stainless steel mugs

[Martyn]

Just done my super scientific test just for you Adi...

Method:

I filled a bowl with about 2L of cold tap water. I used a gas stove with a full 250 cannister and left the valve set at the same throughout - I didn't notice the flame intensity change at all. I lit the stove and let it warm up for 1 minute - all done at kitchen ambient temperature. I used a measuring jug to measure all the water volumes. The Trek 700 has a lid which would improve it's performance, but I thought that gave it an unfair advantage in this test, so I tested it without the lid.

First up was the Trek 700 with 250mls of water from the bowl, it took 2 mins 20 seconds to reach a bouncing boil. I could lift the 700 off the stove with bare hands via it's handle and I was able to take it straight to my lips, it was hot but it didnt burn.

Next, the crusader with 250 mls of water. It took 2mins and 30 seconds to reach a bouncing boil. The handle was very cool, but the body was far too hot to take it straight to my lips.

Next the trek 700 with 500mls of water. It took 4 mins and 20 seconds to reach a bouncing boil, although the handle was very hot, I was still able to remove it from the stove with my bare hands (with care). I poured half the contents away and it was hot, but passed the lip test.

Next, the crusader with 500mls. It took 4 mins and 45 seconds to reach a bouncing boil. The handle was very cool to touch. I poured half away but there was no way in hell I was even going to attempt the lip test.

Summary, the Ti Trek 700 boils faster than the crusader, no question, accross various volumes. The body of the Trek stays cool enough to use it as a drinking mug straight from the stove, no way with the crusader, some cooling of the lip, or some cooling down time is needed. The handle of the trek wasnt brilliant, it got hot (but cooled quickly once off the stove). I was a little twitched about how precarious it was with 500mls of boiling water. Despite it's irregular shape, the crusader was more stable and I could handle it with greater confidence. As a cooking vessel, I would prefer the crusader for it's cool handle, and the weight of it makes it more stable on the stove. As a mug, the Trek is far better, cooler to the lips, a more familiar shape and slighly faster to boil.

For a mug, that you can cook in at a push, the trek wins for me. Stop, take your bergen off, pull out your trek package, add 200-300mls of water, put the lid on, light the stove, wait 2 & 1/2 minutes, add coffee and drink. Couldn't be lighter, simpler, cleaner or faster.

The crusader weighs 250 grams.
The Trek 700 weighs 90 grams (without lid).

This was done with a powerful gas burner with the valve opened wide up. I dont have a meths burner, but would be interested to know the results. If I have a couple of hours to spare one day, I might try it with a hexy stove (edit - I suppose this could be simulated with a gas burner, with the flams set to a super low level). But it should be noted, that the trek 700 is supposed to be a super lightweight, compact gas burner package. It's designed to accomodate 2x100 gas cans inside (or 1 gas can and stove) and a third can on top of the lid - it's not really a hexy solution.

 

[Martyn]

...but then I pulled up the data sheet for titanium that shows that it has a thermal conductivity that is ten times less than that of aluminium and about 15 times less than copper. This means that as a rough comparison a mug or pan made of Ti would need much more heat than one of the same thickness made of Al....

That would be for pure Titanium. These mugs are Titanium alloys, with Alu and other metals added. Alloys have very different thermal properties to pure metals.

 

[Adi007]

Very interesting Martyn - thanks for that! :biggthump

A lot depends on the Ti alloy used, although many of the alloys I've come across have poor thermal conductivity compared to Al and Cu ... but then again a gas burner puts out a lot energy. The bottom line must come down to the fact that they can make a thinner mug with Ti.

I wonder, do you have a black crusader mug of brushed metal as that would make a difference too.

 

[Martyn]

I wonder, do you have a black crusader mug of brushed metal as that would make a difference too.

Yeah, I've a teflon coated steel crusader - you want I should do some more tests?

 

[Adi007]

I wonder, do you have a black crusader mug of brushed metal as that would make a difference too.

Yeah, I've a teflon coated steel crusader - you want I should do some more tests?

No, don't worry about it. :-D I've got some Ti spoons so I might have a play later to see how fas the handles heat up when the ends are in boiling water.

