The measurement of density can provide important information about E85
If one suspect that some E85 contains water may a density test be
appropriate to implement?
It has been shown that an absorption test according to the method I have
developed, not are entirely reliable. Under normal circumstances should it work,
but if the fuel contains substances that lower or increase the fuel's
water-absorption capacity, is the test not accurate.
At present it is not known what substances which affect the water-absorption
for E85, so to further may one assumes that the fuel is acceptable if its
density is close to the normalized values. If the density is found to be normal
so can the absorption capacity in fact be lower or higher than a strict mix of
ethanol and gasoline can receive. In this case, pointing it at that the fuel
contains an unknown component that only affects the absorption capacity - with a
density comparable to pure ethanol. Are the density higher without that the
absorption capacity shows an increased level of water; then would the fuel be
able to contain a salt or a substance that dissolves in gasoline or ethanol. Is
it a substance or a medium, then should its density be close to the density of
You can not get a reliable density value by measuring the density of
intact E85, because the density of the gasoline component can vary quite widely.
One must first distinguish the gasoline, so that the sample only contains water
and alcohol. By adding water in E85 stratifies the gasoline component, but the
water-soluble components can not be avoided. Such an element is ether-oxygenates
or MTBE. The content of the ether-components can vary but for normal E85 are
they quite stable in quantity.
The easiest way seems to be to use an hydrometer to measure the alcohol
content. Such an analyzer could I get at City Gross. Hydro meters are usually
graded in volume (tralles).
One can start the measurement procedure by first determining the distribution
of gasoline and ethanol. It is important to know how much gasoline it is, otherwise
one not know the proportion of ethanol, either. When the proportion of gasoline is
defined can the water concentration in the ethanol component be calculated, but
if the density for the sample is less than pure ethanol - must it contain something
that is lighter than ethanol. The most likely scenario is that it then contains an
excess of ether-oxygenates.
Start by making a quantity test:
This is the E-quality without regard to MTBE - the ether-oxygenates is
assumed mainly to be in the alcohol / water part.
- Measure 50 ml E85.
- Measure 48 ml water (preferably dosing saline in the water so the separation of water/gasoline becomes more distinct).
- Mix them, seal and shake for 15 seconds. A graduated cylinder for a hydrometer is a suitable containers.
- Release the pressure, but seal the container again and let this layer in 15 minutes.
- Read the gasoline volume in milliliters after 15 minutes.
- Insert the volume into the formula: weight per cent of ethanol = 100 - (2.1 + 1.94 x
Perform an absorption test before the density test by gradually adding water to 100 ml
E85. Once you finished, can you determine the quantity of any water with this
Excel program. Then add additional water so the total volume reaches 50 ml
Let this mix separating in peace a few hours - then, can the measurement of
density be made with an hydrometer in the alcohol part. Then use this
Excel program to determine water content.
When the measurement process is complete, there are two results that can
either work together or contradict each other. So... if both of the tests
showing that the fuel contains water is it of course more likely that it really
contain water - than if only one of the samples would show it. This, together
with a test of the electrical conductivity, will further give support to this
An illustrated version follows below
It is best to first make an absorption test:
This analysis can be downloaded here.