Sycamore syrup tastes quite different than maple and birch syrups. In general, it’s difficult to harvest sycamore sap without using a vacuum pump, but sometimes conditions are right and sycamore trees can generate enough stem pressure to exude sap at atmospheric pressure. Unseasonably warm midwinter days that follow freezing periods coupled with rain events seem to cause large stem pressures to build in sycamores. Using a vacuum pump, it’s possible to harvest sycamore sap during freeze-thaw cycles and at warmer temperatures too. Like birch sap, sycamore sap should only come into contact with plastic, stainless steel, and glass equipment; other types of metals will impart a terrible off-flavor on the sap because of how acidic sycamore sap is. Sycamore sap is also pretty dilute – sap from American sycamore (Platanus occidentalis) is often around 0.7 ° Brix, and the sap-to-syrup ratio is, in our experience, around 130 to 1. We’ve also tapped and successfully made syrup from London planetree (Platanus x acerifolia). Sycamore sap contains very little sucrose and lots of fructose and glucose, so care should be taken not to process sap for too long at temperatures that are too high.