In earliest regions of southwestern Ontario, the maple syrup production season will draw to a close soon.  Unseasonably cold weather has helped to slow bud development and prolong sap flow over the previous two weeks, however the increasing day length and intensity of the sun has warmed branches and buds.  Buds on maple trees are swelling and elongating and bud break will soon occur.  Prince Edward County reported buddy off-flavours have begun on April 4th and sap harvest has ended there for the season.

Early areas, commercial producers who use modern vacuum collection for sap harvest are reporting very good yields of high quality syrup this year.  A few producers exceeded the provincial average of 1.1 litres syrup per tap.

In Grey / Bruce Counties, producers continue to collect fresh sap and boil new syrup. The yield so far averages 55 to 80 percent of the 2018 syrup crop processed.  Sap sugar concentration ranged from 1.9 to 2.2 ⁰Brix this past week and sap remains clear.  Most producers have made Amber and Dark syrup with a few reversions back to Golden for unknown reasons.  Maple flavour is described as excellent this year.  Syrup has been very clear and filtering not a problem.

Central Ontario and mid-season areas are reporting a range of syrup processing so far, from Haliburton over to Ottawa and eastern Counties. Many sugar bushes have been frozen this past week due to deep freezing night-time temperatures, and therefore little to no sap flow.  Syrup yields range from 30 percent to 90 percent processed so far with a few surpassing 1.1 litres per tap in the eastern counties.  Firewood supplies are used up now at several wood-fired operations.

Many areas across southern Ontario received fresh snow on Friday April 6

Late season regions, north of Parry Sound, Bancroft, Ottawa Valley and including Thunder Bay, have had a moderate start to their syrup processing season. Producers near Whitney report several runs of sap so far and 25 percent syrup crop is tallied, however the sugar bush has been frozen solid for much of the past week.  New snow has fallen in northern areas, which will help slow down bud development for at least a couple more weeks.  Producers report 20 to 40 percent of a syrup crop has been boiled so far and the season is still young.

Sap flow forecast

The weather forecast for mid and late season areas in Ontario tells that sugar bushes will remain frozen for the weekend, followed by good thawing sap flow conditions for the coming week.  Significant quantities of sap should flow in many areas during the second week of April.  Hopefully the thawing trend will be for a slow transition from winter to spring.  Buds on maple trees will remain dormant for several weeks yet in northern regions.

 Birch syrup season

Producers making birch syrup can be preparing their sap tubing or buckets for the approaching sap flow season.  Birch sap typically begins to flow as maple sap harvest ends, which is convenient for producers who make both maple and birch syrup.

Advanced understanding of birch syrup harvest and processing resides at the University of Vermonts’ Proctor Maple Research Station, as well as Yukon and Alaska, where studies and commercial production have been underway for several years.

 Measuring maple syrup density

Measuring the density of maple syrup is an important step, to achieve the minimum legal density of 66.0 ⁰Brix (in Ontario), to produce a quality maple syrup product and, to help minimize the incidence of spoilage mould by removing as much available free water as possible from the syrup while maintaining quality.

Density measurement is done using various methods and technologies.  Hand-held refractometers, floating hydrometers and hydrotherms, and portable electronic density-measuring equipment are all utilized to measure density, each producer having their own preference.

Regardless of choice, the measurement equipment needs to be trustworthy for the producer.  Producers need to know that maple syrup has reached the minimum legal density of 66.0 ⁰Brix.  Beyond the legal minimum density, many producers will boil to 67.0 ⁰Brix to achieve a slightly thicker texture and mouth-feel to the syrup for their customers.

Ideally, the manufacturer should certify that each device has been tested and calibrated accurately.  Hydrometers and hydrotherms can become inaccurate if the graduated paper scale that is sealed inside the glass slips to a new location, out of calibration and unknown to the producer.

Over the past few years, some producers and judges of maple competitions are investing in electronic density measurement equipment.  Electronic readings are fast with less clean up required.  They can be calibrated by the producer whenever necessary and the accuracy can be quickly verified using laboratory certified solutions of known densities.  There are several models available.  Reputable manufacturers certify their instruments as accurate for the intended purpose and offer fast service if required.

It is important to read and understand the operating instructions for electronic density equipment. Where an electronic instrument is certified as accurate, the manufacturer still requires the unit to be calibrated, that is, to be ‘Zero Brix Set’, before each daily use.  The producer needs to define what 0.0 ⁰Brix equals, otherwise it will not know.  Distilled water measures zero ⁰Brix and is often used to calibrate electronic equipment.

The portable density reader, Misco was used as an example in this article without the intent of endorsing one electronic model over another model.