If a liquid has a vapor pressure of greater than atmospheric pressure, that liquid boils.

FORBES: Why Spring Means Higher Gasoline Prices

The gasoline must have the proper octane, and it must have the proper Reid vapor pressure (RVP).

FORBES: Why Spring Means Higher Gasoline Prices

For example, when you heat a pan of water the vapor pressure increases until it reaches atmospheric pressure.

FORBES: Why Spring Means Higher Gasoline Prices

Biobutanol has greater tolerance of moisture and lower vapor pressure, says DuPont Chief Innovation Officer Thomas Connelly .

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The RVP is based on a test that measures vapor pressure of the gasoline blend at 100 degrees F.

FORBES: Why Spring Means Higher Gasoline Prices

Butane, which has an RVP of 52 psi, can be blended into gasoline in higher proportions in the winter because the vapor pressure allowance is higher.

FORBES: Why Spring Means Higher Gasoline Prices

If, on the other hand, you were to buy summer gasoline and try to store it until winter, you might find yourself having problems getting the fuel to ignite, due to the lower vapor pressure.

FORBES: Why Spring Means Higher Gasoline Prices