The process of removing (disgorging) sediment from traditional method sparkling wines. Results in a slight loss of volume that needs to be topped up with a dosage before final corking.
For such a simple product, wine sure can get complicated. Take, for example, the exquisite sparkling wines of Champagne and elsewhere. The two main by-products of fermentation are alcohol and carbon dioxide. Under normal circumstances, we want to keep the alcohol and get rid of the CO2, except in the case of sparkling wines. Then we want to preserve the CO2. It is, after all, the quality that makes sparkling wines both special and expensive.
The objective when making sparkling wine is to retain as much of the CO2 as possible while producing a delectable and distinctive wine. The problem is that, when sparkling wine goes through its second fermentation, everything is trapped in the bottle. As the yeast works to produce additional alcohol and carbon dioxide bubbles, it also produces sediment. Now, there’s nothing wrong with letting the sediment stay in the bottle, but it can be rather unappetizing. Better to get rid of it. But that’s not so simple a task.
Traditional or champagne method sparkling wines go through a number of interesting processes. First, a second fermentation is induced in the bottle by adding yeast and sugar to a base wine. That brew is allowed for work for up to several years. Lying peacefully on their sides, the bottles go through an almost magical transformation, with the spent yeast – the lees – giving the wine unique toasty, biscuity qualities. Finally, steps are taken to remove the lees from the bottles. The process is call riddling, and it can be performed by hand or by a machine called a gyro-palette.
The Widow Cliquot perfected the technique of preparing a champagne bottle for dégourgement by placing the bottles in an A-frame rack. Riddlers spend their day shaking and rotating the bottles in the rack, gradually working the sediment into the neck of the bottle over several months. Eventually the bottles are standing vertically in the rack, with the neck pointing downward, ready to have the sediment removed. The bottle neck is set in a bath of iced brine. This freezes a small amount of the wine along with a plug of sediment. It’s then a small job to lift the bottle from the brine solution, pop the cap, and expel the plug. All that remains is to top up the bottle to replace the lost liquid, and then cork it. (By the way, this is the process that begat the rather large foil that is found atop champagne and sparkling wine bottles. Its original purpose was to disguised the fill line so the buyer is not aware that there could be a bit of variation here.)