In looking at how to create Sparkling Wines and Champagne it’s always useful to look back at how things have been done so we can move forward in our pursuit of the “stars in the glass”.
It is very conceivable that had divine intervention not interfered that the Champagne region could still be producing still wines that rivaled those of Burgundy. Until the latter half of the 17th century the still wines of Champagne were rivaled only by those of Burgundy, and the Champenois wines had begun to encroach on the export markets of the Low Countries. Throughout the 1600’s a paper and ink war arose , in Latin prose of course, between the doctors and poets of the time extolling the respective taste and natural wholesomeness of the wines. Champagne sought to create a new style of wine and in so doing discovered how to vinify light coloured wines from the Pinot Noir Grape. The new “vin gris” was only introduced in the early 1600’s. It is during this period that the first accounts of sparkling Champagne wines are found. As luck would have it these original wines were the result of a mistake. Most “vin gris” was drunk young but when shipped abroad in cask , the warm spring weather set off a secondary fermentation, that was still underway when the wines arrived. These delicate wines were then bottled and retained a more or less haphazard sparkle, which in turn raised the curiosity of the Champenois.
The 1st successful methods of capturing the “mousse” were due to the combined efforts of the monastic orders of Pierry and Epernay. The cellar master Frere Jean Oudart (1654-1742) and Dom Piere Perignon (1639-1715) were instrumental in the locations of Saint-Pierre aux Monts de Chalons and Sain-Pierre d’Hautvillers becoming the birthplace of naturally sparkling wine. The principles established during the last quarter of the 17th century remain among the most important in the production of Champagne; the technique of blending from various vineyards to obtain a finished wine superior to it’s parts, the process of clarifying sediment in the wine, and the introduction of the cork in Champagne bottles.
There have been many improvements since that first series of accidents; things such as the advent of using chaptilization during the fermentation of northern unripe grapes and the use of sugar from grape instead of cane sugar, and the method of measuring residual sugar, etc. In spite of these enhancements we as amateurs and probably few professionals are still trying to cope with how get and keep the sparkle in the bottle.
Types of Sparkling Wines
The Technology of Winemaking refers to 4 types of sparkling beverages. Sparkling beverages are classed as sparkling once the pressure gets above about 0.5 ATM.
1) Excess carbon dioxide produced by fermentation of residual sugar from the primary fermentation. This includes Alsatian, German, Loire and Italian wines. The fermentation is stopped before all of the sugar has fermented then bottle later. It’s difficult to stop the fermentation at the desired level.
2) Excess carbon dioxide from a malo-lactic fermentation. Vinho Verde wines of Northern Portugal are the best representation of this style. To secure an adequate supply of malo-lactic activity in the wine the wine must be of low alcohol content and have a high percentage of malic acid (young grapes). The process is difficult to control as the growth of bacteria is not easy to predict or even to induce. These wines might best be described as petulant having only a slight amount of carbonation, just enough to give a light crackling character. Historically the wines were also rather cloudy and were put into ceramic bottles to hide the turpidity. Today, modern Vihno Verdes go through a malo before being bottled in clear glass, but they receive a little carbonation at the time of bottling to emulate the old familiar style. Today in Portugal you can find stainless wine vessels in all sizes at the local markets. They put the young wine in these stainless containers and dispense it as needed. Malo lactic fermentation produces a blanket of carbon dioxide that keeps the wine from oxidizing and gives the wine some petulance as well.
3) Excess carbon dioxide added. This includes the so-called carbonated wines and many crackling wines and of what we’ll talk about today. We’ll cover this in a few minutes but also includes the “Charmat” process where wine are carbonated in a bulk tank either through a 2nd fermentation or injection of CO2.
4) Excess carbon dioxide from fermentation of sugar after the process of fermentation. Most of the sparkling wines of the world are produced by this procedure. Several terms such as Methode Champenoise and Method Traditional are used to describe this type.
There are multiple steps in the process. (a) Cuvee Production, (b)Tirage Additions, (c)Bottle Fermentation and Aging, (d)Riddling, (e) Disgorgement and (f)Dosage.
(a) Cuvee Production
This process can cover the aspect of the 2nd fermentation occurring in the same bottle that you purchase or in a bottle, which is then “transferred to a tank, and filtered into another bottle while under pressure.
§ Pressing is carried out immediately after picking for the juices to be light coloured – only the free run is used for quality
§ Debourage or clearing of the juice
§ 1st fermentation in the presence of sugar or added in precise amounts. A malo-lactic may also be induced.
§ Blending – about 5 months after fermentation the wines are chosen and blended to form the assemblage or Cuvee. This is the most crucial step.
§ A further filtration may occur
Carbon dioxide is available in two forms; free gas, and CO2 electrostatically bound to constituents such as proteins, polysaccharides and lipids. Makers of sparkling wine must manage their cuvée protein levels to obtain a product with minimum protein precipitation in the bottle while not detrimentally affecting carbonation. Those using bentonite as a riddling aid may want to not fine with bentonite or purposely underfine the juice or cuvée, knowing that additional protein will be bound in tirage. Little has been published about the influence of tirage fining agents on bubble and mousse. Munkegard (1998) noted the increase in mousse quality with the addition of tirage tannin.
