Background
Carbonated beverages lose effervescence, and eventually go “flat,” after their containers have been opened. For Champagne, a noticeable decrease in quality can take place in a matter of hours.
This phenomenon strongly influences the manner in which sparkling wines are marketed, sold, and consumed. A typical consumer, for example, is unlikely to open a bottle of sparkling wine to have just one glass, knowing that the unused portion will soon go to waste. Indeed, this may be why Champagne is traditionally regarded as a beverage for special occasions, where waste is of little concern.
Waste is of great concern, however, to restaurants. It is not uncommon for restaurants that serve sparkling wines by the glass to discard several thousand dollars of product per year, and that amount grows with the number and cost of the brands kept available for by-the-glass sales. Consequently, while many restaurants serve an interesting variety of still wines by the glass, relatively few serve more than a single variety of inexpensive sparkling wine by the glass.
The ephemeral nature of Champagne partially explains why the level of connoisseurship—and the level of sales—for sparkling wines is lower than for other wines. Wine enthusiasts tend to buy the wines they understand the best, and one learns about wines by tasting critically a large variety of them, especially in a structured manner. As a practical matter, this is much more difficult and expensive to do with sparkling wines than with other wines.
There is, however, no inherent reason why this must be so. If there were a product that could safely, inexpensively, and effectively preserve sparkling wines once opened, consumers could enjoy Champagne in any amount at any time, whether at home or in a restaurant. Patterns of sparkling wine consumption and connoisseurship would change dramatically, with enormous benefits to the wine industry and consumers.
Attempted Solutions
In the several centuries since Champagne was invented, a significant body of work has accumulated on the problem of preserving opened bottles of sparkling wine—as well as some persistent myths. One of the most common myths, for example, holds that a silver spoon placed handle-first in the neck of an open bottle will maintain the carbonation of the beverage within. This method is completely without foundation.
A method with some merit is the commonly used spring-loaded pressure cap, produced by dozens of manufacturers. This passive device is designed to hold escaping carbon dioxide gas within the confines of the bottle, until the pressure in the headspace (i.e., the enclosed volume above the liquid) is sufficient to prevent further net escape of gas from the beverage. The flaw in this method is that the gas in the headspace comes at the expense of dissolved gas in the liquid; hence, each time the cap is removed, the carbon dioxide in the beverage is further depleted.
There are several cap-like devices commonly available through wine shops that purport to preserve sparkling wines, or other carbonated beverages, by repressurizing the opened container with air. By adding a pressurized gas, these devices appear at first glance to address the shortcoming of the passive cap described above.
However, these devices turn out to be even worse than the passive cap at what they claim to do. First, air contains oxygen gas, the agent of oxidation and the greatest enemy of wine. Second, pressurized air cannot, even in principle, be used to keep carbon dioxide in solution. Only pressurized carbon dioxide gas in the headspace will keep dissolved carbon dioxide gas in solution (see The Physics of Perlage page under “The Physics of Gases in Solution” for a detailed explanation of why this is so).
Last, these devices provide no protection against an inadvertent rupture of the repressurized bottle. While a bottle of unopened sparkling wine is fairly safe, a nearly empty repressurized bottle is a bigger concern, since the volume of compressed gas—and hence the stored energy—is higher.
There is one device on the market that uses pressurized carbon dioxide instead of air, but the pressure is too low to properly preserve the Champagne for extended periods, it has no safety enclosure, and it is expensive.
There are a number of satisfactory products on the market for preserving opened bottles of “still” (uncarbonated) wines. Several products use inert gases (chiefly nitrogen) at atmospheric pressure to displace oxygen in the headspace of the opened bottle, thus reducing oxidation. Another product uses a cap and pump to produce a partial vacuum in the headspace to reduce the amount of oxygen in contact with the wine. These products, however, are of no value for Champagne, since they do nothing to preserve carbonation.
The Perlage System
Now, after 300 years, the problem has been solved. The apparatus and method for safely and effectively resealing opened bottles of sparkling wine (or any carbonated beverage) and preserving them indefinitely now exists. The product is called the Perlage System (U.S. Patent number 5,635,232).
The basic process is this: an opened bottle of sparkling wine is placed in a bottle-shaped safety enclosure, the bottom of which is removable via a quick-release “twist break.” A threaded cap on the top of the enclosure is tightened to create a seal against the lip of the bottle. Pressurized carbon dioxide from a regulated, refillable gas cylinder is then injected through a one-way valve in the cap, pressurizing the headspace of the bottle back to its original condition.
The design of the regulator ensures that the pressure of the gaseous carbon dioxide in the headspace exactly matches the vapor pressure of the dissolved carbon dioxide in the liquid. Matching these two pressures prevents any net decrease in dissolved carbonation in the wine, for as long as the proper pressure is maintained. In other words, once properly repressurized, the sparkling wine is prevented from going flat—indefinitely. Also, since CO2 is a preservative, the flavor profile of the wine is also stabilized.
When the wine is next ready to be poured, the cap is simply removed. The wine can then be poured without removing the bottle from the enclosure. When the Champagne is finished, the bottom portion of the enclosure twists off for easy removal of the bottle.
Product Performance and Design Criteria
The Perlage System embodies the five characteristics deemed crucial for consumer acceptance of such a product:
1) It does not degrade the wine in any way.
The Perlage System preserves the original character of both the liquid and gas components of the wine indefinitely. Since the CO2 pressure introduced into the bottle matches the original concentration of dissolved CO2, a state of equilibrium occurs so there is no net loss of carbonation from the liquid—that is, the Champagne never goes flat. Furthermore, if all oxygen has been purged from the bottle before repressurization, no oxidation of the wine can occur, and the resealed bottle will keep indefinitely.
This point has been established in dozens of blind and double-blind taste tests with wine experts.
2) It is safe.
The method described herein involves repressurizing the original glass bottle, which, if done incorrectly, can be hazardous. There must be no possibility of the customer using the product in a dangerous manner. This is perhaps the most important design element of The Perlage System: The full-bottle enclosure serves as a non-defeatable safety feature that a) prevents the bottle from being pressurized if it is not correctly installed; b) prevents the bottle from breaking once it is properly pressurized, and c) is designed to contain the glass in the highly unlikely event of breakage. There is virtually no way to use the product in a dangerous manner.
3) It is quick and easy to use.
Restaurants can be busy places. For a device to be useful, it must first be used; for it to be used, it should take only seconds to operate, and present no special maintenance or sanitation problems. With this in mind, the Perlage System was designed to take less than five seconds to remove and replace the cap and repressurize the bottle.
4) It requires little extra space in a restaurant.
Space behind the bar is at a premium in a restaurant. The Perlage System was designed to fit easily in existing refrigerators, upright or horizontally. The bottle enclosure itself is only slightly larger than the bottle itself, and the gas cylinder is about the size of a home fire extinguisher. The whole apparatus can easily fit under the bar or in a home wine cellar.
5) It does not interfere with the established traditions of sparkling wine connoisseurship.
The Perlage System satisfies this requirement because the customer need never see the product or be aware of its use—if that is considered desirable—because of the quick-release feature of the enclosure. The bottle can be easily removed from the enclosure in seconds and delivered to the customer’s table. (Conversely, a restaurant may choose to prominently display the System as a marketing tool.)
The Perlage System has all of the attributes of a product that will be used, useful, and valued.
