Sunday, 3 July 2016

Review: Trangia UL HA 27-7 Cookset with Gas Burner

The Trangia 27 Series Stormcooker is a smaller version of the 25 Series. The Trangia 27 system is suitable to cook for 1 or 2 at a time. In Scandinavia it is called the "StormCooker" for its reputation to keep working in poor weather conditions.

Many lightweight stove systems are unstable, wind-prone and reduced to boiling water only, even adjusting fuel flow for simmering may be difficult.  The Trangia system is stable, wind-protected and well known for it's cuisine versatility, enabling bacon/eggs, naan bread, risotto, pasta, pancakes and pizza. 

What You Get
The out-of-the-box Trangia 27-7 UL HA (the ultra light, hard anodised version) cookset weighs 720g with the methylated spirit burner.  The kit includes stove base, integrated windshield, 2 nesting 1 litre pots, frypan/lid, pot gripper and strap along with the methylated spirits burner with its lid and simmer ring. The two 1 litre pots and the pan/lid are anodised. The 2 nested pots look identical in size and nest very closely. There is room inside the packed windshield to fit a third pot if Trangia ever manufactured a slightly larger version. No kettle is supplied, but Trangia have one you can fit inside the nested pots (and in a miracle of design also fit the metho or gas burner inside).

Another option Trangia offers is a Multi-fuel Burner.  This has a 0.32mm jet for canister gas and Shellite/kerosene use.  The Primus Omnifuel has a similar looking fuel system but there may be differences in connectors.

Trangia 27 nested pots with a small firesteel. A metho or gas burner or 220g gas canister can also fit inside.
 This review mainly looks at the Trangia Gas Burner with this cookset. I purchased this 180g Gas Burner from a local shop but I understand it is now unavailable as there is an issue with Australian standards compliance. This compliance is expensive to obtain and the market here for these devices is small.  I understand the Trangia gas burner complies with the prEN 521 (EU and Nordic) and CAN-11.2-M79 (Canada/US) standards.  The burner is robust with pre-heater tube and has good simmer control.

Trangia Gas Burner product sheet snippet

Gas consumption indicates about 88 minutes of heating from a 220g canister. That's about 17 minutes per day for a 5 day trip.  Over 5 days my usage is around 220g but I seem to manage about 3 1/2 1L boil ups per day by using a low gas flow rate to do my heating.

Two Trangia 27 Systems

System 1  I added an 18cm 73g Multi-disc (lid/strainer/cutting board), 10g of 3mm CCF pot and pan cosies and a MYOG foil pot lid for a cook system weight of 803g. A full 500ml (400g methylated spirits fuel, gross 516g) Trangia fuel bottle brings the total to 1,319g.  You can also store 70g of methylated spirits fuel in the stove which is enough to boil 2L with some left over. Add an ignition source. You can pack everything into the nested Trangia 27 system except the fuel bottle.
Trangia 27 secured for packing.

Under backyard testing, the Trangia 27 cookset plus spirit burner used 18g of methylated spirits and took 11 minutes to boil 1 litre of water.  That comes to about 22 boils for the 500ml Trangia fuel bottle.  Getting 20 boil-ups would be a good result and with 2 boil-ups per day, it may last up to 9 or 10 days.
Trangia 27 multidisc lid/strainer/cutting board. Great for cutting cheese and stras.
I reckon the multi-disc is worth getting as a cutting board, cheese board and pot lid. I don't use the strainer as I use the minimum water method.

System 2  For the Trangia 27 cookset plus gas burner subtract the 113g methylated spirits burner and 516g full fuel bottle and replace these with the Trangia Gas burner at 183g and a 363g gas canister. That comes to a slightly lighter 1,246g cook system with 2 pots, fry pan and enough fuel for 5 days at 2 to 3 1L boils per day (see stove test below).
The Trangia Gas burner is strong, tough and very well made. A great cooking engine.
You can store everything inside the nested Trangia 27 cookset except either the gas burner or a 363g (220g net) gas canister.  One of these items will need to be stowed separately.

The gas burner has a 37mm jet.

The Trangia Gas burner installed on Trangia 27 base.
The burner snap-mounts in to the base. It is hard to see in the photo, but I rounded over pointy right-angle corners on the burner spring mount with a file.

The Trangia 27 cookset plus Gas Burner combo forms a remote canister stove system.  Since the burner has a pre-heater tube (which can get red hot), the canister may be deployed upside down which makes for better performance in sub-zero conditions. This is a must-have feature for snow and alpine adventures.

A Comparison with 2 Primus Omnifuel Systems

The Primus Omnifuel is a very good liquid fuel stove which I have used on snow camps with great success.

