I haven't read the book, but it sounds like he was adding aging to what was already done!

Madeira is a specific type of fortified wine from the Madeira Islands (owned by Portugal, between Europe and Africa) that was extremely popular in colonial and post-colonial America (the colonies consumed up to 95% of all production at one point). The key to making it was a combination of aging and heat that was discovered by accident.

The Madeira Islands were a major port of call for ships traveling across the Atlantic or around Africa to reach the East Indies, so many ships would stop there and restock with fortified wine similar to port (adding a little distilled alcohol would help preserve the wine over a long voyage). When a shipment of undrank wine was returned after the voyage, it was discovered that the long period of aging in the hot holds of the ship had created a dark, sweet, intensely flavorful oxidized product.

Initially the popular form of Madeira was vinho da roda which had made a round trip from the islands and back, but this was very costly. It was found that the aging could be imitated with applied heat at the winery, such as placing the wine in special rooms exposed to the sun. Sending a shipment of Madeira around the world twice would indeed be an extravagant way of showing off his wealth, further aging his wine at great personal cost to create a very valuable product just for himself.

The golden age of Madeira ended in the second half of the 20th century. The phylloxera epidemic that nearly destroyed wine production in Europe reached the island and most of the vineyards were uprooted for sugarcane plantations. Madeira also became less necessary as a port of call as technology allowed ships to travel farther and planes to take over, which led to Madeira becoming a cheap product on par with cooking sherry.

Fortunately, Bartholomew Broadbent was hired to revitalize the Madeira industry and the classic product is back on the market. Find yourself some Broadbent Malmsey if you want a taste of what the Founding Fathers enjoyed.