Band 9: You should spend about 20 minutes on this task. The diagram below shows how ethanol fuel is produced from corn. Summarise the information by selecting and reporting the main features and make comparisons where relevant. You should write at least 150 words.

The diagram illustrates the process of producing ethanol fuel from corn.

Overall, it is a linear process consisting of several stages, beginning with storing and milling corn and ending with the transportation of the final product. Notably, water is added during the cooking stage, and the mixture undergoes fermentation before being separated and purified.

Initially, harvested corn is stored and then milled into smaller particles. The ground corn is subsequently cooked for four hours, during which water is added to facilitate the process. After cooking, the mixture is transferred to a fermentation stage that lasts for 48 hours. This is the longest stage in the entire process and is crucial for converting the material into ethanol.

Following fermentation, the mixture is separated into two components: a solid by-product and a liquid. The liquid component then undergoes purification for five hours to produce ethanol of suitable quality. Finally, the purified ethanol is stored once more before being transported to its destination.

In summary, ethanol production from corn involves a series of mechanical and chemical steps, with fermentation and purification being the most time-consuming stages.