After finally getting out there this year, i tried my beer can esbit and found it to be a dud, lukewarm supper , blah. My old set up W/Ti pot + Msr wind screen always worked fine, boil 8 min.
So what was wrong? The can has a smaller bottom than the pot so the flames lick up the sides AND in this case blew out the vent holes in the bottom as the windscreen was to close to the can. Solution? raise the pot to Esbit distance 2.75 '' instead of 1.75. More [lots] space between pot windscreen, + add more windscreen on top. One vent hole at bottom , so screen is bombproof. Still just 85 gms all in.