Hocus Pocus Reverse Osmosis
Maple syrup is nature’s magic. Magic implies illusion. Prepare yourself to learn scientific explanations for three illusions regarding maple syrup. Maple syrup is much more than a calorie-rich, fattening sugar solution. Maple syrup is a product from maple tree sap that flows in more ways than up from the roots. Maple tree sap is only 2 percent sugar, but can be concentrated 10 times by syrup producers defying usual physical laws.
Maple syrup production involves time consuming processes. Sugar maple tree sap is collected in the spring from a drill hole in the tree trunk. Sap is boiled in a metal pan over a wood or gas fire to evaporate water. When properly thickened or concentrated, the newly created syrup is filtered, and then poured into sterile containers for consumption and storage. Typically, maple syrup producers collect 10 gallons of sap from one mature healthy sugar maple tree which is boiled for six hours to produce one-quarter gallon of syrup with sugar concentration of 66.5 percent.
Now, for the magic, maple syrup appears to be just sugar, but is a health food in disguise. Yes, the sugar is sucrose identical to table sugar, but the heating process alters some sugar to create the appealing maple flavor. Maple syrup contains significant quantities of iron, calcium, vitamins, amino acids and phenols, recently found to be helpful treating and preventing chronic human diseases. Researchers in Quebec, Canada, have isolated many beneficial compounds in maple syrup which play a key role in human health.
Common sense suggests maple tree sap flows up from the roots when the weather warms above freezing in the spring. Plant physiologists, after injecting red dye above and below a tap as well as on the opposite side of the tree on separate days collected red dye from the tap, thus concluding that sap runs up, down, left and right in the maple tree. Sugar maple branches and twigs perform as if they were microscopic straws through which water flows to and from the roots in channels, called xylem, gathering sugar, amino acids and nutrients. Unique to maple trees, carbon dioxide gas exists in the channels. As the branches are warmed to near 40 degrees Fahrenheit during the day, the gas expands, creating pressure to push sap up, down and around the branches.
Sap, forming frost in the channels during freezing nights pushes sap up and down channels similar to the frost heaving pavement on city streets which leaves pot holes. After a freezing night, sap may ooze at 20 psi (automobile tire pressure is 35 psi).
The third illusion to be explained is how maple syrup producers increase the sugar concentration in sap from 2 percent to 14 percent or higher in the blink of an eye. This is done with a reverse osmosis apparatus.
A practical example of regular osmosis occurs in the human intestines. Swallowed water passes through the semi-permeable membrane of the intestinal wall into the blood stream in an attempt to equalize or dilute the concentration of chemicals in the blood.
With an expensive reverse osmosis apparatus demonstrated to me by Lloyd and David Munsee, owners of Big Tree Maple in Lakewood, last week, large quantities of water can be removed from sap. This is accomplished by directing sap under high pressure through semi-permeable membranes, forcing water out of the sap but leaving the sugar therefore reversing normal osmosis. The “rule of 86” states that the number of gallons of sap required to produce one gallon of syrup is determined by dividing the sugar concentration into 86. Sap at 2 percent concentration therefore requires 43 gallons of sap. If sugar concentration is 14 percent after reverse osmosis, only 6.1 gallons of sap is required to make one gallon of syrup. Now with advanced technology, less fuel is required to produce one gallon of syrup.
Maple syrup production is a labor of love, but a miracle in a bottle for the consumer. Where can we find a better tasting health food that in my opinion is on a par with beer, wine and milk when all are consumed in responsible amounts?