Sparkling wines

SPARKLING WINES
Sparkling wines are wines that contain a residual level of CO2 . The CO2 , ____________________ added or produced by an internal secondary fermentation , changes the taste perceptions of sweetness , acidity and astringency . In addition , escaping bubbles can be visualIy attractive ( sparkle ) .
There are three ____________________ methods of making sparkling wine :
1 ) Carbonation : ____________________ wine is that to which CO2 has been added from any source other than by its own fermentation , in excess of 100 kPa pressure .
2 ) bulk fermentation ( the Charmat method ) : sparkling wine must be made by a complete , or partial , fermentation of the sugar content , and be charged with CO2 . Sugar and / or wine spirit may be added ;
3 ) the classic champagne method ( méthode champénoise ) : champagne must be produced by the traditional method of fermentation in a ____________________ of less than 5 L capacity , and aged on the ____________________ for not less than 6 months ; .
However carbonation is achieved , all sparkling wines originate from a 'base wine' , which is invariably ____________________ and fermented in a conventional way .
The level of carbonation in a sparkling wine can be known measuring the amount of internal pressure in the finished bottle at a given temperature ( usually expressed in atmospheres , or bars ) . The SI unit of pressure is the Pascal . One bar pressure is equivalent to 100 kPa and 0 . 9869 atmospheres ( i . e . one atmosphere = 101 . 327 kPa ) .
The Champagne Method
The most complex and most traditional means of gaining carbonation in wine is via a ____________________ ____________________ by Saccharomyces cerevisiae , and the most notable ex ample is , of course , champagne .
The Champagne Appellation has some of the strictest , most exacting standards for growing , producing and labelling in all of the wine world .
The classic grape varieties of Champagne are Pinot Noir or Chardonnay .
Grapes are picked ____________________ in the season than those for still wines , so the high level of organic acids will have a ____________________ effect during the long processing . The accordingly lower sugar levels will mean lower levels of alcohol during primary fermentation , but this will be compensated for during secondary fermentation in bottle .
The hand - picked grapes are ____________________ pressed , ensuring minimal contact between juice and broken skins . Skin fragments and other gross impurities can be settled out of the juice ( clarification ) at normal cellar temperatures or chilling to - 5°C if necessary . Bentonite is sometimes used as an aid to sedimentation , but there is a danger of over - fìning , which can decrease the flavour complexity of the final product . The more the material that is settled out at this stage , the more stable the finished wine will be .
Clarified juice is then fermented into base wine . The most renowned houses still ferment in oak barrels , but stainless steel vats are now commonly used . Cultured yeasts are being increasingly employed , which eliminates most of the elements of unpredictability during vinification but can decrease the complexity . After primary fermentation , the wine is settled to achieve some degree of stabilisation . This is preferably carried out at reduced temperature so that further , unwanted yeast enzyme activity is discouraged .
The wine is then racked off from the sediment and further clarified before being blended ( assemblage ) . Assemblage is probably the most critical stage in the convoluted process of making champagne because the blender has to envisage how a series of often hard , acidic and thin base wines will behave after blending , and respond to a secondary fermentation before producing a memorable wine . The blenders at Moét & Chandon , for example , often have up to 300 base wines from any one vintage to deal with . The possible permutations are incalculable .
Once a suitable blend has been established , called the cuvée , the wine needs to be clarified ( collage ) once again , since the combination of so many different base wines invariably causes a deposit to be thrown ( ____________________ then again cold stabilization ) .
The primary fermentation usualIy results in a dry base wine * , so a source of fermentable sugar must first be added to each bottle to accommodate further yeast growth . This is usualIy effected adding a solution of ____________________ , or adding a small sample of reserve wine containing sucrose ( called liqueur de tirage ) , as well as adding a suitable strain of yeast ( levurage ) . The amount of sugar added depends upon the alcohol content and ____________________ required , and the amount and type of yeast added will vary according to the style of champagne . Yeast for this fermentation should be able to ferment under pressure in a reducing environment , about 10% ethanol and the presence of SO2 .
* Occasionally , the primary fermentation does not proceed to completion , and adequate sugar remains in the base wine to accommodate secondary fermentation . In such cases , the wine is transferred to another bottle and a fermentation is allowed to resume to completion . This is known as méthode rurale or méthode ancestrale .
