Maple syrup is one of our oldest agriculture crops and is one that is solely North American. Iowa is not generally thought of as being a maple syrup producing state, but it does have a few commercial producers in the northeastern part of the state. Currently the local market for maple syrup and candies is greater than the supply.
A potential producer of maple syrup must carefully analyze their individual situation before embarking on this labor intensive enterprise. One must have maple species (sugar maple, black maple, silver maple or boxelder) at least ten inches in diameter, the resources to invest in the necessary equipment and supplies, and the large amount of time and labor required by this enterprise.
Trees must be at least ten inches in diameter to tap. Use one tap for trees 10-15 inches in diameter, two taps for 16-20 inch trees, three taps for 21-25 inch trees and, no more than four taps for trees over 25 inches in diameter. Trees should be tapped before the sap begins to run in the trees. Sap collection usually begins in Iowa in late February or early March and lasts for approximately three weeks.
Special equipment required to collect sap includes: brace and bit for boring the holes in the trees, spiles to transfer the sap from the tree to buckets or bags, buckets or sap bags for collection, a system to transport the sap to the evaporator such as a bulk tank or plastic tubing with pumps, and storage facilities for the sap until it is processed into syrup.
Maple sap averages around 2% sugar content; maple syrup is approximately 66% sugar. Actual sugar content of sap varies widely from tree to tree and from
season to season, but maple sap at 2% sugar content requires 43 gallons of sap to produce a gallon of syrup. This concentration of sap to syrup is accomplished by boiling the sap in an "evaporator". Simple evaporators are open pans over a heat source or more expensive and complex systems for continuous production of syrup.
Minimum equipment required for evaporation include the flat evaporator pan with a source of heat (usually wood or LP gas), filters, sap and syrup hydrometers for determining syrup and sap density, bottles, seals and labels. Maple syrup production is very labor intensive. For a small operation of 50 taps, 150-200 hours of labor will be required.
Yield of syrup varies from season to season and from tree to tree. In Iowa the average yield of syrup per tap varies from one-half to one quart. In addition, there are some quality differences between species (sugar and black maple are preferred) and quality variation during the sap flow season (late sap may be less desirable). Local markets will probably not make a distinction between syrup from different species. Most producers sell their product locally, but some wholesale opportunities for large scale production exist in both Minnesota and Wisconsin for syrup produced in Iowa.
Good management is necessary to both increase profitability and reduce risks. Excellent sanitary practices are a must to produce a high quality product and avoid potential liability claims. Care in the boiling and finishing processes is necessary to avoid scorching or imparting a undesirable flavor to the final product. Minimizing the time period between sap collection and boiling will improve syrup quality and minimize losses due to spoilage. Because this is a food product, licensing and permits through the Iowa Department of Agriculture may be required.
Both sap yield and sugar content can be improved through sugar bush management. Forestry practices which promote crown development will increase the yield and sugar content.