What is the most efficient alcohol stove/system?

I find a cozy adds significantly to the efficiency.  For rehydrating a dinner, I’ve been able to bring 12 oz of water (+dinner) to a boil in about 5 minutes with 1 tablespoon + 1 teaspoon of alcohol with my fancy feast stove.  As soon as it’s boiling, I put the pot in the cozy for 45-60 minutes to finish rehydrating.  Even after 45 minutes when I remove the cozy, the the bottom of the pot is still so hot I can barely hold it in my hand.  I made this cozy from an insulated shopping bag I got at the grocery story for $3 (plus blue foam for top and bottom).

The Caldera Cone, with a wide pot and Zelph modified Starlyte stove seems like one of the most efficient boilers.  You can probably get slightly more efficiency by throttling back the burn hole a little for slower burning, but the standard cone, wide pot, Zelph stove combo is pretty darn good.  You’ll find plenty of other threads on this issue.

+1 Caldera Cone – specifically the Ti-Tri Sidewinder.  I have one for a 1.3L Evernew pot, which is great for 2 people and you can cook in the pot if you want.  Our favorite is ramen with add-ins.    You can get one for a smaller pot if you are going solo or just want a smaller/lighter pot.

I believe Shawn Forry and Justin Lichter used this on their Winter PCT thru hike a few years ago.  Not sure how often they used Alcohol.  You can use wood or esbit with the same setup.

+2 Caldera Cone

Yup, The caldera cone is, perhaps, the easiest, least fiddly package for alcohol. With some addons (zelphs burner, some insulation on the lid and around the cone) it is about as efficient as you can get. There are some that will give you slightly better efficiency, but you pay in fiddling. For example a lighter wind screen and a separate stand will give you slight improvements in fuel efficiency, but the weight of the stand offsets the lighter wind screen.

Alcohol all burns about the same. It is “partially combusted” (already mixed with “OH”) so it takes little to burn it cleanly. However there is a relatively large difference in fuels. Yellow HEET (methanol or methyl alcohol) has less specific heat than ethyl alcohol. Denatured alcohol is often a blend of the two (as long as it is clean burning stove fuel.) Methanol has about 9500BTU and ethanol has about 12800 BTU when burned…a BIG difference (around 25-30%.) Esbit is about 13000-14000BTU, Butane is around 21000BTU and WG is about 20500BTU. (Butane is a pressurized gas, though and requires about 50% of its weight in a pressure vessel or canister reducing it’s fuel value to about the same as esbit.) Wood varies a lot, but you really don’t care when you can just pick it up off the ground. ‘Corse, in some places, alky, esbit, and wood are still not allowed…anything that cannot be shut off immediately.

The longer you go out for, the better the high BTU fuels look. For example, It takes about two to three weeks at my usage for WG to pay. It takes about 5-10 days for canisters to pay. For just a few days out, alky or esbit is fine.

For two people in a group, you need to about double the fuel consumption. but you might find that small pots don’t work. This is a problem with the Caldera set-ups. You need to buy the correct size for the purpose you intend. I use a 1 qt pot almost all the time, solo or with a partner. It fits into my cone, or I can use it without. If I go with three people, I need my 1.7qt pot. It does NOT fit into the cone, and, if it did it would take a lot of fuel and a lot of time.