11/2/2004 - Intial Version 11/7/2004 - Update 11/20/2004 - Update 12/13/2004 - Update 12/14/2004 - Update 12/15/2004 - Update Notes on Alcohol Stove Burn Tests by Mike Martin: 1) These tests are not meant to be a head-to-head comparison of the stoves. Rather, I happen to have these stoves, use them for different purposes, and I'm trying to get the best performance out of each of them by tweaking variables. I was attempting to optimize pot, fuel, and windscreen configurations for each stove, not duplicate tests across the different stoves. 2) The performance of the Turbo F appears pretty similar to that of the Turbo IIF, so the IIF is used in most tests. 3) Four windscreens were used: a) 3.1x18.5" w/ holes .5" from bottom in 1" intervals. This screen has been used in configurations ranging from "breeze wall" to full enclosure w/ 0.5" gap around Titan Kettle. Also used in a 50-75% coverage setup w/ an Open Country 2L aluminum pot. b) 6" tall x 5.5-6" diameter w/ holes at .5" intervals along bottom edge -- used w/ Titan Kettle and Snowpeak 600 mug. c) 4.9" x 17" w/ two rows of holes at 1" intervals along bottom edge, wrapped to 5-5.5" diameter -- used w/ Snowpeak 600 mug. d) 6" tall x 7" diameter w/ holes at 1/3" intervals along bottom edge -- used w/ Open Country 2L pot. 4) In the unpressurized stoves, the fuel efficiency of Methanol was pretty similar to Ethanol in spite of its fewer BTU/lb. I attribute this to better flame control and shape with the Methanol. My goal is to improve the Ethanol burns to achieve even greater weight efficiency. 5) The Sunnyside and SLX denatured Ethanols burn similarly, but I prefer the SLX because its fumes are not as bad. 6) Adding a small amount of water to Ethanol fuel improves the flame shape and control in my tests on the Brasslite stoves. However, other users don't seem to have the flame spillage problems to the extent that I do. So, my experience may not be typical. 7) I had high hopes for the 99% Isopropyl Alcohol as a fuel. I had heard of the poor sooty flame with 70% alcohol and had hoped that the water content was causing this. Sadly, this doesn't seem to be the case. 8) Heat output (BTU/hr) calculations were based on the type and amount of fuel used and the total burn time only. Peak output values are likely higher because the low flames during startup and end of burn are averaged into the calculation. [Note: BTU/hr calculations also assume complete combustion of the fuel -- any uncombusted fuel (e.g. soot) will reduce the actual heat output.] 9) Estimated fuel usage is only a crude estimate. It assumes constant heat output and multiplies initial fuel times boil-time/burn-time. 10) Unless otherwise noted, all tests were conducted indoors at 68 degree air temp with 63-64 degree water temp, 2200ft elevation. 11) I attribute the relatively long boil times of the gas stovetop to the burner configuration which did not direct any flames toward the center of the pot bottom. 12) I attribute the very fast boil time of the Xponent Xtreme stove to both it's high heat output (14,000 BTU/hr claimed by manufacturer, 13200 measured), and to the burner configuration which directed almost all of the flames toward the bottom of the pot. 13) All of the unpressurized stoves were more sensitive to windscreen configuration than the Penny stoves for a couple of reasons: a) The pressurized jets are less suseptible to being blown around than the low-speed flames of the unpressurized stoves. b) The windscreen affects the temperature of the stove, and so affects the rate at which the fuel evaporates and burns. The penny regulator diminishes this effect by increasing the central flame if the stove starts to overheat. The central flame is located relatively far from the lip of the burner on the Penny stove, and so contributes less to heating the burner than the peripheral jets. c) The windscreen affects the amount of oxygen available to the burner, and thus the burn rate. Again, the Penny regulator offsets this effect if the stove gets too much oxygen. 14) The best way I've found for priming the Penny stove is to add approx. 5ml to the fuel cup, then fill over the penny. When the fuel boils, fuel above the penny will drain into the cup. This avoids wasting fuel with overpriming -- priming ends immediately after the fuel boils. 15) Most recent tests used Everclear (95% Ethanol). It burns with very little fumes, but a somewhat yellow flame with some soot deposits on the pot. The quality of the burn is certainly acceptable, if low odor and multi- use are important considerations. Otherwise, SLX provides a better burn for much less expense. The soot problem is more severe with the Penny stove than the unpressurized ones due to the more concentrated flames. 16) Fuel Observations to date: Heet (Yellow Bottle) -- 99% Methanol, burns beautifully with little odor or flareups. Readily available at gas stations and auto parts stores. But, with only approx. 9700 BTU/lb, not as weight efficient as other fuels. Sunnyside Denatured Alcohol (from Home Depot) -- Primarily Ethanol at around 12700 BTU/lb. Burns Ok, but fumes are bothersome to me. S-L-X Denatured Alcohol (also from HD) -- Also primarily Ethanol. Burns just like the Sunnyside stuff, but the fumes are not as bad IMO. Heet (Red Bottle) -- 99% Isopropanol, potentially over 14000 BTU/lb if you could get it to burn cleanly. But, burns with yellow flame and leaves sooty deposit on pots. Swan 99% Isopropyl Alcohol -- Burns just like the Red Heet. Typical rubbing alcohol smell. Everclear -- 95% Ethanol. Not available everywhere. Very Expensive. Soot problems are minor compared to Isopropanol. See note 15, above.