I've got both types of mug and I've noticed that the black one cools quicker (because it emits better) than the brushed one ... equally it should warm up quicker.

 

[sargey]

the relatively poor conductivity of the Ti and s/steel is what makes 'em usable as cooking and drinking mugs, as martyn's tests show.

this lack of conductivity becomes a real problem when you're trying to cook foods with less water content, try simmering a pot of porridge for example. you'll find that even with a nice gentle simmer on top you'll have a good chance of burnt food in the bottom of the pot. i reckon your best lightweight bet would be to have a Ti mug, with hard anodised ally everything else. if you're not so worried about keeping the weight down, youcn get copper bottomed s/steel cooksets, i don't know if they're really significantly better. thicker kitchen pans spread the heat muchmore evenly than backpacking pots.

martyn, hexy blocks provide the lightest of all fuels. also the most expensive. what you really need is the multifuel trangia clone shown ready to go in my last pic.

cheers, and.

 

[Adi007]

what you really need is the multifuel trangia clone shown ready to go in my last pic.

cheers, and.

By multifuel, what fuels do you mean? Petrol? :bu:

 

[Martyn]

Well I did the test anyway and got some interesting results.

First, I cooked up the Trek 700 with 250mls, but this time put the lid on. It came to a rolling boil in almost exactly 2 mins, ...20 seconds quicker than before - but it should be noted, that the stove had been turned off, then on again, so I cant be sure the flame was set the same.

Then I tried the teflon crusader, 2 mins 10 secons, that was quicker too, maybe because it's black, maybe because the flame of the stove was different - I cant be sure.

Here's the interesting bit.

Next, I turned the flame of the stove down real low, about a low simmer. I put 200 mls of water in the trek and popped it on there. It took 6 mins 45 seconds to reach a bouncing boil.

Next up, the teflon crusader, 200 mls of water and whoa 5 mins 50 seconds, nearly a whole minute quicker than the trek.

I thought this was odd, so I repeated the trek test and got almost exactly the same as the first attept, less than 5 seconds different at 6 mins 40 something.

The crusader boils quicker on a lower heat - quite a bit quicker too!

I'm guessing this has something to do with the larger mass of the crusader, it stays hotter longer than the thin Ti mug, it probably keeps the heat in better, so aids cooking on a burner with low output. I'd bet the difference would be even more profound on a hexy stove.

It seems on a high energy burner, the thin Ti mug is better, but on a low energy burner, the greater mass, and therefore better insulation of the steel mug, works in it's favour.

I still felt the crusader was a better cooking pot, though that horrible teflon coating makes the water taste foul - it stinks too. I've washed & scrubbed it several times before, but just cant get the taste out of it.

I figure if meths/hexy is your bag, the crusader is a better bet, it's certainly a better cooking pot because of the handle design and stability from it's weight. But if gas is your thing, the Trek gets my vote. I suppose it all depends on how you like to do your thing.

 

[Adi007]

I'm guessing this has something to do with the larger mass of the crusader, it stays hotter longer than the thin Ti mug, it probably keeps the heat in better, so aids cooking on a burner with low output. I'd bet the difference would be even more profound on a hexy stove.

I'd hazard a guess that you are seeing this is because of the poorer thermal conductivity of Ti and TI alloys ... on a roaring burner it can supply enough energy to the Ti to pump the energy through the alloy into the water, but at the lower energy end much less is getting through the metal into the water, it is instead being dissipated by the surface metal. Given that a gas burner (even at a low heat) is far more directional than a hexy flame, I'd expect even poorer performance from Ti ...

 

[Martyn]

I'd hazard a guess that you are seeing this is because of the poorer thermal conductivity of Ti and TI alloys ... on a roaring burner it can supply enough energy to the Ti to pump the energy through the alloy into the water, but at the lower energy end much less is getting through the metal into the water, it is instead being dissipated by the surface metal. Given that a gas burner (even at a low heat) is far more directional than a hexy flame, I'd expect even poorer performance from Ti ...

Possibly so, but I think the mass has something to do with it also. When boiled ater is tipped out of both mugs, the Ti cools much faster than the crusader. If they were the same mass, the Ti would cool slower, with a poorer thermal conductivity. So the faster cool, must be due to it's extremely low mass & thin walls.