(b) Tirage Additions
The wine is drawn and put into it’s permanent bottle, the winemaker adds the Liquer de Triage, a blend of sugar, wine and yeast that will begin the 2nd fermentation.
How is CO2 measured??
CO2 is measured in “Volumes”, where one volume is equal to one litre of CO2 dissolved into one litre of liquid. For instance at 0C with a pressure setting of 12 on your CO2 regulator you should be able to achieve a maximum CO2 content of 2.9 Volumes or 2.9 Atm’s. So how do we know what level or how many Volumes of CO2 we should be carbonating to. By comparison beers run at about 2-3 volumes of CO2, while Ciders run a little higher at about 2.5-4 Volumes of CO2 and Sparkling wines at anywhere from 2-8+ Volumes of CO2.
Theoretically, 4.04 grams of glucose or 3.84 grams of sucrose upon fermentation will yield 1.00 liter CO2. In actual practice, sparkling wine producers estimate that 4.0 to 4.3 grams of sugar per liter is needed to produce one gas volume (ATM) of carbon dioxide (4.3 grams of sugar per liter is equal to 1 pound of sugar in 27.3 gallons). If, for example, 6 gas volumes of CO2 are required, then approximately 4.2 grams times 6 atmospheres or 25.2 grams of sugar per liter are added. This will produce between 1.1-1.5% additional alcohol (v/v). If the cuvée already contains fermentable sugar, this must be taken into account.
We could add the use of dialysis tubing here. I can photo copy the article and we can briefly discuss it. I would be inclined to put the reference to dialysis closer to where it would be used in the process.
(c) Bottle Fermentation and Aging
A closure is now placed on the bottle. This usually consists of a crown cap. Following sealing, sparkling wines are stored relatively warm and then moved to a cooler place. Vintage wines are left for at least 3 years and non-vintage about 1 year. Many high value Champagnes will be on the lees for up to 7-8 years before riddling.
Show the overhead of below.
Autolysis is dependent upon such parameters as pH, ethanol concentration, and temperature.
So how does temperature affect the pressure?? Show graph of the single point graph of Pressure and temperature then the Effect of Pressure and Temperature on Carbon Dioxide Content from Vogt.
(d) Riddling
To enhance riddling ability, disgorgement, and possibly wine palatability, some vintners add riddling aids at the time of cuvée bottling. Such aids (fining agents) may enhance the riddler's ability to convey the yeast to the neck of the bottle. When there is sedimentation of the yeast with the proper fining agent, riddling can be much easier. Some common riddling aids are:
· Sodium and calcium bentonite
· Clarifying Agent C
· Adjuvant H
· Isinglass
· Tannin
· Gelatin
· Diatomaceous earth
(e) Disgorgement
The last step is the disgorgement; the bottle tops are placed into a brine (calcium chloride) salt solution to freeze the neck and sediment in the neck. The temporary bottle cap is removed and the CO2 in the bottle blasts out the frozen sediment, at which point you move your thumb very rapidly over the neck of the bottle wait for the foaming to subside then add in your dosage.
What happens during disgorgement?? Show Thermodynamics and Kinetics from Acree.
How can you measure the CO2 volume in a beverage. It’s not easy and you need something like a Zahm Hartung CO2 Volume Meter. Using this piece of equipment which measures the volume of CO2 you can use the equation
Volume of CO2 times 0.197 / specific gravity of the beverage = % CO2 weight.
(f) Dosage
Sugar in the dosage is added for the purposes of sweetening, balancing the acidity, masking astringency-bitterness and slightly modifying flavor. Extra Brut 0-6 gm/sugar / liter, brut 0-15 gm sugar, extra-sec 12-20 gm sugar, sec 17-35 gm sugar/L, demi-sec 35-50gm sugar/L and doux >50gm sugar/L. Many of the base wines of the premium Champagnes are the same just different levels of dosage are added for the market appeal.
(g) Alternatives
If you’re going to try the latter step there is a simpler way that retains much of the CO2. Leave the bottles standing upright. When you’re satisfied with the duration on which the yeast has been in the bottle, chill it to just above freezing. Don’t freeze the wine, as the crystals will play havoc with the next step. Chill another empty bottle in which you have placed the desired level of dosage, then gently release the temporary cap then very slowly pour over the very cold wine into the chilled 2nd bottle.
GUSHING
The appearance of sparkling wines is a very important quality feature affected by foaming and effervescence (amount, size and duration of bubble formation). In sparkling wines, some of the gas is free and some fixed with an equilibrium between free dissolved gas and combined gas. Particulate matter in the form of case dust, cork dust, fibers or particles from packaging materials, and possibly particles from the wine or dosage itself, can cause gushing.
