Click on a question below.
Frequently Asked Questions
Where does the name of the product come from?
Briefly, how does the Perlage System work?
What is the purpose of the shell? Why not just have a cap?
Will the size and quality of the bubbles in the Champagne be the same after it is repressurized using the Perlage System?
Do high-quality Champagnes have smaller bubbles than lesser Champagnes?
What if the carbon dioxide in the cylinder is impure? Could it affect the flavor?
How long will an opened bottle of Champagne keep in the Perlage System?
How does the Perlage System “know” how much carbon dioxide to put in the bottle as the volume of the headspace changes?
Most Champagnes are bottled around 90 psi, or about six atmospheres. The Perlage System uses 65 psi. Why is this?
Can the Perlage System be used for still wines?
With the hand-held filler, how many uses per cartridge do you get?
Advanced FAQ
The gases that escape from Champagne as it is opened are a complex mixture of many compounds, but the headspace is repressurized with pure CO2. Doesn’t this affect the composition of the wine?
How is it possible that the Champagne will have the same bouquet after being repressurized with pure carbon dioxide?
How can it be that there simply is no difference between CO2 that has been in the bottle for years and CO2 that is freshly added?
Some wine makers say that there are certain processes that bind CO2 molecules to various compounds in the Champagne, and that these reactions require lengthy secondary fermentations. Is this true?
Doesn’t the Perlage System run afoul of EU/French appellation laws on the basis that the carbon dioxide in the headspace of a bottle in Perlage didn’t come from yeast cells during secondary fermentation?
Q: Where does the name of the product come from?
A: From the French Perlage (pear lahjz), meaning “of or relating to the quality of the bubbles in Champagne.”
Q: Briefly, how does the Perlage System work?
A: After a bottle of Champagne has been opened and partially consumed, it is placed inside of the Perlage enclosure. Air in the headspace of the bottle is then purged with pure CO2 (air unavoidably flows into the bottle as the wine is poured out, and it should be removed to prevent oxidation). A cap with a seal and a one-way valve is then affixed to the shell, creating a seal with the lip of the bottle. The bottle is then repressurized with pure CO2 to exactly the same pressure that existed in the headspace just before the bottle was opened.
This keeps the level of carbonation in the Champagne constant until the next serving, and preserves the flavor profile of the wine. In short, if the headspace of the bottle is returned to its original condition, there is no physical or chemical mechanism that could cause the Champagne to change—to put it colloquially, the Champagne doesn’t “know” that it has been opened.
Q: What is the purpose of the shell? Why not just have a cap?
A: The shell is there for safety. It is designed to prevent the bottle from breaking as the result of an impact or from being dropped, and in the extremely unlikely event that the bottle were to break, the shell would safely contain the glass fragments. This is not much of a concern when the bottle is nearly full, as the volume of compressed gas in the headspace is relatively small. In a nearly empty bottle, however, the volume of compressed gas is much greater, making the shell more important. This safety feature is non-defeatable: the bottle simply cannot be pressurized unless it is correctly placed in the shell. (The shell itself is not pressurized—only the bottle is pressurized.)
Q: Will the size and quality of the bubbles in the Champagne be the same after it is repressurized using the Perlage System?
A: Yes. The size and quality of the bubbles in Champagne—or any carbonated beverage, for that matter—is determined primarily by the chemical and physical characteristics of the liquid, such as surface tension, viscosity, concentration of proteins and other surfactants, and the like. These characteristics are a unique signature of the long and complex process of producing a quality Champagne, and it is these characteristics that determine the nature of the bubbles, not the carbon dioxide itself. In other words, if one were to completely flatten a bottle of Champagne by agitating it, thus removing all of the CO2 produced during secondary fermentation, and then recarbonate it using the Perlage System, the quality of the bubbles would be exactly the same as the original Champagne, because the chemical and physical properties of the liquid would be unchanged. The quality of the bubbles does not depend on whether the carbon dioxide molecules came from yeast cells or the Perlage System.
Q: Do high-quality Champagnes have smaller bubbles than lesser Champagnes?
A: Maybe, but not necessarily. The long secondary fermentation that a high-quality Champagne undergoes gives rise to a vast array of complex compounds from yeast autolysis and other chemical and biological processes that may not be present in cheaper, bulk carbonated sparkling wines. Some of these compounds may contribute to conditions that lead to smaller bubble size, all other things being equal. However, bubble size is much more strongly influenced simply by the concentration of carbon dioxide in the wine—the less CO2 in the liquid, the smaller the bubbles (note how the bubbles in a glass of Champagne get smaller and less frequent the longer it sits). Since the best Champagnes tend to be aged in the bottle for years, and cork is very slightly porous, the older, better Champagnes may tend to have lower carbon dioxide levels, and hence smaller bubbles, simply because some of the CO2 has escaped.
