From: hwt@bcarh11a.BNR.CA (Henry Troup)
Newsgroups: rec.food.sourdough,rec.food.historic
Subject: Tapping Maples, making syrup (long)
Date: 6 Nov 92 18:42:59 GMT
Reply-To: Henry.Troup@BNR.CA
Followup-To: rec.food.historic
Distribution: world
Organization: Bell-Northern Research Ltd., Ottawa, Canada


Ok, this I've done (at a Living History site).

First, you need a maple a minimum of 25cm (10 inches) in diameter near
the ground, in good health.  Then, you need the right climate.  To get
maple syrup, you need long cool springs - +5 C in the day and -5 C at
night (40 and 25 F, about). City maples should not be tapped.

You tap the tree by drilling a hole about 1.5 cm (5/8 inch) diameter,
about 5 cm deep (2 inches).  This happens to be the size of a standard
'spile', the hollow plug you put in it.  Commercial spiles have a hook
to hang a bucket on, btw.  The hole only needs to be at a useful height,
waist level or so.  It should be about 15 cm (6 inches) horizontally
away from previous tap scars.

A tree will take one tap if it's 25cm, and one more per 10 cm girth - a
really big old tree can handle 4 taps, but is a rare size!  It's best to
tap on the south side.

The sap is 1-2% sugar.  You can drink it (or make boiled coffee)
straight - lots of vitamins.  Or, make syrup.  

It takes a 40:1 reduction, bringing the sugar content to 66%.  Straight
boiling is all it takes.  Do this outdoors!  A propane barbeque is ok
for home use.  Trees under stress should not be used.

Typically, several stages of boiling are used.  At the farm I volunteer
at, we have a 500 litre primary evaporator to go to about half volume,
then open cauldrons (50 litre), then pots on a stove.  Then filter - our
filter is felt.  A candy thermometer does nicely to know when the syrup
is ready.

Tapping trees does harm them - it kills an area about 8 cm diameter. 
The big trees will tolerate tapping for fifty years or so.  Maple syrup
trees are no good for lumber, btw, only for firewood.  A tree needs to
be at least 20 years old.  A good year will see 250 litres of sap or
about 4.5 litres of syrup from one tree.  The season is rarely as long
as a month.

Sap doesn't keep - it ferments in a day or so.  Drain the buckets daily
and boil daily. Sap will freeze in cold nights - if not solid, throw off
the water ice. You could freeze sap to preserve it.  You'll need to be
tapping several trees to have a worthwhile boil; then you'll have a lot
of syrup.

The taps are removed when the maple buds break or the sap turns milky. 
At that time, it starts to taste bitter. 

The entire world maple syrup production is in eastern North America
(with a little pocket in Manitoba).  Yellow birch is tapped for
feedstock for the production of xylitol sweetener, but that's a chemical
reaction.

Commerical syrup is often concentrated with reverse osmosis, especially
to get light grade syrup.  The energy cost of boiling is the major cost
of maple syrup.

I haven't mentioned pipeline systems, Sunday buckets, or native American
techniques.  If you want to know, ask.

Henry Troup - H.Troup@BNR.CA (Canada) - BNR owns but does not share my opinions
"I disagree with what you say but will defend to the death your right to
say it"