Does warmer storage make cow manure produce more methane gas? You fill three sealed flasks with equal amounts of manure and water. One flask goes in a refrigerator at 14 degrees Celsius. One stays at room temperature (24 degrees Celsius). The third sits on a hot plate at 34 degrees Celsius. A tube from each flask leads to an inverted water-filled measuring cylinder. As bacteria break down the manure without oxygen, methane gas collects in the cylinder. You record gas levels daily for five days. The flask kept at 34 degrees Celsius produced the most methane by a wide margin.