Someone sent me this email:
Quote

I don't know what you guys are paying for gasoline....Here in
California we are also paying higher, up to $3.50 per gallon. But my line of work
is in petroleum for about 31 years now, so here are some tricks to get
more of your money's worth for every gallon.


Here at the Kinder Morgan Pipeline where I work in San Jose, CA we
deliver about 4 million gallons in a 24-hour period thru the pipeline. One
day is DIESEL the next day is jet fuel, and gasoline, regular and premium grades.
We have 34-storage tanks here with a total capacity of 16,800,000 gallons.

Only buy or fill up your car or truck in the early morning when the ground
temperature is still cold. Remember that all service stations have
their storage tanks buried below ground. The colder the ground the more
dense the gasoline, when it gets warmer gasoline expands, so buying in the
afternoon or in the evening....your gallon is not exactly a gallon.

In the petroleum business, the specific gravity and the temperature of the
gasoline, diesel and jet fuel, ethanol and other petroleum products
plays an important role. A 1-degree RISE in temperature is a big deal for this
business. But the service stations do not have temperature compensation at
the pumps.

When you're filling up do not squeeze the trigger of the nozzle to a fast
mode. If you look you will see that the trigger has three (3) stages: low,
MIDDLE, and high. In slow mode you should be pumping on low speed, thereby
minimizing the vapors that are created while you are pumping.

All hoses at the pump have a vapor return. If you are pumping on the fast
rate, some of the liquid that goes to your tank becomes vapor.  Those vapors
are being sucked up and back into the underground storage tank so you're
getting less worth for your money.

One of the most important tips is to fill up when your gas tank is
HALF FULL or HALF EMPTY. The reason for this is, the more gas you have in
your tank the less air occupying its empty space. Gasoline evaporates faster
than you can imagine. Gasoline storage tanks have an internal floating roof.

This roof serves as ZERO clearance between the gas and the atmosphere,so it
minimizes the EVAPORATION. Unlike service stations, here where I work, every
truck that we load is temperature compensated so that every gallon is
actually the exact amount.

Another reminder. If there is a gasoline truck pumping into the storage
tanks when you stop to buy gas, DO NOT fill up--most likely the gasoline is
being stirred up as the gas is being delivered, and you might pick up some
of the dirt that normally settles on the bottom. Hope this will
help you get the most value for your money.

Gasoline volume changes approximately 0.125% for every 1ºC change in temperature (0.058%/ºF) .  The energy content of a gallon of gasoline purchased by a motorist in Nome, Alaska in January could, theoretically, be as much as 8-10% greater that that of a gallon of gasoline purchased by a motorist in Phoenix, Arizona in July.

Tanks are buried 2-3 meters below the ground, so it's doubtful that surface temperature has much (if any) effect on the gasoline.

Tanks are buried 2-3 meters below the ground, so it's doubtful that surface temperature has much (if any) effect on the gasoline.