Q: What if the carbon dioxide in the cylinder is impure? Could it be dangerous, or at least affect the flavor?
A: Impurities in the CO2 could indeed affect the flavor. However, this is extremely rare. The bottled CO2 available to restaurants is food grade and FDA approved. Any time you order a beer on tap or a soft drink from a soda dispenser at a restaurant, every bit of CO2 that pushes the beverage out of the tap comes from an industrial gas cylinder. If it is safe enough for soft drinks, which have much higher consumption rates than wines, then it is safe enough for the Perlage System.
Q: How long will an opened bottle of Champagne keep in the Perlage System?
A: If the Perlage System is used properly, a resealed bottle will keep indefinitely. However, usage patterns are important: The more times a bottle opened and resealed, the more times the wine is exposed to oxygen and possibly bacteria, which will inevitably decrease the shelf life. In a typical restaurant setting, in which a given bottle is repressurized two or three times before it is finished, perceptible changes are rare over a period of two to three weeks.
Q: How does the Perlage System “know” how much carbon dioxide to put in the bottle as the volume of the headspace changes?
A: Gas is delivered to the bottle until a preset pressure is reached, regardless of how much Champagne is left in the bottle. The pressure is set to equal the headspace pressure of an unopened bottle at a typical refrigerator temperature of around 4 degrees Celsius (40 degrees F).
Q: Most Champagnes are bottled around 90 psi, or about six atmospheres. The Perlage System uses 65 psi. Why is this?
A: The 90 psi figure usually quoted is measured at 20 degrees C (68 F). Champagne is typically served around 4 C. Since gases are more soluble in liquids at lower temperatures, when a bottle is chilled, some of the CO2 in the headspace dissolves into the liquid until a new equilibrium is reached. We have found this equilibrium pressure to be around 65 psi at typical serving temperatures.
Q: Can the Perlage System be used for still wines?
A: No. A still wine placed in the Perlage System would become carbonated. It is in fact easy to produce a drinkable sparkling wine in this manner.
Q: With the hand-held filler, how many uses per cartridge do you get?
A: It depends on the exact usage pattern; specifically, how many times you repressurize the bottle. If you pour half a glass, then repressurize, pour another half glass, then repressurize, and so on, you will go through the cartridge quite quickly.
However, a more typical usage pattern is something like this: You pour two glasses for your you and your companion. Repressurize. The next day, you pour another two glasses at dinner, and repressurize. Now, since there is only one glass left (there are about five glasses of Champgane in a bottle), the next time you pour a glass, the bottle will be empty, and there is no need to repressurize it. So that was two repressurizations for the bottle. At this rate, with an average of about two repressurizations per bottle, we have found that a single cartridge will last for several bottles.
Advanced FAQ
Q: The gases that escape from Champagne as it is opened are a complex mixture of many compounds, but the headspace is repressurized with pure CO2. Doesn’t this affect the composition of the wine?
A: For all practical purposes, no. CO2 and water vapor comprise well over 99.99% of the gases in the headspace—the other compounds in the headspace exist in very small amounts. When a bottle of Champagne is opened, tiny amounts of these compounds do escape in the gaseous form. However, there is a vast reservoir of these compounds in the liquid wine that remains in the bottle, so the small amounts that are lost are relatively insignificant.
It would be possible to contrive a usage pattern where this might not be true. Imagine a case in which there is very little wine remaining in the bottle, and it is reopened and repressurized repeatedly. To the extent that components in the wine have different volatilities, they will be depleted at different rates. So it may be possible to noticeably change the relative proportion of compounds in the remaining wine, especially if the reservoir of remaining wine is small. This, however, is obviously not the typical usage pattern for the Perlage System. In typical restaurant scenarios, a given bottle is rarely repressurized more than a few times.
Q: But those other compounds in the headspace, regardless of how minuscule the concentration, are vital, and give the Champagne its characteristic aroma. So how can the Champagne have the same bouquet after being repressurized with pure carbon dioxide?
