Like animal-based gelatin, the agar is dissolved in the liquid in a small saucepan over medium-high heat, brought to a boil and then simmered until slightly thickened, about 5-7 minutes. It is then chilled in the refrigerator until set and typically enjoyed cold.
You can use coffee grounds in your garden or potted plants! The three main advantages to gardening with coffee grounds is that it attracts earthworms, brings organic material to the dirt and the microorganisms in the grounds are beneficial to aid the growth of the plants. Image Credit: Getty Images.
As Stathol said, I suspect it's something to do with the fact that coffee grounds are roasted, thus turning them into a form of activated carbon, which allows them to have a huge surface area to adsorb gaseous compounds. I read the wiki too..