The ice trade
By the 1830s ice had become a very profitable American export. In 1833 American ice was being shipped as far as Calcutta, when the Tuscany, which had sailed from Boston on May 12, reached the mouth of the Ganges on September 5. Calcutta, one of the hottest and most humid cities on earth, and then the capital of British India, was ninety miles up the Hooghly River, and the population awaited the ice with breathless anticipation. The India Gazette demanded that the ice be admitted duty free and that permission be granted to unload the ice in the cool of the evening. Authorities quickly granted the demands. Frederic Tudor managed to get about a hundred tons of ice to Calcutta, and the British there gratefully bought it all at a profit for the American investors of about $10,000.
By the 1850s American ice was being exported regularly to nearly all tropical ports, including Rio de Janeiro, Bombay, Madras, Hong Kong, and Batavia (now Jakarta). In 1847 about twenty-three thousand tons of ice was shipped out of Boston to foreign ports on ninety-five ships, while nearly fifty-two thousand tons was shipped to southern American ports.
That is from John Steele Gordon’s An Empire of Wealth: The Epic History of American Power. This new book is the best single volume treatment of American economic history I have read, highly recommended. Here is a review, and note that the book’s perspective is Hamiltonian, not Jeffersonian.
And here is more on the ice trade. Here are good photos of the Norwegian ice trade, and yes they were exporters not importers.