How much black walnut sap makes a gallon of syrup?

About 25 to 43 gallons of sap make one gallon of syrup at its usual 2–3.5% sap sugar, by the updated Rule of 86. Tastes surprisingly like maple, with a nuttier edge. Expect only about 6–11 oz of syrup per tap (maples typically give 32–64 oz), and plenty of pectin that clogs filters much faster than maple's sugar sand.

When do you tap a black walnut?

Tap in late winter, like maple — Cornell's trials tapped most trees in mid-February. Walnuts can flow in fall too, but that sap is barely sweet.

Juglans nigra

Can you tap a black walnut?

Short answer

Fair, lower yield

Yes, with caveats. Sweet sap and nutty, maple-like syrup — but only a trickle compared with a maple, so treat it as a fun side project.

Sap sugar: 2–3.5%
Sap : syrup: 25–43 : 1

Black walnut trunk with dark gray-brown bark in rounded, interlacing ridges forming a rough diamond pattern — Photo: Ryan Hodnett, CC BY-SA 4.0

Black walnut winter twig close-up: a large three-lobed “monkey face” leaf scar beneath fuzzy gray-tan buds — Photo: DouglasGoldman, CC BY-SA 4.0

Black walnut branch with long compound leaves of many lance-shaped leaflets and two round green walnuts — Photo: Famartin, CC BY-SA 4.0

Black walnut in a city park with a thick, dark furrowed trunk, spreading limbs and feathery compound foliage — Photo: Rhododendrites, CC BY-SA 4.0

Leaf-off ID

Identify it in winter

01Alternate branching on thick, stout twigs.
02Big three-lobed leaf scars — the classic “monkey face” — sit just below fuzzy tan buds.
03Slice a twig lengthwise: the pith is chambered into little compartments and buff-colored.
04Bark is dark brown, ridged and furrowed in a rough diamond pattern.
05Look underneath: round walnuts 2–2½ inches across in thick husks.

In summer

Big compound leaves 12–24 inches long with 10–24 finely toothed leaflets; the end leaflet is often missing or runty.
Round green walnuts, 2–2½ inches across, ripen from late summer into fall.

Easily confused with

Butternut

Lighter, ashy-gray bark with flat, shiny-topped ridges; dark-brown chambered pith; a fuzzy “eyebrow” above each leaf scar; and lemon-shaped nuts.

Maples

Walnut is alternate-branched with huge leaf scars; every maple is opposite.

Sap sugar: About the same as maple — roughly 2–3.5% in spring (under 1% in fall)
Season: Tap in late winter, like maple — Cornell's trials tapped most trees in mid-February. Walnuts can flow in fall too, but that sap is barely sweet.
Syrup: Tastes surprisingly like maple, with a nuttier edge. Expect only about 6–11 oz of syrup per tap (maples typically give 32–64 oz), and plenty of pectin that clogs filters much faster than maple's sugar sand.
Range: Eastern U.S. from Vermont and southern Ontario west to Minnesota and South Dakota, south to Texas and northwest Florida (skipping the lower Mississippi Valley).

Tapping it?

Sources · 4

1.Tapping Walnut Trees for a Novel and Delicious Syrup (M. Farrell) · Cornell Small Farms Program
2.Black Walnut (Juglans nigra) — Williams · USDA Forest Service — Silvics of North America (Agriculture Handbook 654, 1990)
3.Black walnut (Juglans nigra) — Virginia Tech Dendrology Fact Sheet · Virginia Tech Dendrology (Dept. of Forest Resources & Environmental Conservation)
4.Butternut (Juglans cinerea) — Virginia Tech Dendrology Fact Sheet · Virginia Tech Dendrology (Dept. of Forest Resources & Environmental Conservation)

FAQ

Black walnut questions

Can you tap a black walnut for syrup?: Yes, with caveats. Sweet sap and nutty, maple-like syrup — but only a trickle compared with a maple, so treat it as a fun side project. Its sap sugar is about the same as maple — roughly 2–3.5% in spring (under 1% in fall).
How much black walnut sap makes a gallon of syrup?: About 25 to 43 gallons of sap make one gallon of syrup at its usual 2–3.5% sap sugar, by the updated Rule of 86. Tastes surprisingly like maple, with a nuttier edge. Expect only about 6–11 oz of syrup per tap (maples typically give 32–64 oz), and plenty of pectin that clogs filters much faster than maple's sugar sand.
When do you tap a black walnut?: Tap in late winter, like maple — Cornell's trials tapped most trees in mid-February. Walnuts can flow in fall too, but that sap is barely sweet.

Tree ID