Photos by Kathleen Hatt.
Most folks in this part of the country are familiar with the basic process of making syrup: tap some trees, collect the sap, boil it, boil it some more, bottle it, and take it to market. In general, the process for making maple and birch syrups is similar. It's the details that differ. "If you try making birch syrup in the same way you make maple syrup, you'll be disappointed," says David Moore of The Crooked Chimney sugarhouse (http://www.crookedchimneysyrup.com) in Lee, N.H. For starters, you don't boil birch sap. Boiling would scorch it.
Moore began experimenting with birch syrup in 2008, while he was a student at the University of New Hampshire. Since then he's learned a lot about birch trees, birch sap and birch syrup. Unlike maple sap, which contains sucrose, birch sap contains fructose, and the concentration of fructose in the sap of each species of birch tree is different. Moore determined this by collecting sap from white (or paper) birch (Betula papyrifera), sweet (or black) birch (Betula lenta), and yellow birch (Betula alleghaniensis) trees in the same general area and measuring the sugar content of each. He found that at approximately 1 to 1.2 degrees Brix, sugar concentration is highest in paper birch sap. Sweet birch and yellow birch sap have less, both approximately 0.6 degree Brix. All are far below maple sap. "If you were to finish birch syrup at the same Brix as maple [72 to 74 degrees], birch syrup would be much thinner," says Moore.
Each birch tree gets only one tap. Sap must be collected in either plastic or stainless steel containers.
Photos by Kathleen Hatt.
Birch sap starts running when maple sap is nearly done running. However, birch sap only runs one and a half to three weeks before the trees bud. Birch sap flows so rapidly that Moore must collect sap once a day. Because the sap reacts with many metals, it must be collected in stainless steel or nonmetallic buckets. Moore uses covered 5-gallon plastic buckets. In 2013 he collected 910 gallons of sap. It takes over 100 gallons of birch sap to make 1 gallon of syrup. That's more than twice as much as the approximately 40 to 50 gallons of sap needed to make 1 gallon of maple syrup.
Scouting throughout the town of Lee, Moore selected 226 birches suitable for tapping. White birch is an early successional species often found along woodland edges and in overgrown pastures, while sweet and yellow birch are late successional species found in mature forests. White birch is also used in residential and commercial landscaping. Moore taps trees that are 10 inches or more in diameter. Approximately 95 percent of the trees he taps are white birch - the most widely distributed, east to west, of all North American birches. The rest are primarily sweet birch, with one or two yellow birch trees thrown in. Each tree gets only one tap, a 5/16-inch plastic tree-saver type. Although long tubing lines could be used with birch just as they are with maple, it is not feasible for Moore, since he does not own the land.
Birch sap degrades quickly, and unless it is kept cool (40 degrees Fahrenheit or less), it must be simmered within one day of collection. Moore pours sap from collection buckets directly into an organic felted wool filter, preferred because it strains out larger unwanted particles. Following filtering, the sap passes into a stainless steel 3-by-12-foot Leader evaporator. Extra sap is collected in a 125-gallon tank, but because the tank is not cooled, Moore cannot store sap longer than a day or two.
In 2013, 1.5 cords of hardwood kept the evaporator running throughout the three-week-long season. By using only hardwood, Moore is able to avoid scorching by maintaining a consistently low temperature, just below the boiling point of water. In this way, evaporation proceeds at the rate of about 15 gallons an hour. The process continues throughout day and night. As the sap thickens, the boiling point rises. Since the sap does not boil as it does in maple syrup making, no defoamer is needed.
David Moore pulls a tap on April 8, the end of the 2013 birch syrup season.
Options for processing more efficiently exist. For instance, it would be possible to use the same reverse osmosis machine used to process maple syrup, since birch sap flows a bit later than maple. Of course, the machine would have to be thoroughly cleaned in between the processing of maple and birch saps. A reverse osmosis machine would allow birch syrup producers to process sap quickly and avoid scorching. A double boiler is another option for processing birch sap.
A far north tradition comes to New England
Collecting birch sap has long been a rite of spring in the world's circumpolar regions. Indigenous peoples of Alaska, Russia, China and Scandinavia consider birch sap both a spring tonic and a refreshing beverage just as it comes from the tree. For those who evaporate water from the sap to make syrup, it is also a good way to finish off the winter's wood supply. In Alaska, which now produces approximately a quarter of the world's birch syrup (estimated in 2004 to be 1,500 gallons), the first attempts at commercial production were made more than half a century ago, during periods of sugar shortages. Steam boilers left behind from early mining operations were modified for use in the endeavor. The more successful of those early operations used steam at a controlled temperature to boil the sap without scorching, resulting in a light syrup suitable for table use. The high cost of production put a stop to those early efforts.
Birch trees have many food uses. Although other uses may be less profitable than syrup, birch sap can also be used to make beer, wine and vinegar. According to the USDA's Plant Guide, both the sap and inner bark of white birch can be used as emergency food, and the inner bark can be dried and ground into meal to be used as a soup thickener or bread flour extender. Tea can be made from the roots, bark and young leaves. Birch can also be used to make soap, shampoo, canoes, buckets, baskets and medicine.
Carrying a bucket of birch sap, David Moore passes the last of the 1.5 cords of hardwood he cut for the 2013 birch syrup season.
The future of birch syrup
In Moore's experience, birch syrup sells out quickly. "People like novelty, and there are always some who want to taste a new flavor no matter the cost. Chefs are particularly interested in birch syrup's distinctive flavor - sometimes described as somewhat fruity - for use as an ingredient," says Moore. Michelle Moore, David's mother and devoted evaporator tender, has long cooked with birch syrup and describes its flavor as deep, earthy, robust and somewhat sweet.
To acquaint his fellow New Hampshirites with the unique flavor of birch, Moore takes his to farmers' markets throughout the Granite State, where he sells 8-ounces bottles of birch syrup for $25. In his first year of production he selected two markets in each New Hampshire county and took his syrup to each only once.
The feasibility of producing birch syrup in the Northeast and of diversifying maple syrup operations to include birch syrup is the subject of research by the University of Vermont's Proctor Maple Research Center, Cornell University and the University of Maine Cooperative Extension.
In 2013, Moore made 5 gallons of birch syrup. Until and unless supply begins to exceed demand, market prices for birch syrup are likely to remain high. For now, there's room for more birch syrup producers.
Kathleen Hatt is a freelance writer and editor and has been a frequent contributor to Farming since 1998. She lives in Henniker, N.H.