How to Check Petrol-Ethanol Mix at Home Using a Graduated Cylinder

Our government's move to E20 petrol a blend of 20% ethanol and 80% petrol— s a significant step toward reducing pollution and oil imports. However, many car owners, particularly those with vehicles not compliant with this fuel, are concerned about potential issues like reduced mileage, lower performance, and long-term engine wear. This has led to concerns about whether the ethanol content is truly as advertised or potentially higher.

Fortunately, you can perform a simple and effective test at home using just a graduated cylinder and water to check the ethanol percentage in your fuel.

The Science Behind the Test

This test works on a simple principle: ethanol mixes with water, but petrol does not. When you add a fuel sample to water, any ethanol in the mixture will separate from the petrol and combine with the water. By measuring the increase in the water's volume, you can accurately determine the amount of ethanol that was in the fuel.

Step-by-Step Guide to the DIY Ethanol Test

Follow these steps carefully to ensure a reliable result.

1. Gather Your Materials
 

• A graduated cylinder: A clear, vertical measuring tube with markings. A 100 ml size is ideal for this test. There are plenty available form Flipkart and Amazon
• Water: Distilled water is best, but clean tap water will also work.
• Fuel sample: A small sample of petrol from the fuel station you want to test. you can also siphon some off from your fuel tank using plastic ladle.
   

2. Prepare the Cylinder

Start by pouring exactly 10 ml of water into the graduated cylinder. Note this initial level. The water will form the base layer.

3. Add the Fuel

Slowly and carefully pour 90 ml of your petrol sample into the same cylinder. The total volume of liquid should now be 100 ml. You will see two distinct layers: the water at the bottom and the lighter petrol floating on top.

4. Mix the Liquids

Close the top of the cylinder with a stopper or securely cover it with your thumb. Gently shake the cylinder for a few seconds. This action helps the ethanol molecules in the petrol move into and mix with the water.

5. Let It Settle

Place the cylinder on a flat, stable surface and let it sit undisturbed for 5 to 10 minutes. This allows the liquids to fully separate into two clear layers: the water-ethanol mix at the bottom and the pure petrol on top.

6. Read the New Water Level

After the liquids have separated, observe the new water level at the bottom. For example, if the level has risen from 10 ml to 28 ml, it means that 18 ml of ethanol has mixed with the water.

7. Calculate the Ethanol Percentage

To find the percentage of ethanol in your fuel, use this simple formula:

Using our example:

This result indicates that the fuel is indeed E20 petrol.

Important Safety Precautions
 

• Work in a well-ventilated area. Always perform this test outdoors or in an open space to avoid inhaling petrol fumes.
   
• Stay away from flames or sparks. Petrol is highly flammable. Keep all sources of ignition, including cigarettes, lighters, and open flames, far away from your test area.
   
• Do not reuse the tested fuel. The petrol sample you used is now contaminated with water. Do not pour it back into your vehicle's tank. Dispose of it safely and responsibly.
   
• This is a home test, not a professional lab analysis. While this method is a reliable way to check for significant discrepancies in ethanol content, it is not a substitute for a precise, laboratory-grade measurement