Monday
March 6, 2006
news@michigandaily.com

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SCIENCE

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Th swe melo

Maple sugar
production in
Michigan has
a long tradition
By A. J. Hogg
Daily Science Writer
Michigan's oldest sweetener comes
not from a cane, but from a tree.
In winter a small hole is drilled in a
sugar maple tree or one of its relatives
- a silver, black, or red maple - and as
the frigid days warm up, sap flows out.
From this raw material, producers are
able to make maple syrup and sugar.
"It's definitely a spring signifier,"
said Michelle Arquette-Palermo, pro-.
gram coordinator in the education
department of the Cranbrook Institute
of Science.
Cranbrook is teaming up with
Whisper in the Woods, a nature jour-
nal based in Traverse City, for the
Maple Sugar Festival. The festival
will be held March 11 and 12 at Cran-
brook's 200-acre Bloomfield Hills
campus. Trees have been tapped for
the festival since February, and their
sugar hut will be fired-up and mak-
ing maple syrup on site. There will
also be activities pertaining. to the
outdoors - including bird watching,
winter survival skills and geocaching,
a hide-and-seek game that uses Global
Positioning System technology. Cran-
brook has hosted the maple sugar fes-
tival for the past 32 years.
"It's a nice, natural fit for our sur-
roundings," Arquette-Palermo said.
The University will also hold an
event for families Saturday, March
11, at the Dearborn campus's natural
areas.
"It ties in with the forest, with the
change of seasons, with history, with
social studies," said Rick Simek, pro-
gram supervisor for the Environmen-
tal Interpretive Center of the Natural
Areas at the Dearborn campus. "It's
also about living in Michigan."
Simek coordinates sap collection
and syrup making, which continues
until March 16.
"We're not set up for commercial
production," Simek said, "But we find
ways to enjoy it."
Volunteers can attend an end-of-
season breakfast which inludes syrup
they helped produce. Simek hosted
a public tree-tapping Feb. 11, when
they put in between 55 and 60 taps.
Cranbrook tapped a similar number
of trees.
Collecting sap
Maple trees are unusual in two ways
that allow them to produce syrup. The
first is that their sap contains signifi-
cant amounts of sugar, mostly sucrose.
Second, the freezing and thawing of
the tree in the early spring causes sap
to flow out of drilled holes or wounds
in the bark.
Sugar (or hard) maple is the best,
with up to 3 percent sugar in the sap.
Black, red, silver maples and even
birch also have sweet sap, though in
lower concentrations.
Sap is made mostly of water,
but also contains sugars and trace
amounts of amino acids and minerals,
which, when concentrated, are what
give maple syrup its distinct taste.
Trees circulate their internal liq-
uids through two structures - verti-
cal tubes called xylem and phloem.
Xylem make up the trees rings that
can be used to tell how old the tree is.
They carry water up the trunk, and
also help to physically support the

tree.
Phloem, which are near the bark
surface, carry nutriefts and sugars
around the plant and are tapped for
maple sap.
Trees produce their own food from
carbon dioxide and water via photo-
synthesis in the leaves.
It's not entirely understood why
maples produce a sap flow out of the
tree, but when the maple tree thaws,
positive pressure is produced, and if
the tree is punctured or a branch is
broken, the sap is forced out.
This pressure is likely due to cel-

PHOTOS BY A.J. HOGG/ For the Daily

A sugar hut on the grounds of the Cranbrook Institute of Science.

Austin Arquette, a Cranbrook visitor, drives a spile into a tree.

