About Birch Syrup
According to The Birch Syrup Production Manual by Heliose Dixon-Warren, people have known about the health benefits of birch sap for ages. In the early 1900s, Alaskans, driven by a post-World War I sugar shortage, processed birch sap on modified steam boilers left over from mining operations. Today, birch syrup production is an important commercial industry throughout Alaska and Canada, though there are still relatively few producers.
Making birch syrup is very similar to making maple syrup. We tap our trees in the springtime before they bud out, boil the sap down into syrup on a wood-fired evaporator, and bottle our hot syrup before sending it off to market.
There are, however, a few key differences. Birch sap is more acidic than maple sap and when birch sap comes into contact with many metals (such as aluminum, copper, and galvanized steel), the metal will partially dissolve in the sap; some of these metals can impart a metallic flavor on the finished syrup. Therefore, all of our processing equipment is plastic or stainless steel.
Birch sap must be processed below its boiling point. Maple syrup’s primary sugar is sucrose, whereas birch sap contains primarily fructose and glucose. Due to its high fructose content, birch syrup will scorch at a lower temperature than maple syrup. A good rule of thumb is to prevent any boiling from taking place in the evaporator once the sap begins to turn amber in color. We accomplish this by using only hardwood in our evaporator; other producers use propane as their heat source. Reverse osmosis systems are of great benefit to birch syrup producers because they allow the sap to concentrate without the use of heat.
Sap runs in birch trees later in the spring. When daytime temperatures are in the 50s (Fahrenheit) and nights are in the 30s, birch sap flows best. This typically occurs immediately following maple sugaring season. Birch sugaring season is shorter as well – it usually only lasts for 2 or 3 weeks.
To reach the same viscosity as maple syrup, birch syrup must be finished at a slightly higher concentration. Our syrup is finished around 72 degrees Brix.
Paper birches are the best trees from which to make syrup. The sap from paper birch trees is more concentrated than the sap from other species of birch trees (such as yellow birch and black birch). Any tree in the genus Betula can be used, provided that it is large and healthy.
It takes well over 100 gallons of birch sap to make 1 gallon of syrup! Sap coming out of birch trees is usually between 0.5 and 1.5 degrees Brix.
Uses for Birch Syrup
Our favorite uses for birch syrup include:
A sweetener for coffee
An addition to baked goods (especially cookies and blondies)
A glaze for steak, salmon, and root vegetable dishes
An addition to yogurt or granola
A glaze for muffins and pastries
A topping for ice cream
A salad dressing (mix it with balsamic vinegar and olive oil)
Birch Syrup Research
In 2009 and 2010, we measured the sugar content of the sap from three different species of birch trees: paper, or white, birch (Betula papyrifera); black, or sweet, birch (Betula lenta); and yellow birch (Betula alleghaniensis). This study took place in Lee, NH, and Durham, NH. We used a sap refractometer to measure the concentration of dissolved solids in the raw sap every three days throughout the syruping season. Here are the results. We’re happy to answer any questions about this research.