Maple syrup is made from just one ingredient, maple sap, which magically flows from trees in late winter. It takes specific weather conditions this time of year to create sap flow, caused by nighttime temperatures below freezing followed by daytime temperatures above freezing (ideally 20⁰F at night and 40⁰F during daytime). The sugar containing elixir that flows from maple trees can then be boiled down to syrup or even further for granulated sugar.
Humans have been collecting maple sap to create sugar for thousands of years on this continent. Native Americans, with their intimate connection to the natural world, were the first to key in on this bountiful resource. Prior to Europe influence and trade, sap was their only source of sweetener.
To harvest sap, Native Americans first used stone tools to make horizontal gashes in the tree trunk. A piece of material (typically birch bark or splines made from cedar or pine) was pounded into the lower portion of the gash, concentrating sap flow to a single point. Collection containers were typically fashioned from birchbark by heating the bark over a fire to make it pliable, then bending it and shaping it into a suitable receptacle. These vessels were held into shape with simple sewing stiches using basswood fiber or spruce roots and placed underneath the dripping sap to collect it.
Sap boiling was also accomplished using birchbark containers or wooden troughs made from sections of hollowed out logs. Sap was collected and poured into these larger-sized containers and extremely hot rocks taken directly from a fire were placed in the container of sap. Rocks were replaced frequently, evaporating off water slowly as they cooled in the sap. To streamline the process, sap was allowed to freeze overnight when temperatures were cold enough, locking up water as ice that could be removed the next morning.
Upon contact with early European settlers, Native Americans gained access to metal boiling pots and further streamlined the process. Settlers learned quickly from the indigenous tribes and began steady production of maple sugar for use as a sweetener. Throughout the 17th century, maple sap harvesting increased as the settlers added the innovative practice of drilling tapholes with an auger. During the late 17th and 18th centuries, maple sap was the primary source of sweetener in North America since more costly cane sugar had to be imported from the Caribbean.
Maple syrup production technology has grown immensely over the years from the birch bark buckets and boiling hot stones of Native Americans to modern facilities that maximize efficiency of the process. Today it is possible to remove a significant portion of the water through a reverse osmosis process, which results in about 8-9% sugar in the concentrated sap. This process has improved the energy efficiency of syrup production since it reduces boiling time, which is the most energy intensive part of the process.
Interestingly, maple is not the only genus of tree with harvestable sap, although the sugar maple (Acer succharum) has the highest sugar content in its sap, at about 2 percent sugar. Sap from any of our other native maple trees can also produce syrup, but at greater energy expenditure to concentrate the sugars since sugar content is lower and more water must be boiled off. Other genera that have been regularly harvested for syrup are Juglans (walnut), Carya (hickory), and Betula (birch), but many other native deciduous hardwood trees also yield sap with a useable sugar content.
Throughout history, the harvesting of maple sap has been late winter ritual on this continent. There is something remarkable about the simple process of collecting and boiling a native-tree-produced product, like maple sap. For the past 5 years, I have harvested sap from trees on our property to make maple syrup, only being able to produce an entire year’s supply once, but we still tap trees each year as it is a fun and interesting family activity. Although the 2018 sap run is waning, I encourage you to look around your property this year for a few maples to tap next winter. The rewards can be quite sweet!