India, Sept. 3 -- One of the pleasures of studying the history and culture of food is discovering where a single line in an old book, newspaper, or a recipe can lead. A passing reference to a dish, an ingredient or even a particular fruit can open up a much larger story, taking you across kitchens, gardens, markets, and continents.

"Only fit for tarts." That was how Robert Riddell described the green grapes appearing in Poona's markets in September in his "A Manual of Gardening for Western India" (1842). They were the second crop of the vine; the first appeared between January and March. Unlike the sweet grapes of the principal season, these were sour. They were abundant, but of little value as table fruit.

Riddell's description hints a...