Edit: They are jars of liquid culture mix with no agar. For liquid culture, it’s a similar nutrition base but does not solidify: corn sugar, malt extract and some peptone mixed with water.
I’ll start making agar plates and slants for cloning or starting from spores. (Germination of spores in agar is ideal as I can spot and separate contamination much easier. Spore collection and use, by nature, is not sterile. Since I am growing in a controlled environment where pasteurization or sterilization is used, rando spores that are floating around in the air could easily destroy my cultures.)