The Trangia 27 plus gas burner at 1,246g  is nearly 180g lighter than a Primus Omnifuel in Shellite mode with a 2 Ti wide-pot system like the Snowpeak Multi-Compact set. This Shellite system tested at 15 minutes for a 1L boil using 15g of Shellite fuel and weighs 1,424g with a 514g full (400g fuel) Shellite fuel bottle for about 25 boil ups.  The fuel efficiency difference is probably due to the better windshield on the Trangia.

The Trangia 27 plus gas burner is 100g heaver than the Primus Omnifuel in gas mode with the same 2 Snowpeak Multi-Compact Ti pots. This system tested at 11 minutes for a 1L boil using 18g of gas and weighs 1145g with a full 220g net gas canister for about 12 boil ups.  So the Trangia 27 gives better fuel efficiency assisted by a more effective windshield for that extra weight.

Stove Boil Test Result

So how long and how much fuel does it take to boil water on the Trangia? Trangia says the Gas Burner is high efficiency. When I tested the Trangia 27-7 gas burner using cold water from the tap and at about 18C ambient temperature using isobutane gas and using an initial low flow gas rate, aiming for a "minimum gas usage".  I used the frypan as a lid and resisted the temptation to lift and inspect, paying very close attention to the heating process, making occasional incremental adjustments as the heating progressed so that by the time the water boils I increased the initial gas flow rate twice going from about 20% to 50% rate. The reason I increase the gas rate as it gets closer to boiling temperature is because the pot and surrounding kit is losing heat faster to the ambient environment. This is more attention than when in the field since I have multiple other tasks that require attention. Using more gas early just wastes heat moving up the sides of the pot and away so I never use full throttle on any gas stove. I was astonished to find it did a 5 minute boil of 1L and used just 8g of gas in the process. That is fast and efficient.  At single figure significance, that makes a usage rate of  96g/h, well under the maximum rating of 150g/h for the stove and would give you about 2hrs 20 minutes burn time for a 220g net canister.  I've done a few stove tests now and that beats anything else I have done.  A second test of the Trangia 27 gas stove on the next evening took 7 minutes and used 11g of gas which is closer to field rates. Now in the field you may have ambient temperatures closer to 0 in the morning and also colder water. This will affect the time to boil and amount of gas used.

This stove combination is a winner for gas fuel efficiency.  If that efficiency is sustained you can do 28 1L boils per 220g canister. In the field with temps about 0-15C I get about three 1L boils per day over five days on one 220g gas canister.  It makes hot water for breakfast, tea, soups and noodles in this regime. Just dehydrated meals and I use the longer pot-cosy method with 2 small heatups, one at beginning and one at end.  A colder morning may use extra gas and a couple of times on a trip I get distracted with chores only to discover the boil has been achieved quicker than expected, so I take a spare 100g canister on 5 day trips.  It has been needed about 1/2 the time.  For 3 day winter snow trips I use just over 1/2 a canister but these have been supplemented with hut wood stoves for melting snow and some extra evening tea brews. 

I can usually get 10 and a bit boils from a Kovea Supalite minimalist upright gas stove and canister with a custom windshield. I use a circular aluminium reflector to stop the canister from overheating and keep a close watch on overheating by touching the canister from time to time. Too hot to touch is too hot! At 2 and a bit boil-ups a day that does for 5 days. 

One of the few negative features with the Trangia stove is you cannot see the flame while the pot is in place. So either lift the pot or go by sound when adjusting the flame. Suggestion to Trangia: The +/- markings on the black gas control nob could be painted white and I wonder if future gas regulators might possibly have a small dial gauge.This could be a simple fixed marked ring.

On a field trip at 1,700m this system prepared dinner and breakfast for two. A bit less than 2L was boiled at dinner plus a few minutes of simmering. About 1 1/2 litres of water was boiled at breakfast. I used a low heat setting and a total of 38g of gas was used.  This works out at a very low 11g of gas per 1L boil or 20 1L boil ups from a canister. That is pretty awesome.

So the evidence is that Trangia's claim of high efficiency is no marketing hype but fact.

Do Aussie bushwalkers need an inverted canister gas stove? In the snow, yes, but you may get by if you use huts or procedures to keep the canister warm. However it also gets sub-zero overnight in alpine areas in summer and is needed then!

