Many articles describing the creation of in vitro meat describe the growth process as “in a bath of nutrients” as if “nutrients” here means anything. So let’s break down what is actually used. Some of the most common mammalian cell culture basal medium formulations consist of what you might expect a cell needs to survive, namely amino acids, salts, vitamins, and sugar (Figure 6). The cells are grown in an incubator warmed to 37 degrees Celsius (body temperature) and typically 5% CO2, which mimics blood CO2 levels of ~40 mmHg and predominantly acts as a pH buffer in the form of bicarbonate (HCO3-). The cell culture medium is replaced every 24-72 hours, depending on the amount and metabolic rate of the cells being worked with. This removes cellular waste products, dead cells, and restores pH balance so that the cells can keep living. All told, it mimics the environment found in the body fairly well but can be improved upon by furthering our understanding of biology and having future robotic monitoring and control of cell culture conditions.