The essay is too short to be considered for full scoring considerations. Providing only the minimum word count will not help increase the scoring allowance of the essay. The total essay should number between 175 - 200 words. Never instruct the reader to look at the image either. That is because this is a reporting essay that explains the procedure to the reader.
There cannot be "7 main stages". There can only be one main stage in this case, with other "manufacturing stages" involved. Such a mistake in reference presentation shows that the writer does not have a good grasp of English words, its meaning, and how these are used in sentence structuring.
boiled by heat
Another incorrect grammar reference. Boiling is, by default, done by heat and is self explanatory to the reader. I believe that the exam taker should focus on his vocabulary development and how these are used in sentences.
juice
syrups
Incorrect usage of S v. P. Once a reference is made in singular at the start, it cannot suddenly be changed into plural form towards the end.
Overall, the problems in the essay involve sentence structure and correct word usage. These should be the focus of the student's ESL classes so that he can improve his writing skills.