If sparkling wine contains a lot of dissolved air or nitrogen under pressure, as well as carbon dioxide, gushing can occur. When bottles that contain air or nitrogen are opened, these gases immediately come out of solution as fine bubbles that then gather carbon dioxide and gush. These gases make the system unstable because their escape rates may be higher than that of the carbon dioxide.
Show the overhead of Thermodynamics & Kinetics
PRESSURE AND BOTTLE SAFETY
Champagne bottles are manufactured to withstand significant pressures that can easily exceed 100 psi. The bottle is manufactured from very thick glass. Gentle sloping shoulders and a long neck combined with the punt or indentation in the bottom of the bottle help reduce the pressure by distributing it more evenly. Do not use any other kind of bottle for sparkling wines. Clean the bottles and hold them up to a light source to inspect for cracks, scratches or imperfections.
Bottle at very low temperatures to minimize the pressure used. The warmer the wine, the higher the pressures necessary to carbonate. Store your sparkling wines at cool temperatures and never allow them to get too warm such as in a car or out in the sun. A chilled bottle of sparkling wine will have a pressure of 40 or 50 psi. If the same bottle were to reach 30 C the pressures could more than double.
CARBON DIOXIDE AND PRESSURE
Carbonating Wine
What is carbonation: It’s the process of injecting CO2 gas into a liquid to create an effervescence . In order to force carbonate a liquid two conditions have to be met; 1) the liquid must be cold enough to accept the gas (solubility), 2) the liquid must be in a sealed pressure vessel to allow the gas to be forced in under pressure.
Some sparkling wines are simply carbonated like soda pop. It is a relatively simple process, but requires some specialized equipment. Sparkling ciders can also be made with this equipment and are a little easier to deal with due to the lower pressure requirements of cider.
- CO2 tank
- Gas pressure regulator 60-100 psi
- Cornelius Kegs which are those stainless kegs that soda pop comes in
- Carbonating stone
o These are made of ceramic or sintered stainless with very small openings which produce very small bubbles when CO2 is forced through them. Very small bubbles have a large surface area of exposure and are easily dissolved in the wine.
- Various hoses and connectors
- Counter pressure bottler such as Melvico
It is important to start with a balanced finished wine that has been fined and filtered and is ready to bottle. Carbonation lends itself best to light, aromatic wines with balanced acidity and a small amount of residual sugar.
1) Sanitize all your equipment. It’s a good idea to pump sanitizer through the lines with CO2 and then rinse well before proceeding.
2) Transfer the wine to the keg by siphoning without aerating. Fill the keg about ¾ full.
3) Replace the lid and lock down. Pressurize the keg to seat the lid with 10 –15 psi.
4) The keg of wine is now ready to be chilled. The colder the wine, the better the CO2 will dissolve. Why cold: carbon dioxide is soluble in a solution in an inverse relationship to the temperature of the solution, think about opening a pop can on a warm summers day.
5) It is now time to carbonate the wine. Attach the CO2 line to the IN keg connector.
6) The carbonating pressures are related to the type of beverage and temperature. If the keg has been chilled to approximately 0C, adjust the regulator to 25 psi for cider and 35 psi for sparkling wine. You will now hear the gas entering the keg.
7) Hold the keg on its side and roll it back and forth. You will hear the gas bubbling in the keg and the gas traveling though the regulator. Continue for about 10 minutes or until you no longer hear anything.
8) The cider or wine is now carbonated and can be stored indefinitely. It does need to rest for a while before dispensing or bottling.
Dispensing
Cider can be dispensed right from the keg if you have a way to keep it chilled. Release the pressure using the pressure release valve on the lid of the keg. Adjust the regulator pressure to 5 to 8 psi. Attach the dispensing hose and tap to the OUT keg connector and dispense at these low pressures. If you attempt to use a higher pressure the dispensing hose and tap will fail and there will be too much foam. Because of the larger amounts of dissolved CO2 and the higher pressures it is difficult to dispense sparkling wine.
Bottling
1) Sparkling cider can be bottled directly from the tank with some CO2 loss. Follow the instructions above for dispensing. Chill both the cider and your bottles to around 0C or lower. Slowly dispense directly into the bottle and immediately seal.
2) Sparkling cider and wine can also be bottled, using counter-pressure bottling equipment. A local brew on premise will most likely have the equipment or it can be purchased.
3) Follow the specific manufacturer’s instructions
4) The counter-pressure bottler, pressurizes the bottle to the same pressure as the sparkling wine or cider. The liquid slowly enters the bottle and, when full, the pressure is gradually released. A closure is then promptly applied.
Carbonators
1) Carbonators are simply a bottle cap with an air valve attached.
2) Fill a 2 L plastic soda pop bottle with wine or cider.
3) Screw on the carbonator cap and pressurize the bottle with CO2.
4) Proceed as above to dissolve the CO2.
5) Remove the Carbonator and apply a normal cap.
