Newlin Grist Mill Research Projects

Experimental Archaeology

As a branch of archaeological study, experimental archaeology replicates or attempts to replicate past processes to understand how things were made, explore how archaeological deposits were created, and study lost production techniques. This includes making tools and objects, recreating manufacturing techniques, and reconstructing structures, complexes, and entire villages. At Newlin Grist Mill, experimental archaeology includes making hand-made brick, bloomery iron, and potash. The challenges associated with experimental archaeology include finding appropriate materials, recreating processes long removed from living memory, and determining how to scale down processes without affecting the outcome. Many of these processes are included as demonstrations during the annual Fall Harvest Festival.

Bloom Iron

Bloomeries were once a common method of manufacturing wrought iron. A small bloomery furnace is charged with alternating layers of charcoal and iron ore. After several hours of firing, the iron ore congeals into a mass called a bloom and the slag is tapped and runs out the bottom. The bloom is removed and then hammered and repeatedly folded until it forms wrought iron.


Newlin Grist Mill has had mixed success with its bloomery operation since beginning to experiment with the process in 2010. We continue to refine our technique. To see images of the iron-making process, watch the slide show.

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Brick Making

In 2012 and 2013, NGM partnered with New Castle Historical Society (NCHS) to reproduce bricks for a hearth restoration. While restoring a chimney in the Historic Amstel House, a fragment of a special hearth brick was discovered. NCHS decided to manufacture replacement bricks for the hearth restoration and approached NGM. The planning team examined sources on brick making tools and techniques and spoke with individuals involved in brick making projects.


During the first two seasons, the team of staff and volunteers learned many lessons about processing and handling the clay, working with moisture content, and firing the bricks. To see images of the brick making process, watch the slide show.

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Potash Manufacturing

Potash was an important ingredient in many manufacturing processes including glass, soap, and pearlash. During the 18th century, England had a shortage of the much used material and looked to its colonies in North America. Potash is created from hardwood ash and colonists were clearing large tracts of land each year. Several pamphlets were printed instructing colonists how to make potash. Using these colonial instructions, Newlin Grist Mill with the assistance of historian Patrick Harshbarger has tried to recreate the process.


Hardwood trees were burned in the manner instructed to create the most ash and then the ash was boiled to reduce into potash. To see images of the potash manufacturing process, watch the slide show.

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Message to Our Community


In light of current conditions, Newlin Grist Mill continues to be closed as follows:

  • The NGM Visitor Center, Archive, Blacksmith Shop, Millwright Shop, and public restrooms remain closed;

  • All tours, programs and events have been postponed or cancelled during this period;

  • Pond Fishing will remain closed until further notice;

  • Rentals are being cancelled for this period of time;

  • There will be no Volunteer Wednesday Workdays;

  • The trails will remain open, but parking is limited; and we ask that everyone be mindful of social distancing when on the property.

Decisions concerning additional closings will follow based on the developing situation. Please check back for updates.

While the trails at Newlin Grist Mill remain accessible while the site is closed due to the COVID-19 pandemic, we do want to remind everyone of a few things:

  • Continue to observe proper social distancing when you are on the trails. If you are ill or have been around anyone who is ill or has been exposed to the virus, please remain at home. If you arrive and find that the parking lot is crowded, please postpone your visit to another time.  

  • Please remember that all dogs must be on a leash that is held securely by the owner at all times. This is a township law, and it is to protect the health and safety of all park visitors (human and canine) and the wildlife in the park.

  • The park contains unique habitats that are home to sensitive plants and animals, some of which are being monitored through ongoing scientific surveys.  Please stay on the trails to avoid disturbances (wading, dip netting, collecting, rock throwing etc.) that could damage wildlife and vegetation. 

  • Remember that collecting of any kind, including plants and animals, is prohibited in the park.

We appreciate your understanding and support during this challenging time.

Newlin Grist Mill   l  219 South Cheyney Road   l  Glen Mills, PA 19342   l   610.459.2359   l   © Copyright 2014-2015 Newlin Grist Mill. All rights reserved.