Sludge is another intermediary in the ethanol crystal production process. It is created by fermenting yeast and plant matter in a fermenter . Its only use is to be dried in a furnace to produce ethanol crystals , which can then be used to power certain engines.
Plant matter that can be used includes vanilla flowers, tall grass, vines, lilypads, sugarcane, leaves and saplings. Other mod leaves and saplings are also supported.