How to Tap Trees: Birch, Walnut, and Sycamore

Want to branch out from maple? Use this guide to decide which trees to tap and learn about making birch syrup, making walnut syrup, and making sycamore syrup.

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Perhaps the greatest disappointment when first exploring my woodlot was the realization that not a single sugar maple tree exists on the entire property. While I’m fortunate enough to have a neighbor who allows me to tap his sugar maple trees, I found myself looking for other opportunities to produce more food from the forest. I began to explore making birch syrup, which I first encountered when I lived in Southeast Alaska. After birch syrup, I quickly discovered an entire world of saps and syrups derived from more than 50 tree species around the world.

Sweet or Savory?

As you explore syrups, you’ll see that they’re subject to just as much enthusiasm as craft beer, with styles varying by region and maker. You’ll also find that while we use the term “syrup” to describe any tree sap that’s condensed, not all syrups are sweet. Birch syrup, for example, has a savory and almost spicy flavor, well-suited for use as a demi-glace over wild game or for a salad dressing. Walnut, however, has a sweet, nutty taste, and the flavor becomes stronger later in the tapping season. The first run of sycamore syrup is usually very light, resembling honey in both appearance and taste. Late-season sycamore syrup has a distinct butterscotch flavor.

How to Tap Trees: Choosing What to Tap

A walk through your backyard or woodlot will give you a good idea of your sugaring possibilities and limitations. While paper birch (Betula papyrifera) is the most commonly tapped birch, all birches in the Betula genus will work. On my property, I happen to have mostly gray birch (Betula populifolia), which is small and short-lived but makes wonderful syrup.

If you’re in the Midwest, Northeast, or Southeast, chances are good that you have walnut (Juglans spp.) or sycamore (Platanus occidentalis) trees nearby. Regardless of the species you choose, realize that making syrup requires a significant time investment. To get just one gallon of syrup, you’ll have to process about 40 gallons of sugar maple or walnut sap, or as many as 100 gallons of birch or sycamore sap!

Also, be mindful that tapping creates a wound that may harm the tree and render it less valuable for other purposes, such as lumber production. This is particularly true for walnut because it’s a high-value wood. You could tap only those trees that have poor form and aren’t likely to be used for lumber. Another approach is to tap a few dedicated sap trees, knowing they won’t yield commercial lumber but will make great syrup.

How many taps can you put into a tree without hurting it? Relatively little research has addressed this question for non-maple species, but commercial producers have erred on the side of caution. Most recommend a minimum 8-inch diameter tap at 41⁄2 feet above the ground and just a single tap for all but the largest trees. An exception would be birch trees, such as gray birch, which are naturally small and short-lived. My tap for these trees may be as small as 5 inches in diameter, and then I’ll cut the stem under a coppice regeneration system

How to Tap Trees: When to Tap

Birch. Tapping birch is popular partly because tapping season immediately follows maple sugaring season. In maples, freeze-thaw cycles produce stem pressure, causing sap to flow, but birches pump sap based on root pressure after most of the snow has melted and the soil has adequately warmed. This allows commercial producers to extend the season by up to six weeks. In most parts of the country, this means birch sugaring season extends from mid-March to the end of April.

Walnut and sycamore. Like sugar maples, both walnut and sycamore trees rely on nighttime temperatures below freezing and daytime temperatures above freezing for sap to flow. These temperature swings create pressure in the trunk of the tree, thereby causing the sap to “run.” In most parts of the Mid-Atlantic and Midwest, this process begins in early to mid-February.

How to Tap Trees: The Process

Tapping. The basic process for tapping birch, walnut, and sycamore trees is the same as it is for maple trees. Select a healthy tree with a large crown. Avoid old wounds and signs of decay, such as mushrooms or conks growing on the tree. Because tapping the tree will create a new wound, make sure your drill bit and taps are clean to avoid introducing bacteria or fungi, which could compromise both the quality of the sap and the health of the tree. The standard tap requires a 7⁄16-inch drill bit. In recent years, smaller taps have been developed (5⁄16-inch and 19⁄64-inch) that allow the tree to heal faster. Regardless of the tap you choose, make sure you use a sharp bit and have a spare battery for your cordless drill. On a mature walnut tree, you’ll want to drill approximately 2 inches into the tree. Because birch and sycamore trees have thinner bark, 1.5 inches will offer sufficient depth for sap flow. Bore your holes so that they slant slightly upward into the tree (to facilitate sap flow) and insert your spiles. You can collect in buckets hung from hooks on the spiles, although some folks use flexible tubing fed into a container on the ground or a wagon.

Harvesting. While birch sap typically offers an unimpressively low sugar content of 1 percent or less, it produces impressive amounts of sap, oftentimes double that of similarly sized maple trees. Given that a single birch tap may produce more than a gallon of sap in a day, you’ll need to develop an efficient system for collecting and boiling the sap. Because the birch sap run is later in spring, when temperatures are warmer, processing the sap before it spoils is imperative. In some cases, it will take just a couple of days to process the entire harvest. For this reason, I recommend starting off with just a few trees.

While the sugar content of walnut is similar to that of sugar maple, the sap yield per tap is usually only about two-thirds of sugar maple trees. Sycamore has sap yield on par with walnut but has significantly less sugar content.

How to Make Syrup: Boiling, Canning, and Enjoying

You can use a maple-syrup-style evaporator for making birch syrup, making walnut syrup, or making sycamore syrup, but I recommend that you boil the syrup on a stovetop because it’s easier to prevent scorching. Boil the sap until it reduces sufficiently. Whether you’re using birch, walnut, or sycamore, your final syrup should be 66 to 67 Brix, as measured with a hydrometer (which measures the relative density of liquids).

You’ll need to filter the syrup while it’s hot to remove minerals and impurities. Use an unbleached coffee filter for small amounts, or try a cone-style felt filter for larger batches of syrup. A filter press is the most effective means of removing impurities, but it’s cost-prohibitive for most home-scale producers

After filtering, the syrup may need to be reheated to attain the proper canning temperature of 180 to 190 degrees Fahrenheit. Fill sterilized mason jars, leaving 1/4-inch headspace, seal with a sterilized lid and band, and store in a cool place or a refrigerator. For long-term storage, keep your syrup in a sealed container in the freezer. Any of these syrups will keep for two years after packaging, assuming you don’t eat them before then!