Once alI components are in place , the bottles are ____________________ ( tirage ) with crown caps and stored . The CO2 liberated during secondary fermentation cannot escape , and the resultant pressure demands that champagne bottles be constructed of ____________________ glass . During fermentation / ageing , bottles are traditionalIy stacked and separated by wooden slats ( lattes ) in such a way that if a rogue bottle explodes , the rest will be disturbed as little as possible .
Bottles are commonly stacked in a ____________________ position ( entreillage ) at temperatures of 12 - 15°C , then ____________________ takes place . Manual riddling involves the tilting and turning of bottles in a wooden rack ( pupitre ) by a skilled rémueur ( that can turn ca . 6000 bottles an hour ) . Bottles are rotated and fractionally tilted until they assume a ____________________ - down , perpendicular position , an operation that may last several months . During rotation , the sediment and gas bubbles promote sediment deposition in the bottle neck .
These days , riddling can be done automaticalIy by the 'gyropalette' invented by the Spanish house Codorniu , which considerably shortens clarification time from the minimum 8 - week rémuage to around 10 days . The gyropalette consists of a cage containing a pallet of inverted bottles that are mechanically rotated every 8 h , causing sediment to spiraI down to the neck .
Once the sediment is in this position , the wine may theoretically be stored indefinitely , with the finer champagnes being matured for up to 5 years in upside down position ( sur pointes ) .
With the sediment now in the bottle neck , the next stage is to ____________________ it by dégorgement , a process that requires extreme dexterity and speed , in order to remove the crown cap and immediately disgorge the sediment . To facilitate this , the neck of the bottle is first frozen ( calcium ____________________ bath at ca . - 24°C ) , which causes a small ice ____________________ ( containing the sediment ) to form . The bottle is then returned to an upright position , ensuring that the ice plug is still in the neck and the crown closure is removed causing the sediment - laden plug to be forcefulIy ejected . Before freezing was introduced , the operator had to remove the cap just as the bottle was being put upright before the sediment had a chance to slide back down the bottle - a method known as 'on the fly' .
Although dégorgement is essential , it can also be disruptive because it briefly exposes the wine to ____________________ . The loss of a small volume of wine during dégorgement is compensated for by topping up ( remplissage ) with a considerable quantity ( ca . 600 - 750 g L - l ) of sugar dissolved in base wine ( liqueur d'expédition ) . For a brut style of champagne , sugar was originalIy omitted from the base wine , but nowadays a low dosage ( 10 - 20 g L - l ) is incorporated .
Riddling and disgorging yeast are tedious and time - consuming processes , even when carried out automaticalIy , and over the years experiments have been carried out with the aim of using ____________________ yeast for secondary fermentation . In this method , yeast cells are entrapped in a matrix of calcium alginate , and the resultant 'yeast balls' ( called billes ) allow yeast - Iiquid interactions across the alginate barrier , but do not permit individual cells to ____________________ into the wine . The technique , which eliminates the necessity for riddling , was developed in France by Moét & Chandon . Alginate consists of two basic building blocks , D - mannuronic acid and L - guluronic acid , which form a 'double envelope' around the yeast .
Some champagnes are naturally sweet at the end of secondary fermentation and require no sugar addition before reaching the consumer . Most , however , are dry and have low pH values , and thus benefit from sweetening . The addition of sugar at this stage is by means of a syrup , and the process is called dosage . Most syrups would consist of a mixture of 65% sucrose dissolved in base wine , usually with S02 incorporated . Sweetness level can also affect the drinkers' perception of acidity , bitterness and viscosity
After dosage , bottles are now ready for ____________________ ( bourbage ) , nowadays often with a conglomerate cork with one or more discs of high - quality cork in contact with the wine . The bottle is then ____________________ ( muselet ) to prevent the cork from being blown out , and then shaken to mix in the viscous liqueur d'expédition ,
Finally , the bottle is ____________________ with foil ( habillage ) and ____________________ .
The secondary fermentation and subsequent events , makes a series of complex changes in the chemical composition of the wine , which radicalIy affect aroma , flavour and foaming ability . These reactions , many of which are enzymatic , follow a definite sequence and involve proteins , amino acids , lipids , polysaccharides and other macromolecules .
- ethanol content ____________________ by around l . 3 - l . 4% as a result of bottle fermentation . This level will decrease fractionally after dosage as a result of dilution with liqueur d'expédition ;
- acidity ____________________ slightly due to malic acid breakdown by yeast , and by precipitation of potassium hydrogen tartrate . Again , acidity might change ( rise ) after dosage if citric acid has been incorporated into the liqueur d'expédition .