So let me get this right, on low energy burner, the thin walls (poor insulation) and poor conductivity of Ti, means that it takes more energy from the stove to heat the contents, as more of the energy is being lost to the environment.

However, on a high energy stove, the effects of poor conductivity of Ti are overcome, the thin walls of the pot now work in your favour to allow a faster heat transfer into the food.

I think Sargey is right, for a good all round option, a SS billy, with Ti mug is good.

But I have to say, if I was stuck in the middle of nowhere, with nothing but a few matches a knife and my choice of mug, I would opt for a crusader over a Ti mug every time. I suppose that would be the bushcraft way. But it's hard to ignore the convenience, weight saving, cleanliness and speed of s Ti/gas combo. For knocking up a quick brew while on the move, the latter is tons more convenient, if a little less "bushcraft".

 

[Adi007]

There's a simple test for thermal conductivity ... fill both with boiling water and test the surface temp of both mugs - the cooler the outside, lower the thermal conductivity (if you want to reduce on the effects of air conduction through the top, put some foil over the top). The heat trying to get into the mug will have as much trouble as the heat trying to escape.

I'm really intrigued now...

 

[Martyn]

There's a simple test for thermal conductivity ... fill both with boiling water and test the surface temp of both mugs - the cooler the outside, lower the thermal conductivity (if you want to reduce on the effects of air conduction through the top, put some foil over the top). The heat trying to get into the mug will have as much trouble as the heat trying to escape.

I'm really intrigued now...

Oh, without doubt, the Ti is cooler.


This stuff addles me brain. :-D

 

[Adi007]

There's a simple test for thermal conductivity ... fill both with boiling water and test the surface temp of both mugs - the cooler the outside, lower the thermal conductivity (if you want to reduce on the effects of air conduction through the top, put some foil over the top). The heat trying to get into the mug will have as much trouble as the heat trying to escape.

I'm really intrigued now...

Oh, without doubt, the Ti is cooler.


This stuff addles me brain. :-D

Me too!

I know you need about 4.2 Joules to raise the temp of 1g of water by 1 degree Centigrade (at standard temperature and pressure), that a Watt is 1 Joule per second and that a gas stove pumps out about 2500 - 3000 watts, this means that if you had an efficient system, you could boil 500 g (or 500 ml) or water in about a minute.

But beyond that I dunno either ...

... I'm off to have a cuppa!

 

[Martyn]

Me too!

I know you need about 4.2 Joules to raise the temp of 1g of water by 1 degree Centigrade (at standard temperature and pressure)!

Yeah, that'd be the specific heat capacity of water right? But what I cant work out, is what part is played by the pot?

Yeah brew time - I'm using my russel hobbs. :-D

 

[Martyn]

y'know this discussion is scarily familiar to one I had a while ago about the relative merits of heatsinks - that addled me brain too. :-D

 

[Adi007]

Maybe we should market a BCUK Ti heatsink!

 

[Martyn]

Maybe we should market a BCUK Ti heatsink!

Yeah, dont waste all that energy from your processor, insulate it with a Ti heatsink - just like insulating your loft saves energy. Hmmm, works for me.

 

[EdS]

The Ti mugs might take a bit lonnger to boil sometimes but how long does it take for s/steel to cool down enought to be drunk from.

Has anyone timed it from lighting stove to getting a warm drink down you?


If i want to keep a drink warm for a while I use an old Aladin insulated plastic mug with lid - it'll keep a brew warm for 20 minutes or so. It a bit bulky but light weight plus it has a a wide base so is difcult to know over even on uneven ground...

... except for inside a tent for some reason.

 

[jamesdevine]

I have an Aladin mug as well and they are bulky but if you are able to light fire and have a small can to heat the water they are not bad. The lid seals them tight so they make good storage for your brew kit as well.

Plus 20mins gives you plenty of time to set up camp while still having a hot cuppa to sip as you go. Keeps things cool as well.

I somtime us it on the train to work when I'm sometimes late (OK when I'm often late)

James

 

[al]

all i did was mention some cheep mugs from tescos and ended up with a science discussion :-D