While I'm not really into solid fuel, I thought it would be fun to compare 3 of the top solid fuel tablets for total burn time: Esbit, WetFire Tinder, and Trioxane. Here are the results:
Esbit was the clear winner while the Trioxane didn't even burn for a full 5 minutes (certainly not enough to boil 2 cups of water). Also, the Trioxane burned in a very uncontrolled flame pattern that would make it difficult to cook with. The WetFire Tinder did better but with an orange flame and shorter burn time than the Esbit, it's probably better suited to its intended purpose as a fire starter (to be fair, Ultimate Survival Technologies promotes the WetFire Tinder as being first and foremost a fire starter that could potentially be used to cook in emergencies and I think that's a good assessment).
One thing all of these tablets had in common was that the effective flame diminished the longer they burned. For example, while the Esbit tab burned for over 14 minutes, the strength of the flame weakened significantly about 3 or 4 minutes before it went out. So, I'd say the effective cooking time is actually more like 9-10 minutes. This was under ideal conditions so in the field, it might be less. 9 minutes is enough to boil water but I just wanted to underscore that there is a big difference between the stated total burn time on the package and the effective cooking time.
Another consideration is that the tablets are different sizes. The WetFire Tinder is significantly smaller than the Esbit tab so maybe using 1 1/2 - 2 tabs would make it more effective for cooking. That doesn't eliminate the residue on the bottom of your pot but it might help you out in a pinch.
Overall, I'm still not impressed with solid fuel tablets for cooking but definitely see a need for having a few in your emergency kit for backup or fire starting. When I need to boil a couple of cups of water for my dehydrated meals, I'm sticking with a good old alcohol stove.
What's your experience with solid fuel tablets? Love them? Hate them? Friends with benefits?