Pressure and Aging Wine

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities, and you.

Pressure and Aging Wine

If you think that aging wine in a wine cellar is the only or even the best way, you would be wrong. A Spanish winery in the Basque Country of northern Spain submerges wine bottles underwater in its aging process. To do this, sealed crates containing hundreds of bottles of wine are lowered into the sea from the boat using a small crane. When the process was initially dismissed as a marketing gimmick, the winemaker invited established Spanish winemakers to a blind taste test to compare underwater vs. land-based aging and the underwater units rated higher. In addition to maturing in total darkness in temperatures between 54 and 65°F with the rocking motion from the sea, underwater pressure is also attributed to the improved taste. The land-based aging process is about 14.7 psi (atmospheric pressure at sea level), but in an underwater process, the pressure increases by one atmosphere for every 33 feet below the surface.

Crusoe Treasure - Underwater Aged Wine Bottles

After aging 18 months underwater, wine bottles appear as sunken treasures when they are brought to the surface.
(Source: Crusoe Treasure.)

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Using Pressure to Salvage Underwater Treasures and History

Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities and you. In this blog we’ll be discussing the role pressure plays in salvaging underwater treasures and history.

Using Pressure to Salvage Underwater Treasures and History

Finding a long lost ship that carried gold, silver or other cargo that could survive an underwater hiding place for dozens, hundreds or even thousands of years is just the beginning of an underwater salvage operation. If a simple chain or rope cannot be used to retrieve the underwater treasure, the next step is buoyancy – using the pressure difference between a fluid (gas or liquid) to exert an upward force to overcome the weight of the submerged object.

Lift bags, parachute lifting bags and other terms are used for the lower density objects that can be either open or closed structures to create the lifting force to raise a submerged item. At certain depths, air can be used as the lifting force.

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Lifting bag courtesy of Water Weights.

For an ideal gas, Boyle’s Law states that the product of pressure and volume is a constant when the temperature is held constant.

p * V = constant

In addition, every 10 meters or 33 feet of depth, the water pressure increases by an additional bar (14.5 psi) above atmospheric pressure.

As a result, the amount of air required to lift a payload depends on the weight of the load and the depth of the bag. For example, lifting 5.6 tons with air bags at a depth of 20 meters requires 5m3 of air at 3 bar (45 psia), which is a volume of 15m3 at surface pressure (1 bar or 14.5 psia).

The compressibility of air creates problems in deeper salvage operations.  As one salvage company notes, “At depth, the air in the bags will be crushed by the water pressure until it is almost as dense as the water around it.”

When the lifting structure and submersed object rise, the pressure decreases and the air inside the bag expands. This can cause a dangerous situation by accelerating the rate of ascension. Observing how far a submerged ball can be launched into the air is a rather easy demonstration of this problem.

To counter and control this effect, the pressure relief valve in one company’s enclosed floatation and salvage pontoons releases pressure at 2.5 psi above ambient pressure.

For deeper salvage operations, fluids other than air are used. In any case, the pressure difference provides the ability to raise submerged objects and understanding the forces involved enables a successful and safer process.

What do you think/Comments?
Do you have a pressure sensing question? Let me know and I’ll address it in an upcoming blog.
-Han Mai, Senior Marketing Specialist, All Sensors Corporation (hmai@allsensors.com)