Plants store starches in their roots
to bank energy for spring. This is why
carrots (a root vegetable) are so sweet.
When water is taken up by roots, these
starches convert to sugars and dissolve
in the sap.
To maximize sap flow, freezing
nights followed by above-freezing
days are needed. Ideal conditions, a
sunny day above 40 degrees Fahren-
heit after a very cold night, can pro-
duce a "gusher" - a tap that produces
one drip per second. At this rate, the
sap buckets will fill in two hours.
"Those 40-degree days and 20-
degree nights don't just happen any-
where," Arquette-Palermo said.
This is why maple syrup production
is limited to the northeast (Vermont is a
major producer) upper Midwest and the
Canadian provinces of Ontario and Que-
bec. Few other regions have the neces-
sary climate.
Michigan is currently the sixth larg-
est U.S. producer of maple syrup, but
only takes advantage of 1 percent of
its capacity.
Tapping the tree. by hand can be a
difficult process.
"My arm's getting really sore"
Arquette-Palermo's son Austin said while
tapping a tree by hand. Most syrup pro-
ducers no longer use hand drills.
Once the hole is drilled a few inches
into the tree, either by hand or power
tool, a small metal spout - called a
spile - is hammered into the tree. A
bucket collects the sap as it drips out,
and is covered to keep rain, bugs and
other material from getting into the
bucket. The bucket is collected daily,
when the sap is flowing.'
The sap, at 3 percent sugar, is just
barely sweet. Some people claim
that they can taste the distinct maple
flavor, but others think it tastes like
water. However, once the sap dries
on a finger, it leaves a thin but sticky
sugar residue.
Maple syrup production is sustain-
able, because tapping only uses 10
percent of the tree's sap, an amount
that studies show a healthy tree can
easily spare.
The length of the syrup season in
southeast Michigan can be as long as
six to eight weeks, or can last only one
week.
"It's very weather dependent,"
Arquette-Palermo said.
If temperatures warm up quickly
enough, the tree buds and sugaring
season ends. When buds are present,
the sap becomes bitter and is unsuit-
able for syrup.
Maple trees have been tapped for
their sweet sap for centuries, and are
mentioned in the earliest journals of
Europeans arriving in North Ameri-
ca. While Native Americans may not
have had the iron kettles Europeans
used to boil down syrup, they almost
certainly collected the sap in wooden
troughs, and boiled it by adding heat-
ed rocks and removing larger chunks
of ice by hand. Removing the ice also
concentrates the sap, since the ice
contains only water, not sugar, mak-
ing it sweeter.
Maple syrup and sugar production
peaked in the United States in 1860.
After that, cheaper cane sugar from
the South and Caribbean, as well as
an increase in the cultivation of sugar
beets, changed the nation's sweeteners
of choice.
Making syrup
Because sap only keeps for a few

sweet, and requires 100 gallons of sap
per gallon of syrup.
You can concentrate, the syrup fur-
ther, and put it into molds to crystallize
it into maple sugar, but most production
today focuses on making syrup.
Early European settlers in North
America used an iron kettle to boil down
syrup. Arquette-Palermo explained the
disadvantages of the procedure: "Talk.
About. A really. Long. Time."
The depth of the kettle reduced
the surface area of the sap, so boil-
ing took longer.
In the 19th Century, sheet metal
evaporators were developed that
increased the surface area of the boil-
ing sap. Shallower pans sped evapo-
ration. Further advances included
preheating the sap, creating an evap-
orator pan where the sap can con-
tinuously convert into syrup, vacuum
pumps to assist pulling sap from the
trees, tubing systems to eliminate the
need for buckets, transporting the sap
from many trees to a storage tank,
and even reverse osmosis machinery
to pre-concentrate the sap.
Cranbrook uses the smallest com-
mercial evaporator available.
"To get syrup, it could be two
to three hours, it could take 12,"
A rquette-Palermo said.

This depends on the starting con-
centration of sugar and the tempera-
ture of the fire. On a good day, they
can produce two batches of syrup.
Syrup, just water with 66-percent
sugar in it, boils at 219 degrees Fahr-
enheit, or 7 degrees above the boiling
point of water.
Finishing the syrup is a delicate
and fast-moving process.
"You sit for hours and hours and
then ... " she mimed frenetic activ-
ity. By law, syrup needs to be, at
minimum, 66-percent sugar.
However, carelessness can burn the
reduced sap, or worse, push it over
the limit so that the sugar precipitates
out of the solution, forming a rock
candy that coats the evaporator and is
astoundingly difficult to clean off.
But when done correctly, the syrup
is filtered and packaged in sterile bot-
tles or cans - ready to be added to
waffles or pancakes.
Until March 16, the University's
Dearborn campus takes volunteer to
collect the sap every day at 4 p.m.,
if the weather cooperates. The night
before needs to have been below
freezing, and the afternoon must top
40 degrees. Keep this in mind March
14, the night the full moon is called
the Sap Moon.

The evaporator in a sugar hut at Cranbrook, which turns maple sap into
maple syrup.

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Participants must be 18 to 65 years old and suffer 2 to
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y are required. Visit 2 is a four- to five-hour treatment
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You may be compensated up to $350 for your time and travel. For more information,
please call a study coordinator.
Michigan Mead*Pain & Neurological Institute
Joel R. Saper, M.D., EA.C.P, Director
3120 Professional Drive, Ann Arbor, Ml " (734) 677-6000, ext. 4