: In these media, the agar which is an unbranched long chain of polysaccharides is added in the concentration of 1.5-2.0%. Most commonly, 1.3% agar is used to prepare solid media in labs. The agar-containing media solidifies at 37 ºC. [1] Sometimes, in the place of agar, some other inert solidifying agents are used, such as gellan gum.