Steps 1-3 below describe the method for tapping trees. Steps four and five describe the method for making syrup.
 You'll know that "sap's up" when freezing nights are followed by warm—and usually sunny—days. Choose trees that are at least 10" in diameter (except in the case of the canyon maple, which should be a full 8") for single taps, 16" for two taps, and 22" or more for three taps. The spouts (also called spiles) can be made from sections of elderberry, sumac, bamboo, willow, or mullein stem with the pith removed ... or you can use crimped pieces of curtain rod or lengths of plastic tubing.
 Drill a 3/4 "-diameter hole-from 2 " to 3 " deep-on the south side of each tree. Be sure the bore takes a slightly uphill angle, and is at a convenient height. (Sap flow is usually heaviest below a large limb or above a big root.) Tap the spile in gently to avoid splitting the wood.
 Hang a clean and rust-free bucket, a plastic milk jug, or some other one- to five-gallon container securely under your spout, making sure it's adequately covered to keep out snow, rain, dirt, etc. Roughly speaking, you can expect 20 gallons of sap from each tap. You'll need about 40 gallons to make 1 gallon of syrup. (Sap sours easily in warm weather, which means you must gather it frequently, keep it cool while it's being stored, and boil it up as soon as possible. Clean plastic trash cans—set in the chilly outdoors—make good holding tanks.)
 The steam produced when boiling down any significant quantity of sap would coat your kitchen's walls with moisture, so plan to cook the syrup outside, on a fireplace made of concrete blocks, or a metal drum. Construct the "stove" so that the flames lick the bottom of your cooking container, but don't let smoke come in contact with the brew, as it will affect the syrup's taste and color.
Use a large, flat pan as your boiler. Keep the contents about two inches deep, slowly adding fresh sap as needed. (This can be done almost automatically by punching a small hole—the size will be determined by the rate of dehydration in your pan—in the bottom of a large can situated above the cooking pot, and then ladling sap into this "preheater".) From time to time, skim off the foam that forms on top of the syrup, using a kitchen strainer or a skimmer made from a 3" X 4" piece of wire screen in a metal frame with a wooden handle.
 After hours of cooking with no apparent change, the syrup will suddenly thicken very quickly. It must be stirred and watched carefully during this critical stage. When the temperature reaches 7° above boiling (be sure to compensate for your altitude when figuring the boiling point) or when the liquid runs off a ladle in thin sheets, the syrup is done. Strain your natural sweetener through a heavy felt strainer bag while it's still warm, then reheat the treat to 160 °F. Pack it in sterilized containers with airtight seals, where it will keep indefinitely!