Thus, massive icehouses - several stories tall and capable of holding up to 28,000 tons of ice - were built along the more pristine waterways, snaking from Schwenksville through lower Lehigh County, in the Upper Perkiomen Valley.
The location afforded easy access to Philadelphia by rail, and many of the icehouses employed city dwellers during ice-harvesting season. That led to the growth of hotels and restaurants to serve those workers, many of whom traveled there by train, Roeder said.
The workers, along with farmers looking for seasonal work, built huge dams in creeks. In turn, the dams formed ponds that filled and froze; one, in fact, stretched across 46 acres.
To increase production, workers would sometimes drill holes in the ice to allow more water to rise and freeze.
When enough ice had formed, crews used crowbars and saws to separate blocks of ice that would be floated downstream to the various icehouses.
There, workers with large poles corralled the blocks to inclines, where they were packed together in the warehouses, with layers of sawdust in between to keep them from melding together.
As temperatures rose, skeleton crews shipped ice down to Philadelphia on an as-needed basis, and a single ice shipment could fill eight to 12 boxcars, Roeder said.
Because of the sawdust insulation, the icehouses could supply ice throughout the summer, he added.
Today, almost nothing remains. By the 1930s, modern refrigeration had made the large icehouses unnecessary, and they were all dismantled or destroyed.
The region still isn't a pushover when it comes to ice manufacturing, however. Now, the region's ice manufacturing is geared toward selling to convenience stores, with out-of-town companies buying out local ice-making businesses, according to Jason Flexer.
Flexer, who gives presentations with Roeder on the history of ice, sold his ice business, Nolt's Ice Co., to Home City Ice of Ohio in October.
"I kind of stumbled into it," he said of the business, where he started working out of high school a couple of decades ago.
Nationally, ice companies these days generate $1.8 billion in revenue. Said Flexer: "Most people don't realize how big the ice business is."
Contact staff writer Anthony Campisi at 215-854-5015, acampisi@phillynews.com, or @campisia on Twitter.
