Autolysis (alcohol fermentation): Difference between revisions
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{{For|the self-destruction of cells|Autolysis (biology)}} |
{{For|the self-destruction of cells|Autolysis (biology)}} |
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[[File:Cocktail by candle light 1.jpg|right|thumb|200px|Many of the flavors associated with premium Champagne are influenced by the autolysis of the lees during winemaking.]] |
[[File:Cocktail by candle light 1.jpg|right|thumb|200px|Many of the flavors associated with premium Champagne are influenced by the autolysis of the lees during winemaking.]] |
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'''Autolysis in [[winemaking]]''' relates to the complex chemical reactions that take place when a wine spends time in contact with the [[lees (wine)|lees]], or dead [[yeast (wine)|yeast]] cells, after [[fermentation (wine)|fermentation]]. While for some [[wine]]s autolysis is undesirable, it is a vital component in shaping the flavors and mouth feel associated with premium [[Champagne (wine)|Champagne]] production.<ref name="Oxford pg 54">J. Robinson (ed) ''"The Oxford Companion to Wine"'' Third Edition pg 54 Oxford University Press 2006 ISBN 0-19-860990-6</ref><ref>Champagne Science ''"[https://www.champagnegallery.com.au/champagne-science/vinification/autolysis/ Autolysis - and its effects on Champagne]"'' Accessed: December 30th, 2008</ref> The practice of leaving a wine to age on its lees (or ''[[sur lie]]'' aging) has a long history in winemaking dating back to [[Roman winemaking]]. The chemical process and details of autolysis were not originally understood but the positive effects of a creamy mouthfeel, breadlike and floral aroma, as well as reduced astringency were noticed early on.<ref name="Oxford pg 399">J. Robinson (ed) ''"The Oxford Companion to Wine"'' Third Edition pg 399 Oxford University Press 2006 ISBN 0-19-860990-6</ref> |
'''Autolysis in [[winemaking]]''' relates to the complex chemical reactions that take place when a wine spends time in contact with the [[lees (wine)|lees]], or dead [[yeast (wine)|yeast]] cells, after [[fermentation (wine)|fermentation]]. While for some [[wine]]s autolysis is undesirable, it is a vital component in shaping the flavors and mouth feel associated with premium [[Champagne (wine)|Champagne]] production.<ref name="Oxford pg 54">J. Robinson (ed) ''"The Oxford Companion to Wine"'' Third Edition pg 54 Oxford University Press 2006 ISBN 0-19-860990-6</ref><ref>Champagne Science ''"[https://www.champagnegallery.com.au/champagne-science/vinification/autolysis/ Autolysis - and its effects on Champagne] {{wayback|url=https://www.champagnegallery.com.au/champagne-science/vinification/autolysis/ |date=20110216173031 }}"'' Accessed: December 30th, 2008</ref> The practice of leaving a wine to age on its lees (or ''[[sur lie]]'' aging) has a long history in winemaking dating back to [[Roman winemaking]]. The chemical process and details of autolysis were not originally understood but the positive effects of a creamy mouthfeel, breadlike and floral aroma, as well as reduced astringency were noticed early on.<ref name="Oxford pg 399">J. Robinson (ed) ''"The Oxford Companion to Wine"'' Third Edition pg 399 Oxford University Press 2006 ISBN 0-19-860990-6</ref> |
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==History== |
==History== |
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==Influences on the wine== |
==Influences on the wine== |
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The effects of autolysis on wine contributes to a creamy mouthfeel that may make a wine seem to have a [[body (wine)|fuller body]]. The release of enzymes inhibits [[oxidation]] which improves some of the [[aging potential (wine)|aging potential]] of the wine. The mannoproteins improve the overall stability of the proteins in the wine by reducing the amount of [[tartrate]]s that are precipitated out. They may also bind with the [[tannins (wine)|tannin]]s in the wine to reduce the perception of bitterness or astringency in the wine. The increased production of [[amino acid]]s leads to the develop of several flavors associated with premium Champagne including aromas of [[biscuit]]s<ref>Caterer and Hotel Keeper Magazine ''"[http://www.caterersearch.com/Articles/2001/07/26/31586/the-changing-face-of-moet.html The changing face of Moet]"' July 26th, 2001</ref> or [[bread]] [[dough]], [[nut (fruit)|nut]]tiness<ref>Beverage Industry Factsheet ''"[http://www.just-drinks.com/factsheet.aspx?ID=56 Autolysis]"'' Accessed Dec. 20th, 2008</ref> and [[acacia]]. As the wine ages further, more complex notes may develop from the effects of autolysis.<ref name="Oxford pg 54"/> |
The effects of autolysis on wine contributes to a creamy mouthfeel that may make a wine seem to have a [[body (wine)|fuller body]]. The release of enzymes inhibits [[oxidation]] which improves some of the [[aging potential (wine)|aging potential]] of the wine. The mannoproteins improve the overall stability of the proteins in the wine by reducing the amount of [[tartrate]]s that are precipitated out. They may also bind with the [[tannins (wine)|tannin]]s in the wine to reduce the perception of bitterness or astringency in the wine. The increased production of [[amino acid]]s leads to the develop of several flavors associated with premium Champagne including aromas of [[biscuit]]s<ref>Caterer and Hotel Keeper Magazine ''"[http://www.caterersearch.com/Articles/2001/07/26/31586/the-changing-face-of-moet.html The changing face of Moet]"' July 26th, 2001</ref> or [[bread]] [[dough]], [[nut (fruit)|nut]]tiness<ref>Beverage Industry Factsheet ''"[http://www.just-drinks.com/factsheet.aspx?ID=56 Autolysis] {{wayback|url=http://www.just-drinks.com/factsheet.aspx?ID=56 |date=20080327035821 }}"'' Accessed Dec. 20th, 2008</ref> and [[acacia]]. As the wine ages further, more complex notes may develop from the effects of autolysis.<ref name="Oxford pg 54"/> |
