spile

Spile, plural spiles, is a small hollow tube or spout used to extract sap from trees during sap collection, most commonly in maple sugaring. A spile is inserted into a drilled or bark incision in the tree to create a conduit from the tree’s vascular tissue to a collection vessel such as a bucket or a tubing line. Sap flows through the spile as temperatures fluctuate around freezing, typically in late winter to early spring in temperate regions.

Spiles are made of metal, wood, or plastic. Wooden spiles are often hollow dowels with a slit or bore that directs sap outward; metal spiles may be cone-shaped or barbed to stay in place and may have an angled outlet; plastic spiles are common in modern systems and are frequently connected to tubing. The choice of material influences durability, ease of use, and sanitation.

Tapping guidelines emphasize selecting a tree of sufficient size, drilling a hole about 1 to 1.5 inches deep, at a slight downward angle, and inserting the spile so sap can flow freely. After sap collection, spiles are typically left in place for the season or removed with care to minimize damage, and the entry hole is cleaned or sealed to prevent disease.

In North America, sap collection with spiles is central to producing maple syrup, with sugar content in sap usually around 2 to 3 percent, requiring boiling to concentrate the sugars into syrup. Spiles are also used for educational demonstrations and in some traditional or artisanal tapping practices.