Water Test for WVO

Search this site!

If there is water present in your WVO, it can cause problems. It can lower the yield, cause washing and emulsion problems, slow down the reaction, and cause soap formation. Below are several methods you can use to tell if there is water present.

...if there IS water in your WVO, you will want to determine if it is an acceptable amount to deal with (here's how to remove water ), or if you should look for another oil source.

Pan Method:

The basic idea behind this test is that you will place the oil sample on a pan hot enough to make water boil, you will see the presence of water through tiny bubbles coming through the oil.

• Smear a bit of oil on the bottom of a heavy cast iron pan, turn the heat on high and wait for it to smoke.

• Now, pour a small quantity of the oil onto the very hot pan and watch for bubbles. If there are any bubbles it means water is present. Pure oil will not bubble at all.

• Here's how to tell how much water you have:

- Spattering oil means it has a LOT of water in it.

- If it sizzles, it’s pretty wet.

- If it just shows a few small bubbles, it is nearly dry.

- If there are no bubbles at all, it’s all the way dry.

Quantitative Water Test:

The basic idea of this test is that you will weigh the oil sample, boil the water off, weigh the oil again, and calculate the percentage of water that was present.

• To begin, thoroughly mix your batch of oil so the water is evenly dispersed.

• Weigh out 300-400 ml of oil.

• Bring the oil sample to above water’s boiling point at 212°F or 100°C. Boil, while mixing until all there are no more bubbles, then let cool.

• Weigh the now dry oil.

• Here's how to calculate how much water was present:

- Use a scale accurate to 0.1 gram or better.

- Take the weight of the dried oil and subtract it from the wet oil weight. (This gives you the weight of the water that was removed.)

- Divide the weight of the water by the wet oil weight.

- Multiply the resulting number by 100 to for the percent water content of your WVO.

Water Test Kit:

You will add a sample of the WVO and calcium hydride into the testing unit. The calcium hydride reacts with water in the oil to form hydrogen gas. The testing unit gives a reading of water content based on how much pressure there is. ...it only takes five minutes for the results!


Dry to almost dry oil can be used to produce biodiesel, but highly wet oil will cause too many problems and too much energy to remove. Find another oil source. Oil that is changed every week is a good bet.

Return from 'WVO' to 'Oil Collection'

Biodiesel Homepage