Yankee Hi-Tec Helps feed the UNION ARMY Isaac Winslow of Portland, Maine had been engaged in the whaling business when in 1839 he first began experimenting with canning as a method of food preservation. It wasn’t until 1852 though, that he filed for a patent to protect his process. His request would not be granted until ten years later in 1862. Yankee persistence would pay off however as the business benefited greatly from large Civil War time contracts with the Union Army. Winslow Packing Co. became a world leader in the fledgling canning industry. Brother Nathan Winslow’s tinsmith & stove shop on Front Street in Portland, Maine clearly played a role in expansion as sheet metal stoves and experienced tinsmiths were needed to process vegetables and to fabricate and vacuum seal each full can with the telltale spot of lead solder that Civil War collectors look for as period identification. Crews of tinsmiths such as those shown in the period tintype photo above, continued to hand fabricate and seal tin cans until about 1870.