A cool place in 18th century New York: Excavating a cold storage shed on the Tweed Courthouse grounds

Now that spring is in the air, the City Museum’s Archaeology Project is ready to answer your warm-weather questions!  Obviously, the most pressing question on readers’ minds is: How did New Yorkers in the late 18th century keep their food cold?

New Yorkers would have created a dedicated “ice box” room, or shed, to store perishable foods. Below-ground spaces such as dug-out root cellars or “finished” cellars stay cool naturally although ice would also be used, if available. Hartgen Archeological Associates, Inc. excavated one such outbuilding (pictured below) in 2001.  These excavations were conducted in today’s City Hall Park, around the Tweed Courthouse, one of the most famous municipal buildings in lower Manhattan. The Courthouse was built between 1861 and 1881 in the northern section of City Hall Park along the south side of Chambers Street; City Hall Park, however, has been a center of civic activity in New York City for hundreds of years and many different structures stood in that spot over time.

One of the oldest structures in City Hall Park is known as the Upper Barracks (1735-1790).  The Upper Barracks was constructed by the British military and housed hundreds of British soldiers during the Revolutionary War. The archaeological remains of the Upper Barracks is partially located under the present footprint of Tweed Court House.

This cold storage shed built during the 18th century was discovered at Tweed Courthouse in 2001 by Hartgen Archaeological Associates, Inc.  Thick cut-stone exterior walls with a brick-lined interior helped to keep the building cool and dry.  Click the image to take a closer look at the walls. Image courtesy of NYC Landmarks Preservation Commission.

Archaeologists believe the architectural remains pictured above represent an 18th century cold storage shed associated with the Upper Barracks. The thick walls, the depth of the structure, and architectural elements such as a floor drain are consistent with other cold storage spaces from the 18th century. The size of the bricks (8¼-8½ inches long, 4 inches wide, and 1¾-2 inches thick) indicate they were produced before the Revolutionary War.  The bricks could have been removed from an even older structure and reused to build the shed.

A brick from the cold storage shed. Some mortar remains attached to the brick’s surface.

The mortar helped archaeologists link this structure to the Upper Barracks.  The mortar was typical of the later colonial period, sandy in texture with chunks of lime.  The chunks of lime, however, are relatively large, which provides a clue about who might have built the shed.

Experts at the Colonial Williamsburg Brickyard study and recreate historical masonry. They successfully burned oyster shells to produce lime in 2009. Please follow this link to learn more. Image from the Colonial Williamsburg Foundation’s Richard Charlton’s Coffeehouse blog (accessed April 30, 2015)

Lime derived from limestone had to be imported from quarries, which was costly during the colonial period.  Lime was also made locally by burning oyster shells, but this process required a lot of labor and resources.

Because lime was expensive it was often used sparingly, so the presence of large chunks of lime in the shed’s mortar suggests that it was built by someone very wealthy or by order of the government with generous official funding. This supports the conclusion that the shed was probably a part of the Upper Barracks, since the British military had access to the necessary resources and labor to obtain plenty of lime for the mortar.

Experts at the Colonial Williamsburg Brickyard produce lime using 18th century techniques. Please follow this link to learn more. Image from the Colonial Williamsburg Foundation’s Richard Charlton’s Coffeehouse blog (accessed April 30, 2015)

Artifacts found inside the shed (pictured below) are also consistent with the period of the Upper Barracks.  A range of utilitarian ceramics, animal bones, and oyster shells were excavated along with fragments of fine 18th century teawares.

Fragments of decorated ceramics excavated from inside the cold storage shed.

Artifacts excavated from inside the cold storage shed.

These artifacts, and many more, are being cataloged and digitized at the Museum of the City of New York as preparation for public access and long term care at the Landmarks Preservation Commission Archaeological Repository. Research inquiries may be directed to archaeology@lpc.nyc.gov

And, to learn more about landmarked sites in New York City, such as the Tweed Courthouse, visit the City Museum’s exhibition Saving Place: 50 Years of New York City Landmarks, on view through September 13, 2015.

.