Well, I tried very hard to find some science to prove "my theory" but I simply can't.
That said, I also have zero experience at degassing at sea level, only at high altitude which I can guarantee is hard but in reality it is quite probably harder to degas at sea level than at altitude.......
So lets look at some of the science behind the things we are interested in!
Solubility of Gases vs. Temperature:
The variation of solubility for a gas with temperature can be determined by examining the 1st graphic below.
As the temperature increases, the solubility of a gas decreases as shown by the downward trend in the graph .
More gas is present in a solution with a lower (colder) temperature compared to a solution with a higher (warmer) temperature.
The reason for this gas solubility relationship with temperature is very similar to the reason that vapor pressure increases with temperature. Increased temperature causes an increase in kinetic energy. The higher kinetic energy causes more motion in molecules which break intermolecular bonds and escape from solution.
This gas solubility relationship can be remembered if you think about what happens to a "soda pop" as it stands around for awhile at room temperature. The taste is very "flat" since more of the "tangy" carbon dioxide bubbles have escaped. Boiled water also tastes "flat" because all of the oxygen gas has been removed by heating.
So this is why we always tell people to warm that carboy up to 75 degrees 1st before attempting to degas!
Moving on to what we really want to look at in this thread!
Gas Pressure and Solubility:
Liquids and solids exhibit practically no change of solubility with changes in pressure.
Gases however, increase in solubility with an increase in pressure.
Henry's Law states that: The solubility of a gas in a liquid is directly proportional to the pressure of that gas above the surface of the solution.
Remember atmospheric pressure is
Higher at sea level than at high altitude. You have less pressure at high altitude because there is less atmosphere weighing down on you in other words.
Now we are getting to the nitty gritty!
If the pressure is increased (think sea level), the gas molecules are "forced" more into the solution since this will best relieve the pressure that has been applied. The number of gas molecules is decreased. The number of gas molecules dissolved in solution has increased as shown in the 2nd graphic below.
Carbonated beverages provide the best example of this phenomena. All carbonated beverages are bottled under pressure to increase the carbon dioxide dissolved in solution. When the bottle is opened, the pressure above the solution decreases. As a result, the solution effervesces and some of the carbon dioxide bubbles off.
Deep sea divers may experience a condition called the "bends" if they do not readjust slowly to the lower pressure at the surface. As a result of breathing compressed air and being subjected to high pressures caused by water depth, the amount of nitrogen dissolved in blood and other tissues increases. If the diver returns to the surface too rapidly, the nitrogen forms bubbles in the blood as it becomes less soluble due to a decrease in pressure. The nitrogen bubbles can cause great pain and possibly death.
To alleviate this problem somewhat, artificial breathing mixtures of oxygen and helium are used. Helium is only one-fifth as soluble in blood as nitrogen. As a result, there is less dissolved gas to form bubbles.
Another application of Henry's Law is in the administration of anesthetic gases. If the partial pressure of the anesthetic gas is increased, the anesthetic solubility increases in the blood.
The amount of dissolved oxygen in a mountain lake at 10,000 ft and 50 degrees F is less than the amount of dissolved oxygen in a lake near sea level at 50 degrees F because of less atmospheric pressure at high altitude.
A Coke at room temperature will have more carbon dioxide in the head space above the liquid than an ice cold bottle because a warm coke can hold less of the gas in solution.
So if your still reading this you must be really bored or very interested in the science behind degassing of wine at different temperatures and pressures!
Anyone's head hurt yet?
).
. When in doubt, ask the internet!
