Thank you Ben Baranowski , John Cronin , Eleni Gaves , and Westley Satterwhite for your responses last week in the discussion on phylloxera!
This week: Madeira
Describe how the process of Madeira was discovered and how that is imitated today.
Short version: Madeira was discovered via the fortified wine being shipped across the Atlantic and being heated in barrels in the hull of the ships as they travelled through warm tropical regions, then cooling as travel led them through cooler areas. Today, the wine is heated and cooled for periods of time before bottling, which creates a remarkably stable product virtually resistant to oxidation, as the heating process has already oxidised the wine, providing the characteristic nutty and caramel toffee flavors.
Great historical explanation by Justin!
The main two modern heating and oxidizing techniques--which typically correlate directly with the quality of the finished wine--are the Estufagem and Cantiero processes. In the Estufagem process, base wines are heated in stainless steel vats with circulating hot water. This 90 day minimum process will end with wines being transferred to oak. This can result in wines that are more austere with more burnt caramel flavors and aromas from rapid oxidation. Notably, fortification happens AFTER time in the estufa. In the Cantiero process, the wines get to oxidize quite a while longer. Winemakers drag barrels and casks up to attics--or even the roof!!--to expose them to the warmth of the sun. This oxidative process takes two and sometimes up to twenty years to complete! Cantiero oxidation is generally reserved for the best madieras, which affords smoother, more balanced flavors and aromas.
As with 99% of other winemaking, if you want a generally better product, get ready to spend time and money on it!