- amino acid levels decrease since they are required for yeast growth . When carbon sources become depleted and the yeast becomes stressed , nitrogen compounds are excreted into the wine ( autolysis of yeast cells ) - with amino acid levels reaching a peak after about 12 months on the lees , but low levels of proteolysis can continue for years if the wine is held on lees . Depending on ageing time yeast protein may be degraded in a wide range of reactions involving compounds such as ethanol , malic acid and tartaric acid . They act as precursors of aroma and flavour compounds such as higher alcohoIs , lactones , polyamines and amino acid esters . After a period of time , however , amino acid levels decrease , especially those of alanine and arginine . This is due to them becoming de - aminated , and also because of their participation in other chemical reactions .
These dynamic fluctuations in amino acid content contribute greatly to the final flavour and aroma of a wine .
The Tank Method ( Charmat )
The tank or bulk process represents a relatively inexpensive means of producing large quantities of sparkling wine . It is also known as the closed tank or Charmat method , in honour of Eugène Charmat , who developed the technique in France during the first decade of the 20th century ( supposedly , 1907 ) . Over the intervening years , the practicalities have been modified but the method still differs from méthode champenoise , in as much as secondary fermentation takes pIace in a ____________________ , not in a ____________________ . Modern practice now means that the wine is transferred ____________________ times each into air - free tanks , which should be capable of accommodating 6 - 8 atmospheres pressure . The preferred , rather Iaborious , way of voiding the tanks of air is to fill them with water , and then replace the water with CO2 . Base wine is pumped into the first pressure tank , where sucrose and yeast suspension are added to give final concentrations of 20 g / L and 2 x 106 viable cells / mI , respectively .
This mixture is then fermented to 'dryness' ( ca . 1 . 5 g / L sugar ) at 12 - 15°C , such that the internaI pressure reaches ca . 500 kPa . The wine is then chilled to - 2 to O°C , thus causing the pressure to fall to ca . 400 kPa . The yeast is then allowed to settle over a few days before being further clarified ( centrifugation and filtration ) and introduced into a second air - free tank ( CO2 at 200 kPa ) , which will contain any sweetening material , usually consisting of sucrose , together with ascorbic acid and SO2 . This concoction is then mixed and micro - fìltered ( 0 . 45 um ) into a third pressurised tank ( CO2 at 200 kPa ) using CO2 pressure as the driving force , and from this tank the wine is then bottled under counter - pressure . All transfers are carried out at O °C or below so as to retain the desired level of dissolved gas . The Charmat method is often referred to as cuve close , and many of the French wines traded under the name of 'mousseux' are manufactured in this way .
Carbonation
This method is used for producing ____________________ sparkling wines , of what may generally be regarded as the 'spumante' type . A stabilised base wine is prepared and filtered as if it were to be bottled . It is then chilled in a tank to O°C , under a blanket of CO2 , before being passed through a carbonator ( saturator ) under CO2 pressure .
The carbonator is usually a long vertical cylinder in which the chilled wine and CO2 are mixed counter - currently with internaI baffles to induce turbulence and promote contact between gas and wine . The desired level of 'fizziness' is achieved by a combination of flow rate through the carbonator , wine temperature and gas pressure . Wine is then either sterile - filtered and bottled via a counter - pressure filler , or passed to a pressurised tank where it is stirred for a few days and then filtered and bottled . The latter protocol aids the retention of CO2 in the wine . Carbonated wines are often regarded as the 'poor relations' of the sparkling wine family , but this is usually due to the quality of the base wine , rather than any inherent fault in the carbonation process .
Certainly , carbonation does not produce the same quality of bubble , as other methods do , for inducing a sparkle .

In France , champagnes are aged for a minimum of l year and vintage ones for 3 years . The important sensory characteristies of bottle - fermented and aged sparkling wines are attributable to the autolysate flavour only obtained by ____________________ contact time . Wines with bubbles are associated with festivities and celebrations by many people . In addition to the normal criteria of taste and aroma , sparkling wine quality is assessed on the size of the bubbles - the smaller they are , the better is the wine . Significance is also attributed to their longevity ( the more persistent , the better ) and how well they are integrated into the wine . Wines made by méthode champenoise score on all these counts , being ____________________ , longer ____________________ and better ____________________ than bubbles formed by other production methods , which tend to be less 'creamy' and complex . When decent champagne is poured into a glass , the consumer sees the foam before the liquid phase .