Tapping and sap flow summary
In Ontario, the first runs of sap and the start of maple syrup production can vary by two or three weeks across the province. Syrup producers in early areas of southwestern Ontario have been boiling for two weeks, central mid-season areas have boiled one to three times over the past week. The latest areas of eastern and northern regions have remained cold and syrup producers are drilling tap holes when thawing temperatures permit it, and installing spouts in anticipation of the first significant sap flow.
Several areas have reported the first sap was off-colour and flavour. Producers often discard the first sap run due to a ‘metabolism’ off-flavour, which usually clears in subsequent sap runs.
Photo 1 & 2. A modern maple sap extractor is a precision device that separates fresh sap from the vacuum tubing network into bulk collection tanks, with little to no disruption to the vacuum pressure. Extractors can be powered by electricity or by the vacuum itself with mechanical valves. Right photo – simpler times are still celebrated and re-enacted when fresh sap was once boiled down to form blocks of dry maple sugar (Jack Smythe Field Education Centre, Peel Region).
The timing of the season does not predetermine the total volume or quality of syrup produced by each region. We will know the syrup crop results when the season is finished.
Sugar maples thaw to the ground
With increasing day length and mild sunny weather occurring more frequently, snow is melting away from sugar maple trunks exposing the leaf litter and soil. Once exposed and the trunk-root interface has thawed, sap will begin to flow more readily with each sap flow event. While shallow roots located further from the tree may still be frozen under the snow, deeper roots that are unfrozen below the frost line can begin recharging water from the soil into the tree.
Photo 3 & 4. Like a bowl at the base of each tree, snow has begun to melt back this past week as the sun warms the bark. Early areas may have little snow remaining. More than 80% of commercial syrup producers have adopted efficient vacuum collection tubing, yet traditional sap buckets are still frequently hung on sugar maples near the sugar house. Ask for locally produced pure maple syrup in stores, or go to a nearby maple syrup operation and meet the producer.
The concentration of sugar in sap generally increases as late winter gives way to spring. It is a good idea to measure and record sap sugar concentrations during each sap run throughout the processing season. The sugary sap is forced up the tree to rehydrate fibres and cells in the trunk and canopy branches, to provide energy to each dormant bud.
Researchers have measured that syrup production removes approximately 10% of the sugar from a healthy mature maple tree, and they report this is not enough to cause stress to trees.
Hydrotherms and hydrometers
Never consider your density measurement equipment to be your trusted old friend. It is better to eye density instruments with some suspicion. Confidence in density readings will increase where measurements are done correctly, where the instruments are properly calibrated, and readings are occasionally verified. It is useful to have more than one device to determine the density of finished syrup. In Ontario, concentrated cooked sap must have a minimum density of 66.0 ⁰Brix to legally be called pure maple syrup.
If two devices measure a similar density reading in a batch of syrup, then the measurement is likely accurate. Getting two different density measurements will alert the producer that a problem is occurring, but it won’t indicate which device has malfunctioned. A third reliable reading will be required to know which device is faulty.
Photos 5 & 6. Two density instruments are immersed in maple syrup that is destined to become granular maple sugar. The density is 68.4 ⁰Brix (the bubbles should be cleared in this photo). The left stem is a hydrotherm with a built-in thermometer, where the density is determined by the height of the red column above the syrup level on the glass stem. The right is a hydrometer, where the observed value must be adjusted to the temperature of the syrup to determine the density or ⁰Brix. Therefore, a hydrometer also requires a thermometer.
Hydrotherms are commonly used to measure syrup density. A hydrotherm has a built-in thermometer visible as a vertical red column inside the stem. When the top of the red column is equal to the level of syrup on the stem, the density of syrup will be 65.8 ⁰Brix (U.S. manufacturer) and needs to be boiled or concentrated more. Each small line on the paper scale equals 0.2 ⁰Brix. Many producers will boil syrup until the red column is 1.0 ⁰Brix (5 lines on the scale) above the syrup level on the stem to get a better quality syrup having a density of 66.8 to 67 ⁰Brix.
A hydrotherm works best in warm to hot syrup. As syrup becomes cold the hydrotherm floats higher in the syrup, and eventually the point where cold syrup contacts the stem will align below the paper scale. Accurate density readings are not possible with a hydrotherm when the syrup is too cold.
Hydrometers do not have a built-in thermometer. A hydrometer shows the density of syrup directly on the paper scale, however, is not accurate until a temperature correction is made. Neglecting to make the temperature correction is the most common error made by syrup producers using a hydrometer and results in erroneous density readings. Consult the instructions and the accompanying temperature correction chart for accurate density readings.
In the hydrotherm and hydrometer instruments, the paper scale inside the stem can slip, or a crusty residue from dried sugar or scale buildup on the glass can lead to inaccurate readings. The glass housing can crack or break.
Colour grades for syrup
All non-federally registered Ontario maple syrup producers are required to use the colour classifications outlined in Table 4 of O. Reg. 119/11. On the other hand, federally registered producers may use either the newly introduced four colour classes or the existing five colour classes (until December 31, 2016). So, while the federally registered producers have a choice for the next two years, the non-federal maple producers don’t; they can only use the colour classes outlined in O. Reg. 119/11.
Where producers have developed local retail markets, several have voiced their preference to continue using the Ontario Number 1 colour classification to support the ‘buy local foods’ initiatives they have worked hard to establish.
Photo 9. The various colours of pure maple syrup inspire artistic new designs of containers.
Transporting bulk maple sap to the sugar house
Maple sap is commonly hauled by truck in bulk tanks from the sugar bush to the sugar house. We know that fresh maple sap is a low risk liquid, however in the event of an accident or spill along a highway or public road, authorities need to know precisely what the tanks contain. Clearly label ‘Maple Sap’ on each tank. If a spill occurs while en route and highway authorities do not know what the tanks contain, an environmental cleanup may be ordered, with the associated cost sent to the truck owner.
Photo 10. When transporting maple sap, label bulk tanks on the sides or back of each tank as containing maple sap.