Option 1: Ethanol is a breakdown product of glucose during fermentation, which occurs in the absence of oxygen. During fermentation, glucose is converted into ethanol and carbon dioxide. Therefore, option 1 is a breakdown product of glucose, so it is not the correct answer.

Option 2: Lactic acid is a breakdown product of glucose during anaerobic respiration, which occurs in the absence of oxygen. During anaerobic respiration, glucose is converted into lactic acid. Therefore, option 2 is a breakdown product of glucose, so it is not the correct answer.

Option 3: Water is not a breakdown product of glucose during respiration. During aerobic respiration, glucose is completely oxidized to produce carbon dioxide and water. This water is formed through the combination of oxygen and hydrogen molecules.

Option 4: Methanol is not a breakdown product of glucose during respiration. Methanol is derived from the oxidation of methanol, not glucose. Therefore, option 4 is the correct answer.

In conclusion, the correct answer is option 4 because methanol is not a breakdown product of glucose during respiration.