A: Champagne is composed of hundreds of chemical compounds, all volatile to some small degree, and when a bottle of Champagne is opened, tiny amounts of these compounds do escape in the gaseous form. However, as mentioned above, there is a vast reservoir of these compounds in the wine that remain in the bottle. If the bottle is resealed and repressurized, each volatile component in the wine diffuses back into the headspace until equilibrium is reached, which occurs when the partial pressure of that compound in the headspace equals its vapor pressure at that temperature. After a short time, the relative proportions of compounds in the headspace will be essentially identical to the bottle before it was opened; i.e., it will have the aroma of Champagne, not of pure carbon dioxide, the next time the bottle is opened.
Q: How can it be that there simply is no difference between CO2 that has been in the bottle for years and CO2 that is freshly added?
A: Let’s look at this on a molecular scale. Dissolved CO2 exists in several forms in solution: as free molecules, as carbonic acid, as carbonates, bound to proteins, etc. All of these reactions are dependent on pressure; in fact, the concentration of CO2 in solution depends linearly on the pressure in the headspace (this is a consequence of Henry’s Law in physics). That is, double the pressure of CO2 in the headspace at equilibrium, and the concentration of dissolved CO2 will double.
Now, at equilibrium, the situation is not static—there is a lot going on. Equilibrium just means that the rate at which molecules are going from the gaseous state to the liquid state is equal to the rate at which molecules are going from liquid to gas. Said another way, equilibrium occurs when the partial pressure of CO2 in the headspace equals the vapor pressure of CO2 at that temperature and concentration. So, if the Perlage System returns the headspace of the Champagne to the pressure that existed just prior to opening the bottle, the number of “old” CO2 molecules leaving solution is just balanced by the number of “new” CO2 molecules entering solution.
Since physics tells us there can be no difference between these molecules—a molecule that came from a yeast cell in secondary fermentation and has been in the bottle for five years is no different from one that comes from an artificial source—there simply can be no significant change in the Champagne if it is properly repressurized.
Q: Some wine makers say that there are certain processes that bind CO2 molecules to various compounds in the Champagne, and that these reactions require lengthy secondary fermentations, and cannot be recreated by rapid bulk carbonation. So surely this could contribute to some differences between an original bottle of fine Champagne and one that has been flattened and recarbonated with Perlage.
A: Let’s look at this carefully. First, if there were such processes that bound CO2 molecules more tightly than would be dictated solely by the equilibrium partial pressure of the CO2, then these molecules would be unaffected by using the Perlage System, as they would continue to stay bound when the bottle was opened and repressurized.
Second, our research has shown no difference in the rate of CO2 loss between a bottle of Champagne that has been freshly opened, and one that has been decarbonated by agitation, recarbonated with the Perlage System, and then reopened. This seems to indicate that there is no difference in the behavior of “old” carbon dioxide and “new” carbon dioxide; that is, there are no tightly bound CO2 molecules that take longer to come out of solution.
Last, the intended use of the Perlage System is not to recarbonate flat Champagnes (which it will do easily), but rather to reseal and repressurize the bottles so they don’t go flat in the first place—so the question of whether there are CO2 molecules that are more tightly chemically bound than others is essentially moot.
Q: Doesn’t the Perlage System run afoul of EU/French appellation laws on the basis that the carbon dioxide in the headspace of a bottle in Perlage didn’t come from yeast cells during secondary fermentation?
A: There are several points to make here. Appellation and purity laws relate to the product as it is manufactured and sold, not as it is served to the customer. A Champagne Cocktail, for example, has other ingredients in it besides Champagne, but is not illegal to serve, because the bitters and lemon twist were added after manufacturing.
Champagne has a legal minimum for the amount of carbon dioxide that must be in solution when the product is manufactured. (In Europe, the minimum pressure for sparkling wines recommended by l'Office International de la Vigne et du Vin is 51 psi at 20°C.) If these appellation and purity regulations applied to the product as served, then a slightly flat bottle of Champagne served at a restaurant would also be in violation.
When a glass of Champagne is poured, an amount of air flows into the headspace equal to the volume of Champagne poured out. This air obviously did not come from secondary fermentation during the Methode Champenoise process either. If you put a stopper on the bottle, then you are essentially doing what the Perlage System does: trapping gas molecules that did not come from secondary fermentation in the headspace of the bottle. If the Perlage System violates appellation laws, then so does a stopper. At least the Perlage System is putting the same gas in the headspace as existed prior to opening. And remember: All molecules of a given substance are identical. It is thus impossible to distinguish molecules of CO2 that came from the yeast from those that came from the Perlage System.
