Lab grade ethanol should be safe (particularly if made anhydrous with 3A molecular sieves); any trace impurities will be combusted, anyway.
However, as others have noted the flame is invisible and spills readily ignite. Gooey marshmallow will gunk up your stove, too, so if you decide to give it a try, probably best to use a small, disposable unlined pot/can (nothing lined with polymers).
If I may suggest an alternative:
Won't work indoors, but a little gassifier stove running on wood pellets is cheap, and even more green than ethanol as wood pellets are typically made from waste streams (ie. sawdust). They're most often used in smokers for brisket, ribs, etc.
They make smoke while lighting, but are remarkably efficient after a couple minutes. And wood pellets are dirt cheap (like $5-10 for a 20lb bag).
Took a hike at the beach and saw some dolphins while making coffee. Tried out the ZEN Camps Stand / Windscreen which looks pretty much like the Esbit pot stand/windscreen with some extras. Works great. Comes with a plate for using it with solid fuels too.
> Self heating coffee! Brilliant!
Yeah, I haven't ever seen these in the US, I've only seen videos of them online.
My main concern for self heating coffee cans for backpacking is it generates a lot of bulky trash to pack out, but... hang on, let me google something.
Well, would you look at that?
https://www.amazon.com/MRE-Flameless-Heater-Pack-12/dp/B00KI3MC6O
Apparently you can get those things without the whole MRE kit. Those things get hot enough to practically boil water and generate steam. I'm not sure how I would use them to make real coffee or if they would get hot enough for it. I guess I'd try to stick a camp stove or metal canteen in the pouch.
I'd also probably still use instant coffee, either Starbuck's Via packets or a good dark coffee like the Nescafe Classico or store brand variety of that. Less mess and stuff to pack and you don't need the gear like a pourover or aeropress or something.
They also generate some messy trash since the heater packs will be wet after use, but you could probably re-use a single heater bag for a while, or do something clever with a double-stacked mess kit pot like a double boiler.
It's probably safe to assume you don't want to directly drink any of the water in contact with the heater packs, so that's an additional water budget. But on the plus side you can probably use unfiltered water for the reaction as long as you don't get steam or condensation from it in your potables.
On the other hand I would also presume that they come in sealed packs or a reason and if you open them or expose them to humidity in the atmosphere it's going to start the reaction.
Oh the titanium tongs. I picked them up previously since they just looked useful. I originally picked them up for like flipping steaks. They aren't the strongest at picking up heavier items though. Still really useful.
I use them to pick up hot coals/wood, adjust the legs on the Nano, pick up my pot/pot lid, place the Trangia simmer ring, etc. Anything where I don't want burnt fingers. I think I still need stronger tongs to go along with it.
I put the link in the description of the video but here it is https://www.amazon.com/dp/B08HD4H6C8
Was looking at this martin propane stove. Kinda big actually for what i want, i just want the open flame, but i guess it would collect some of the grease. https://www.amazon.com/Martin-Portable-Outdoor-Single-Propane/dp/B07CZ28F2G
I'll attach a link to the one I borrowed, I'll put it at the bottom as it's a silly long Amazon link.
It was speedy, that bit was fine. Easy to put together and use etc. Came with a little grill rack to use with pots and pans and what not. I just didn't take to it, it wasn't quite as nice to watch or relax with as it burnt down. Like I couldn't imagine just kicking back, dropping the odd quartered stick in to it and enjoying the fire etc. Does that make any sense at all? Probably not.
Long link...
CANWAY Camping Stove, Wood Stove/Backpacking Stove
I’ve used this type of woodgas stove. Cheap, small. I usually keep a bag of wood pellets for it so I’m not looking for fuel, but would not be a problem feeding it broken twigs.
They can be a little finicky, and aren’t good for continuously adding fuel to.
/u/MyVirtualSoapbox I ordered it from Amazon, linked below. Ordered July 25 and arrived August 4.
https://smile.amazon.com/gp/product/B00TQKACS0/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1
I just bought a Lixada Ti twig burning stove from Amazon for like $18 as a backup for a hike I'm doing where isobutane fuel may not be available. It works OK, I guess. really sooted up my pot and was really fiddly with trying to keep twigs fed. Was also a pain to light, ended up having to use some cotton and vaseline firestarter. That might get better with practice.
If all you are looking for is a cheap stove, you probably won't find anything better than the BRS 3000 on Amazon for $17 . pair that up with the larger (but heavy) isobutane container sold at Walmart for under $10, and it will last you 30 nights or more. You pay the same for the stove, but the convenience of just being able to just light it up and start cooking is worth the extra ten bucks for the fuel.
Sorry...I copied the link to one without a bail. I think this was the one I meant: Lixada Titanium Camping Cup,Ultralight Portable Cup Hanging Pot with Lid and Foldable Handle for Outdoor Camping Hiking Backpacking(900/1600ML) https://www.amazon.com/dp/B07H99DK4D/ref=cm_sw_r_cp_api_i_-dv8DbDTHS54T —select the 900ml titanium pot