for fast and light backpacking at elevations under 12,000 feet. If your cooking routine is mostly boiling water for coffee and rehydrating dinner pouches, this stove checks every box. If you regularly camp in exposed, windy conditions, plan to do actual cooking, or head out in winter, look elsewhere — consider the MSR PocketRocket Deluxe for better simmer control, or a wind-integrated system like the MSR Windburner for serious all-weather use.

The Crux Lite — the non-folding sibling — shaves 11g and drops the piezo ignitor, but loses the folding party trick. The Crux lineup consists of two models: the Crux and Crux Lite, with no huge performance differences beyond the folding mechanism being eliminated and 11g saved on the Lite. If the nesting-in-the-canister feature isn’t a priority for your kit, the Lite is worth considering.

Verdict

The Optimus Crux is genuinely excellent at one thing: disappearing into your pack while still delivering fast boil times. The folding burner head is a clever design that earns its small weight penalty over the Lite version, and the piezo ignitor is a convenience worth having. What it isn’t is an all-conditions workhorse — wind exposure and cold temperatures reveal its limits quickly. Use it in calm, three-season conditions with a windscreen handy, and it’s a hard stove to beat at this weight. Push it outside that envelope and you’ll be frustrated.

Rating: 7.5 / 10