No, you most certainly haven't.
First off - boiling water is not sufficient to sterilize it. Even if you could raise the water to your 215 F (101 C) point (unless you live beside the Dead Sea you won't be able to) For sterilization of solid and liquid substances usually this is done with temperatures between 121 C (250 F) and 132 C (270 F) for times between 30 and 60 minutes. The only way you can achieve this with substances that contain water (e.g. your sweet potato) is to raise the pressure in the surrounding container so that the boiling point of water is raised to the temperatures above.
The risk you run with your idea is that (as noted in comment by @RonBeyer)) is that endospore-forming bacteria and fungal species are generally not killed by heating water to it's boiling point. You may reduce the numbers of bacteria present, but you can't generally eliminate them. These bacteria can then exit their endospore phase and start growing. Once they grow, they will spoil your food and potentially make you very sick if you were to eat it. Endospore forming bacteria include some of the more significant human pathogens such as Bacillus anthracis (anthrax) and Clostridium species (colitis (C. difficile), relevant to food poisoning: (C. perfringens), and tetanus (C. tetani)). None of which you want to get!
However, even autoclaving isn't sufficient to kill all bacterial species (see my answer on the Biology SE), but most of these highly resistant species are not pathogens that we know of. However, one of the more resistant genera Desulfotomaculum is a soil bacterium (where sweet potato grow...) and a significant spoiler of canned foods.
Long story short: DON'T DO IT!