Extension Associate Professor: Agricultural Engineering

Chris Callahan is the Extension Associate Professor of Agricultural Engineering at the University of Vermont. His work focuses on the application of the engineering practice to food systems. Specific engagement is with food producers, processors, and distributors to improve efficiency, quality, safety and cost control through integration of technology, systems integration and process controls. Research and educational programming includes the following:

  • Post-harvest practices and storage - water management, environmental control, drying systems, humidification systems, refrigeration systems
  • Protected culture and covered growing systems - greenhouses, high tunnels
  • Energy use in the food system - farm-based biofuels, renewable energy systems, energy efficiency measures
  • Development of specialized equipment - hops harvesting, hops drying, meat curing, computer aided field operations

This work has led to a number of technical innovations that are either in application for patent or have been made available as open-source for public adoption.


C. Callahan. Electronic Psychrometer and/or Humidistat with Low Temperature and High Humidity Capability. United States Patent #9689819. June 27, 2017.

C. Callahan, S. Sawyer, E. Kahler. Final Report: The Vermont Bioenergy Initiative. A Decade of Local Production for Local Use. DOE Award #GO88182. September 2016. [NR]

Sawyer, S., Garza, E., DePillis, A., Vandette, J., and Callahan, C. Vermont Farm to Plate Strategic Plan: Chapter 4. Section 6. Food System Energy Issues. Vermont Sustainable Jobs Fund. 2016. [R]

V. Grubinger, C. Callahan, J. Faulkner, R. Achilles, and J. Buckley.  Guidance on Wash Water Discharge from Vegetable Pack Sheds - Advice on System Design. UVM Extension with Vermont Agency of Agriculture, Food and Markets. May 16, 2016. [NR]

C. Callahan. Advanced Electronic Psychrometer for Improved Measurement and Control of Humidity in Real-Time. 2015 ASABE Annual Meeting. New Orleans, LA. July 2015. [NR]

C. Callahan. On-Farm Biodiesel in Vermont: A Decade of Learning. (A Techno-Economic Model). 2015 ASABE Annual Meeting. New Orleans, LA. July 2015. [NR]

C. Callahan. An Update on Solid Grass Biomass Fuels in Vermont. UVM Extension with Funding from The Vermont Bioenergy Initiative. April 18, 2016. [R]

C. Callahan. Biomass Boiler Installation at The Vermont Farmers Food Center. UVM Extension with Funding from The Vermont Bioenergy Initiative. April 9, 2016. [NR]

C. Callahan. Final Report: Food Storage Curriculum for Farmers and Processors - SARE ONE13-076. December 31, 2015. [NR]

C. Callahan. Final Report: Toward a Regional Postharvest Research and Extension Center for the Northeast [Project #2014-2]. December 18, 2015. [NR]

V. Grubinger and C. Callahan. Final Report: Heating Vermont Greenhouses with Biomass. High Meadows Fund Gift Funding. (Additional project scope supported by Green Mountain Power CEED Funding.) September 4, 2015. [NR]

V. Grubinger and C. Callahan. Final Report: Improving and Expanding Winter Crop Storage in Vermont. Working Lands Service Provider Grant. August 27, 2015. [NR]

H. Darby and C. Callahan. Chapter: “On-farm Oil-based Biodiesel Production” in Biomass to Biofuels. A. Dahiya, editor. Elsevier. 2015. [B]

C. Callahan and H. Darby. A Mobile Hops Harvester: User-based, Public Domain Design and Shared Infrastructure in an Emerging Agricultural Sector. 2014 ASABE Annual Meeting. Montreal, QC. July 2014. [NR]

C. Callahan and V. Grubinger. Remote Monitoring for Improved Winter Storage Crop Quality. 2014 ASABE Annual Meeting. Montreal, QC. July 2014. [NR]

C. Callahan. How and Why a Small Digester Works. 2008 USDA SARE National Meeting. Kansas City, MO. March 2008. [NR]

Associations and Affiliations

chris callahan

Areas of Expertise and/or Research

  • Systems and process engineering
  • Thermal processes and heat transfer
  • Greenhouse energy efficiency and renewable energy
  • Oilseed processing and farm-scale biodiesel production
  • Harvest and post-harvest processing equipment and systems
Suggested Topics for Comment

Biodiesel, biomass heating, controls, greenhouse energy, hops processing, oilseeds, post-harvest, refrigeration


  • PE (Mechanical)
  • MBA, Rensselaer Polytechnic Institute
  • BSME, Rensselaer Polytechnic Institute


  • 802-656-7501
Office Location:

310 Main Street, Second Floor, Bennington, VT 05201-3045 (P.O. Box 559)