Changes

Young finished champagne and sparkling wines produced according to the ''méthode traditionnelle'' process, which involves carbonating the champagne with sugar for 15 months and then disgorging them and corking them, begin with a CO² concentration of around 11-12 g/L (~6 volumes), while sparkling wines that are 5 years old and 10 years old have been found to have a much lower concentration of CO² at around 6-8 g/L (~3-4 volumes) <ref>[https://www.sciencedirect.com/science/article/pii/S000326700901349X?via%3Dihub Gérard Liger-Belair, Sandra Villaume, Clara Cilindre, Philippe Jeandet. 2010.]</ref><refname="Liger-Belair_2011">[https://pubs.acs.org/doi/abs/10.1021/jf104675s Losses of Dissolved CO2 Through the Cork Stopper during Champagne Aging: Toward a Multiparameter Modeling. Gérard Liger-Belair and Sandra Villaume. 2011.]</ref>. The gradual loss of carbonation in sparkling wines has been attributed to the porous nature of corks allowing for the slow diffusion of gasses through them, which is highly variable based on the density of the cork <ref>[https://www.ncbi.nlm.nih.gov/pubmed/19215133 Kinetics of CO(2) fluxes outgassing from champagne glasses in tasting conditions: the role of temperature. Liger-Belair G1, Villaume S, Cilindre C, Jeandet P. 2009.]</ref><ref>[https://www.sciencedirect.com/science/article/pii/S0003267009013981?via%3Dihub#tbl1 Foaming properties of various Champagne wines depending on several parameters: Grape variety, aging, protein and CO2 content. Clara Cilindrea, Gérard Liger-Belair, Sandra Villaume, Philippe Jeandet, Richard Marchal. 2010.]</ref>, as well as the interface between the cork and the neck of the bottle <ref name="Liger-Belair_2011" />. An interesting observation is that there wasn't a large difference in carbonation loss between 5-year-old sparkling wines and 10-year-old sparkling wines, indicating that the loss of carbonation could greatly slow down once the liquid inside reaches around 3-4 volumes of CO². The construction of the cork itself is a variable that makes it difficult to predict the exact rate of CO² loss. Corks are composed of two distinct parts: the mushroom of the cork is made up of agglomerated cork small granules, while the foot of the cork is made up of two large cork slices. This lower part is made up of several [https://en.wikipedia.org/wiki/Lenticel lenticels], which are parts of the plant that allow gasses to flow in and out of the plant. These lenticels vary from cork to cork. Nevertheless, a model has been proposed by Liger-Belair et al. that estimates the amount of CO² loss over time. In this model, two other variables have been identified as playing a large role in how much CO² is lost: storage temperature and bottle size. The warmer the storage temperature, the faster the rate is of losing of CO², and the larger the bottle volume the slower the rate is of losing CO². Below are some estimated CO² levels in g/L and then converted to volumes in parenthesis at various points in time <ref name="Liger-Belair_2011" />: {| class="wikitable sortable"|-! Storage Temp °C <ref name="Liger-Belair_2011" /> !! CO² g/L (vols) at Year 0 !! CO² g/L (vols) at Year 5 !! CO² g/L (vols) at Year 10 !! CO² g/L (vols) at Year 15 !! CO² g/L (vols) at Year 20|-| 4 || 12 (6) || 9.5 (4.75) || 7.5 (3.75) || 6 (3) || 5 (2.5)|-| 12 || 12 (6) || 9 (4.5) || 6.5 (3.25) || 5 (2.5) || 4 (2)|-| 20 || 12 (6) || 8 (4) || 5.5 (2.75) || 4 (2) || 2.5 (1.25)|-|} {| class="wikitable sortable"|-! Bottle Size and stored at 12 °C <ref name="Liger-Belair_2011" /> !! CO² g/L (vols) at Year 0 !! CO² g/L (vols) at Year 5 !! CO² g/L (vols) at Year 10 !! CO² g/L (vols) at Year 15 !! CO² g/L (vols) at Year 20|-| 1.5 L (Magnum) || 12 (6) || 10 (5) || 8.5 (4.25) || 7 (3.5) || 6 (3)|-| 750 mL (Standard) || 12 (6) || 9 (4.5) || 6.5 (3.25) || 5 (2.5) || 4 (2)|-| 375 mL (Half Bottle) || 12 (6) || 7.5 (3.75) || 5 (2.5) || 3.5 (1.75) || 2 (1)|-|} The above tables show a significant decrease over the first 5 years, and then a gradual decrease over the decades. As the pressure decreases inside the bottle, the rate of CO² loss slows down. This data may or may not accurately reflect highly carbonated sour beer. Other factors in sour beer that do not apply to sparkling wine and Champagne include living ''Brettanomyces'' which could continue to slowly release CO² by fermenting long chain sugars, although this could also be an insignificant amount if the beer was aged for a long time before packaging (see [[Packaging#Final_Gravity|Final Gravity]]).