Low Temperature Function

The gas burner has a pre-heater loop and can be used in "inverted canister mode" for below 0C conditions which occurs at altitude (above 1000m) throughout winter in mainland Australia and less frequently in summer.  Below 0C the Isobutane component won't evaporate, it has no vapour pressure, so only the propane component is gasified (down to -40C) pressurising the canister, exiting and is burnt off.  Unfortunately, this constituent of the gas mix is only about 20-30% of the gas in the canister and once this is burnt the residual liquid isobutane will just sit there with no vapour pressure to expel it from the canister.  So it is necessary in below 0C conditions to invert the canister before this happens.  The vapour pressure formed by the propane gasifying then pushes out the mixed liquified gases, heating it via the pre-heater loop to expand and gasify when it passes through the jet and then igniting. In this way, the propane proportion of the contents remains constant and enables the complete exhaustion of the canister by providing pressure at sub-zero temperatures above -40C.

Start the stove with the canister upright, then dial down the flow before inverting the canister. Some gas continues to flow from the pipe after the gas is turned off, so to avoid waste turn off just before your water boils/snow melts/food is heated.

I have operated an upright gas stove using isobutane at -2C to 0C on a couple of occasions and found it was reluctant and sluggish, using about twice as much gas over a much longer time to achieve a boil.
Trangia 27 windshield and gas canister attached.
Ready to be boiled for testing.

How cold does it get in Australia?

In mainland Australia it is unusual to get temperature reports below -10C.  Major caveats apply here and unusual does not mean never. The national lowest temperature record  was -23C in 1994 at Charlotte's Pass, Kosciuszko National Park (KNP).  A temperature of -19.6C was recorded there in 2010 and in August 2016 -10.4C was reached at Thredbo.  This was the only reported sub -10C minimum reading for all of Australia over that year. However note there are many very cold camping locations that are not reported, such as frost hollows under clear skies, wind chill effects etc.

The record low in Tasmania is -13C in 1983.  The record low in Victoria (Falls Creek) is -11.7C in 1970.  It was also -10.5C again at Falls Creek back in 1974.  The Queensland record low is -10.6C in 1965.  All the sub -10C record lows are older than 20 years.  There are no records of sub -10C temperatures in WA, SA or NT although desert nights can be very frosty and sub-zero.  While the record minimums gives us an idea of low end temperature patterns, it does not mean minimums have not reached below -10C in recent times.

So what about the monthly minimums for the last few years? For 2015 I found 9 reports of sub -10C minimums (Jun-Aug), mostly in KNP and a couple in Tasmania.  2014 had 10 reported sub -10C minimums (Jul-Aug), again mostly KNP.  2013 had 6 reports. Typically these temperatures were just below -10C to -13C. Some readings were for the same day from nearby stations. We can say it is not unusual that in any year that the KNP region will report a sub -10C minimum temperature on at least 1 occasion, but it is also fair to say that for any random day of the year that somewhere in Australia reports a sub -10C minimum is unusual.  There were no Victorian sub -10C readings (which we may expect from Hotham or Falls Creek) for any of the years 2013 - 2016.

It is also worth noting sub-zero temperatures (around -4C) in KNP in December is not unusual, so pre-heater gas stoves are not just for snow camping in winter.

Using a striker and flint to light the burner inside the windshield can result in a small whoomp-style explosive ignition, so avoid placing hands inside to ignite. I suggest removing the windshield to light or else use long matches - which can be found with BBQ supplies in shops. A long piezo igniter might work but I don't trust their reliability to work in all conditions.

The Trangia frypan should be used as a lid. There is high heat efficiency here.

The Trangia 27 with Gas Burner delivers very good efficiency as well as outstanding cooking versatility. Weight difference is also not significant with other remote canister stove systems which usually have ad-hoc windshields that require constant attention. Upright canister stove systems may be lighter but are even more unstable and frequently tip over with boiling contents and should never be used without stabilising canister legs or mounted and fixed to a piece of board.  The Trangia 27 could be set up within reach just outside your tent vestibule in a persistent rainstorm and be accessible, stable, functioning and safer than if it was in the vestibule.

The Trangia 27 with Gas Burner is an excellent solo combo kit for snow camps and high wind-exposed camping and hard to see what could beat it for a 2-person stove system in or out of snow.  The Trangia Gas Burner is unavailable in Australia so you will need to purchase it from an overseas supplier. In my view this is worth the extra effort as it is such a good performer. It could well end up cheaper than purchasing from a putative local supplier since we seem to have an "Australia tax" on overseas items (in addition to, and not to be confused with, the good old GST)

It is a bit more bulky and heavier than single pot upright canister stove solutions but is more versatile, much more stable and safer, especially for inexperienced bushwalkers,  and has become my go to cook kit.  

The Trangia 27 with gas burner gets the Bushwalkinglight 5 stars ***** award for product excellence.

I bought the Trangia burner and pots with my own funds and I have no relationship with Trangia.

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