How Does a Maple Syrup Evaporator Work

Evaporators are generally housed in a sugar shack like this one.

If you're wondering, "How does a maple syrup evaporator work?", you may be surprised to find that the process is lengthy but rather simple.

How Does a Maple Syrup Evaporator Work

The process to obtain even an ounce of maple syrup is quite lengthy. It takes between 30 to as much as 50 gallons of sap to produce one gallon of maple syrup. The exact amount of sap required varies based on how sugary the sap is. One tree can yield around ten gallons of sap. . .so to get one gallon of maple syrup, about five to seven trees have to be tapped.

While most people who live around places where maple sugaring is plentiful have seen sap collecting buckets on trees in mid-winter, what happens afterwards may not be quite as obvious. Since sap contains a substantial amount of water, the water of collected sap has to be boiled off and to do this, major maple sugaring farms use a commercial evaporator.

How Commercial Evaporators Work

A typical maple syrup evaporator consists of at least one, but generally two metal pans that are placed over a fire box. The fire box is usually referred to as an arch. The pans have "walls" that are not closed, dividing the pan into open sections. Syrup can move freely throughout the pan, but the division walls have the effect of helping separate the more concentrated syrup from that which is more dilute. The water can evaporate more easily this way than if the pan were just one whole.

Because the sap must reach such a high temperature in order to boil off all the water, the sap pan has what are called flues on the bottom. Essentially, the flues service to increase the surface area for heating. The idea is that the more heated surface you have, the more quickly the syrup will reach a state where the water is evaporating off.

All of these pans fit together over a "stove" of sorts that essentially is kept extremely hot to help speed the evaporation process. It takes at least a full day to yield a gallon of syrup - and all the while, people have to be watching to make sure that the process is running smoothly.


Although answering the question, "how does a maple syrup evaporator work", isn't complicated, it is a lengthy process which explains why pure maple syrup is so expensive.

How Does a Maple Syrup Evaporator Work