Water from Sap:
Increasing Energy Efficiency with
flowing out of the maple tree contains anywhere from 1 6% sugar.
Finished maple syrup is 66-67% sugar. To increase the sugar
concentration of sap, many gallons of water need to be removed.
For example, to produce one gallon of syrup, 43 gallons of sap
with 2% sugar content are needed. This means that 42 gallons
of water must be removed from the initial 43 gallons of sap.
maple operations, the water is removed by boiling the sap. The
cost of fuel needed for boiling is a large part of the total
cost of producing maple syrup. Therefore, any increase in fuel
efficiency during this process will benefit the maple producer.
think of any ways to increase the efficiency of removing all
that water from sap to produce syrup?
Table 1 we have included eight different means of processing sap to
syrup. The wood-fired and oil-fired evaporators are basic means of boiling
sap. The sap pre-heater increases the efficiency of boiling sap, by
recycling steam from the evaporator to warm the fresh sap. The piggyback
(steam-enhanced) unit uses both recycled steam and forced air to warm
and concentrate the sap before it enters the evaporator. The reverse
osmosis, freeze concentration, vacuum evaporator, and vapor compression
evaporator use different means to concentrate the sap before it enters
All of these systems
have been created by maple producers who enjoyed designing and experimenting
with new ways of processing sap. Even today, some of these systems,
such as freeze concentration, are still experimental and not commercially
available. If you get an opportunity to visit maple producers, you
may find some who have designed other systems to recycle steam and
increase efficiency. And you may be able to come up with new ways
of increasing the efficiency of producing syrup from sap.
We have included
"functional" designs of the different systems to help you
understand the overall process of syrup production. We also hope these
designs will get you thinking about other energy-efficient systems
to produce syrup from sap.