Wisconsin Energy Efficiency and Renewable Energy Resource

Maple Syrup Production

In 2003 Wisconsin produced approximately 76,000 gallons of maple syrup, according to the Wisconsin Agricultural Statistics, from 350 producers. Production has ranged from a high of 87,000 in 1997 to a low of 65,000 gallons in 2000 during the last 7 years with an average of 74,000 gallons produced. According to the Ministry of Agriculture and Food, Ontario, Canada, it takes between 2.7 to 3.4 gallons of fuel oil to produce 1 gallon of maple syrup or between 4 to 500,000 BTUs per gallon. Based on Wisconsin's average production of 74,000 gallons, it would require 31 billion BTUs of energy to produce or the equivalent of 225,000 gallons of heating oil. Several different fuel sources are use for processing including wood, heating oil, propane and natural gas. According to the summary of a 2003 survey of Wisconsin Producers, the breakdown of primary fuel types was 45% wood, 49% fuel oil, 4% natural gas and 2% Propane. Wisconsin is ranked a distant 4th in maple syrup production in 2003 behind Vermont, New York and Maine, producing 6% of the U.S. production. Energy is a major component in the cost of production, accounting for 25% of the processing costs and 14% of the total cost (1994).

There are several technologies and devices that can reduce the energy costs in producing maple syrup.

• Evaporator and burner maintenance - Typical maintenance issues include cleaning nozzles, insulating fireboxes, correct size nozzles, cleaning build up off of pans, proper air mixture.
• Pre-heater - A Sap pre-heater increases the efficiency of an open pan evaporator by using the steam coming off the evaporator pan to preheat the sap before it enters the pan. The heat exchanger is typically copper tubing that is suspended under a hood over the evaporator pan. The steam condenses on the cooler pipe surface, transferring heat to the sap. A drip pan catches the condensate and drains it away from the evaporator pan. A properly sized pre-heater will commonly increase the efficiency of an evaporator by 15%.
• Piggy-back or economizer units - These units are a combination pre-heater and evaporator. The unit sets over the evaporator pan and uses steam from the evaporator pan to pre-heat the sap to as high as 200°F. From manufacturer's literature, it appears to increase production by 60% to 65% with no increase in energy usage.
• Reverse osmosis - Reverse Osmosis systems have been used commercially in maple syrup production since the mid 1970's. The technology works the same as desalination of salt water except water is the by-product and the sugar concentrated sap is the product. Reverse osmosis can remove 75% of the water from the sap, reducing energy usage by 70% over open pan evaporation. The equipment is pricey and is therefore only economical on larger operations but it can reduce energy use to about a gallon of heating oil per gallon of syrup produced.
• Evaporator designs - New designs of evaporators incorporate pre-heaters and economizer units as well as preheating of fuel oil and air for more efficient combustion, air tight and insulated combustion chamber and combustion chambers design to maximize the heat transfer rate.

Energy Efficiency Studies

In a 1988 study, 15 sugaring operations were provided energy audits with 11 of the operations determine to have energy conservation opportunities that would reduce energy costs an average of 31%. There were eight recommendations to increase burner efficiency, four to install or upgrade a sap pre-heater, 3 to install economizer units and one recommendation to install a reverse osmosis unit. The paybacks ranged from 0.3 to 7.4 years. Increasing burner efficiency and installing a preheater had the lowest cost and fastest payback. A 2003 survey reported wood fuel efficiency of producing a gallon of maple syrup ranged from 170,000 BTU for a producer that used a preheater, economizer and a reverse osmosis unit to 5,343,000 BTU per gallon for a hobbyist. Non-wood fuels ranged from 133,250 BTU per gallon for a producer using a reverse osmosis unit to 454,000 BTU. Large producers were more efficient as well as those using non-wood fuels. Large producers were more apt to use some type of energy efficiency equipment.

"Maple Syrup Production Energy Use Survey Summary- 2003", Scott Sanford, University of Wisconsin, 2003.

Links

1. General Information
• Wisconsin Maple Syrup Producers Association web site - http://www.wismaple.org
• Cornell Sugar Maple Research and Extension Program web site - http://maple.dnr.cornell.edu/
• Hobby Maple Syrup Production, Randall Heiligmann, Fact Sheet F-36-02, Ohio State University, 2002. http://ohioline.osu.edu/for-fact/pdf/0036.pdf
• North American Maple Syrup Producers Manual http://extension.unh.edu
• Maple Syrup Quality Control Manual, Kathryn Hopkins, Bulletin 7038, University of Maine Cooperative Extension, 2002. http://www.umext.maine.edu/onlinepubs/PDFpubs/7038.pdf
• University of Vermont Maple Pages - http://www.uvm.edu/~uvmaple/
• Commonly Asked Questions about Maple Syrup in Ontario - http://www.omafra.gov.on.ca/english/crops/facts/maple.htm
2. Equipment Manufacturers
• Dominion & Grinn Inc. - http://www.domgrimm.com/
• Leader Evaporator Co. - http://www.leaderevaporator.com/
• Les Équipements d'Érablière CDL Inc. - http://www.cdl-dallaire.com/
3. Equipment Suppliers
• Anderson's Maple Syrup Inc., Cumberland, WI - Phone: 715-822-8512, http://www.andersonsmaplesyrup.com
• James Adamski - Antigo, WI - Phone: 715-623-6853
• Kickapoo Gold, LLC, Westby, WI - Phone: 608-634-4155, http://www.kickapoogold.com
• Maple Hollow, Merrill, WI - http://www.MapleHollowSyrup.com
• Roth Sugar Bush, Cadott, WI - Phone: 715-289-3820, http://www.rothsugarbush.com
• GBM, LLC, Holcombe, WI - Phone: 715-447-8440, http://www.gbmllc.com

If you have information you think would be useful to this site please contact
Scott Sanford, Senior Outreach Specialist, University of Wisconsin, sasanford@wisc.edu.