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===Potential faults=== |
===Potential faults=== |
Revision as of 05:53, 22 October 2016
![](http://upload.wikimedia.org/wikipedia/commons/thumb/9/98/Cocktail_by_candle_light_1.jpg/200px-Cocktail_by_candle_light_1.jpg)
Autolysis in winemaking relates to the complex chemical reactions that take place when a wine spends time in contact with the lees, or dead yeast cells, after fermentation. While for some wines autolysis is undesirable, it is a vital component in shaping the flavors and mouth feel associated with premium Champagne production.[1][2] The practice of leaving a wine to age on its lees (or sur lie aging) has a long history in winemaking dating back to Roman winemaking. The chemical process and details of autolysis were not originally understood but the positive effects of a creamy mouthfeel, breadlike and floral aroma, as well as reduced astringency were noticed early on.[3]
History
Ancient Roman writers, like Marcus Porcius Cato, observed that wine that was left on its lees (or sediment as they knew it) exhibited different characteristics than wine that was quickly separated from its sediment. While the Romans did not understand the full chemical process or details behind the autolysis that took place, they were able to perceive the results of this autolysis in the creamy mouthfeel, reduced astringency and unique flavors and aromas that developed.[3] With modern day understanding of autolysis, winemaking in the Champagne have strict regulation regarding the time Champagne must spend in contact with its lees in order to receive some benefit from autolysis. Under Appellation d'origine contrôlée (AOC) regulations, wines from Champagne cannot legally be sold until it has gone through autolysis in the bottle for at least 15 months with non-vintage Champagne. Vintage Champagne must have a minimum of 3 years aging with some Champagne houses extending the time for autolysis to nearly 7 years.[4]
Process
![](http://upload.wikimedia.org/wikipedia/commons/thumb/5/54/Undegorgierter_Champagner.jpg/275px-Undegorgierter_Champagner.jpg)
During fermentation, yeast cells convert the sugar in the grape must into ethanol. When the sugar food source for the yeast and necessary nutrients such as nitrogen run out, or the alcohol level of the wine reaches such a point to where it is toxic for the yeast, the cells die and sink to the bottom of the fermentation vessel. These dead cells, or "lees", are normally removed by racking the wine into a clean vessel. If the wine is left in contact with the lees, enzymes start to break the cells down producing mannoproteins (mannose-containing glycoproteins) and polysaccharides that are released into the wine. In sparkling wine production, a wine is made "sparkling" or "bubbly" because a secondary fermentation is introduced when the wine is contained within a sealed wine bottle. During this time the wine is deliberately kept in contact with its lees inside the bottle for a period ranging from a couple months to several years. Studies have shown that the chemical reaction of autolysis, and its impact on the wine, starts to become noticeable after 18 months and will continue to impart traits for at least 5 years. The sparkling wine is eventually separated from its lees through a technique known as riddling and disgorgement.[1]
Influences on the wine
The effects of autolysis on wine contributes to a creamy mouthfeel that may make a wine seem to have a fuller body. The release of enzymes inhibits oxidation which improves some of the aging potential of the wine. The mannoproteins improve the overall stability of the proteins in the wine by reducing the amount of tartrates that are precipitated out. They may also bind with the tannins in the wine to reduce the perception of bitterness or astringency in the wine. The increased production of amino acids leads to the develop of several flavors associated with premium Champagne including aromas of biscuits[5] or bread dough, nuttiness[6] and acacia. As the wine ages further, more complex notes may develop from the effects of autolysis.[1]
Potential faults
If not properly managed, wine faults can potentially develop from autolysis. If the layer of lees begins to exceed 4 inches (10 centimeters), the enzymes released from the process of the yeast digesting themselves creates reducing conditions and promotes the development of hydrogen sulfide and mercaptan odors. The process of stirring the lees or bâttonage can help prevent a thick layer of lees forming and promote a smoother autolysis. Poor hygiene of the winemaking equipment or wine made from grapes that had residue from fungicide can create off odors smelling of sulfide.[3]
See also
References
- ^ a b c J. Robinson (ed) "The Oxford Companion to Wine" Third Edition pg 54 Oxford University Press 2006 ISBN 0-19-860990-6
- ^ Champagne Science "Autolysis - and its effects on Champagne Template:Wayback" Accessed: December 30th, 2008
- ^ a b c J. Robinson (ed) "The Oxford Companion to Wine" Third Edition pg 399 Oxford University Press 2006 ISBN 0-19-860990-6
- ^ K. MacNeil The Wine Bible pg 653 Workman Publishing 2001 ISBN 1-56305-434-5
- ^ Caterer and Hotel Keeper Magazine "The changing face of Moet"' July 26th, 2001
- ^ Beverage Industry Factsheet "Autolysis Template:Wayback" Accessed Dec. 20th, 2008
External links
- M. J. Leroy et al. "Yeast Autolysis During Champagne Aging" American Society for Enology and Viticulture. 41:1:21-28 (1990)
- M. Feuillat & C. Charpentier "Autolysis of Yeasts in Champagne" American Society for Enology and Viticulture Am. J. Enol. Vitic. 33:1:6-13 (1982)