Current situation

A return of cold weather to much of southern Ontario has stopped the chance of early season sap flow for now.  Cold weather is a good thing however, which will help delay the best sap flows until after February when the better sap flows can be expected.   Very early sap flows are often low in sugar concentration and may not be economical to process into syrup anyway.   It is better to wait but be fully ready.  It is better now to focus on getting all maple processing equipment and measurement equipment ready and properly calibrated for the upcoming maple syrup season.

Deciding when to tap

Prior to tapping trees, each maple syrup producer should decide the condition of health of their sugar bush.   Some questions to ask yourself include:  Were maple trees under any stress during the 2008 summer growing season?  Were insect pests such as tent caterpillar or gypsy moth a serious problem?   Are maple trees under stress due to over-tapping from previous years?   Answers to these questions can help maple producers decide the amount of tapping they can use for the 2009 tapping season.

Tapping guidelines

The following is a list of guidelines that are good to know for new maple producers and a good reminder for experienced maple producers. The tapping guidelines are important to help safeguard the longterm health of tapped maple trees and to help producers collect the best possible yields of quality sap.

• If possible, tap maple trees when the trees are not frozen, or at least drill tap holes when temperatures are above -5 ˚C, to prevent splitting damage to bark and sap wood above and below the tap when spouts are tapped into the freshly drilled holes. 
• When drilling, use drill bits that are sharp and of the proper diameter for the spouts, use drill bits that are clean and sanitized several times during the day. 
• Do not tap maple trees that are less than 25 cm (10 inches) in diameter at chest height, or about 4½ feet above the ground.  Deep snow in sugar bushes will place tap holes higher than chest height. 
• For healthy trees, limit the number of taps per tree to a maximum of 3 taps for the largest trees. 
• Maple tree that were stressed during the 2008 growing season by excessive ground water or by insect defoliation are still likely under stress from last year.  Where some tapping in stressed trees is done, only tap large diameter trees with no more than 1 or 2 taps per tree. 
• When drilling taps, drill to a maximum depth of 2 inches into healthy sap wood on a slight upward angle to promote sap flow down the spout. 
• Wood shavings coming off the drill bits should be a healthy whitish cream colour.  Bit shavings that are brown or black indicates you have drilled into decayed or stained wood.  Decaying wood should not receive a spout due to poor sap flow and off flavours in the sap.  Move to a new area on the trunk that looks outwardly healthy and drill a new tap hole showing healthy white sap wood. 
• Tap trees uniformly around the tree at least 4 to 6 inches to either side away from last years tap holes.  Maintaining a good distance between tap holes helps to reduce finding stained wood in the sap wood and helps to keep the sap flowing well inside the trees. 
• Maple producers using tubing systems are encouraged to use the smaller diameter spouts 5/16 or 19/64 inches in diameter that are now available instead of the larger 7/16 inch spouts.  Research has shown that smaller holes for smaller spouts will heal over faster during the spring and summer in one or two seasons, which means maple trees will be that much healthier each year with less damage.

Production reminders

Producers are reminded that the sugar concentration for finished maple syrup must be a minimum of 66%, or 66 ˚Brix, for maple syrup to be legally marketed in Ontario.  Sugar concentrations of 66.5 to 67.5% in syrup will give best maple flavour and viscosity for maple syrup.    

Boiling point temperature elevation is often used to determine when ideal sugar density is reached.  Maple syrup reaches an optimum sugar density at boiling point temperatures between 4.0 ˚C to 4.3 ˚C (7.3 ˚F – 7.7 ˚F) above the boiling point of water.  

When measuring boiling point temperatures of syrup, in reference to the boiling point of water, it is very important to understand that the boiling point of water varies with changes in barometric pressure.  It is essential to determine the actual boiling point of water every time a new batch of sap is boiled and finished syrup is measured.  Even one temperature degree of error can make the final measurements of sugar density either higher or lower than what the producer thinks.  Syrup having a density much higher than 67.5 ˚Brix can be too thick and may have problems with crystallization of solid sugars in the finished product.    

Cleanliness is important for maple syrup production.  Excessive micro-organism buildup in sap can reduce syrup quality by affecting the flavour.  Bacteria in sap break up the main sugar, sucrose, reducing it quickly to the other sugars, glucose and fructose, which react to heating differently than sucrose and impart different flavours in finished syrup.  Sap filtration equipment can help reduce microorganisms ahead of short term sap storage tanks and evaporators.  Various sap filtration units, or UV light treatments, are available that are effective at removing or killing much of the microbial buildup.

This report has been prepared by Todd Leuty, Agroforestry Specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs.