Maple syrup is made by drilling a spile into the trunk of a maple tree in order to collect its sap, and then boil the sap down into syrup. The process typically takes place in late winter or early spring.
There are four varieties of maple tree that produce sap for making syrup, including sugar, red, black and silver maple trees. Sugar maple trees provide the highest sugar content. The tree produces the sap when temperatures reach above freezing during the day and fall below freezing at night. The fluctuations in pressure allow the sap to flow throughout the tree. For this reason, it is usually possible to collect maple sap during February or March.
To begin, tap the tree by drilling a small hole into the trunk. Using a hammer, insert a spile into the hole. The spile allows sap to flow out of the tree and into a collection bucket placed under it. After collecting enough sap for a batch, put it on the stove to boil. Because sap only has a 2 percent sugar content, most of the water needs to boild away to turn it into syrup.
Once the sap turns a golden color and reduces to approximately half of its original volume, transfer the product into a smaller pot to continue cooking. Using a candy thermometer, remove the syrup when it reaches 219 degrees Fahrenheit. After cooling, store maple syrup in an airtight container, and refrigerate it until use.