Champagne and Coffee

The reason may very have similar reasons to that of an unlikely product: coffee.

Champagne owes its sparkle due to the production of carbon dioxide (CO₂) during the secondary fermentation of wine in the reaction below: 

C₆H₁₂O₆ (s)------fermentation---------->2CH₃CH₂OH (l)+ 2CO₂ (gas)

The reaction which states that during fermentation one molecule of sugar (C₆H₁₂O₆) will convert into two moles of ethanol (CH₃CH₂OH) and two moles of gaseous carbon dioxide (CO₂).

It is this CO₂ that builds up and ultimately creates the pressure build up inside the bottle of champagne. Its also the reason we hear a loud "pop" that we've all come to appreciate during festive activities. 

Of course there are a number of factors that affect the reaction, but depending on the extent of fermentation the final pressure inside a bottle can several times that of atmospheric pressure. 

In much the same way carbon dioxide is produced in coffee, but not during fermentation, but rather during roasting through a series of complex reactions beginning at 302°F (150°C). And just like in Champagne, the final level production of CO₂ will ultimately depend on the extent of the roast as well other factors.

Coincidentally the pressure inside a bottle of champagne and a roasted coffee bean are about the same. 

So the next time you make a toast you have carbon dioxide to thank for in that sparkling glass of bubbly!