Solving maple syrup's sticky situation: knowing when the season ends

Maple syrup season is dripping to an end around the province. But knowing exactly when the season ends has always been a challenge. That's what maple syrup producers are trying to change.

At season's end, sap may taste good, but resulting syrup is bad. So producers are working on a fix

Bob Gray has been making maple syrup for 34 years. He runs a small syrup operation in Kemble, Ont., north of Owen Sound. 'Maple syrup keeps you young. They say sugar makers never die, they just evaporate.' (Haydn Watters/CBC)

The frogs have been noisy night after night — and for Bob Gray, that means maple syrup season is over.

Gray's been relying on the sounds of the spring peeper to tell him when to stop his sap production for a long time now. He runs a small sugar shack in Kemble, Ont., just north of Owen Sound. He knows other syrup makers who look at how high wild leeks are or who listen for the call of woodcocks to determine when the season ends.

"None of these are super scientific," he said. "They may be described as being old wives' tales and sometimes those just aren't as accurate as we think they are."

Maple syrup producers have no precise way of knowing exactly when their season is up and the sap's not good — something known as off-flavour buddy syrup. The sap looks clear, smells good and tastes fine. But it's only when it's been boiled down into syrup that you know it's gone buddy.

Jugs of maple syrup line Gray's home, where he runs Kemble Mountain Maple Products. 'I eat a lot of syrup,' he admits. (Haydn Watters/CBC)

"It's a lot of energy and time and when you get to taste it at the end of that it tastes like burnt Tootsie Roll or even worse," he said. It means lost syrup stock, money and resources.

So members of the Ontario Maple Syrup Producers Association have come together to find a fix.

Syrup producers around the province have been collecting daily test tubes of their saps and syrups. Those will be sent to Fanshawe College in London this spring and analyzed to see if there's a way to predict buddy sap.

To learn more about buddy sap, tap on the audio player below.

"We're just trying to figure out what the chemistry is and what the changes are over the season and if in fact there is a precursor there," said Gray, the association's volunteer research chair.

"It might be an amino acid or it might be something else. But if we can identify that, then we're off to the races. We don't know if it can be done but there's a good chance that it can be done. So we're keeping our fingers crossed."

Results expected this fall

It's groundbreaking work — with big potential benefits for the wider syrup industry in Quebec, New Brunswick, Nova Scotia and northeastern states.

Significant research has been done before, largely by researchers in Quebec and Vermont, two maple syrup giants. But that's come up short — and divided. 

Carleton chemistry professor David Miller is pretty confident they will be able to get an answer this time. Miller started working with Ontario maple syrup producers in 2012, when he came to them with the problem of mould in maple syrup. They came back to him with this problem. So he considers himself the "godfather" of this project.

Gray has been out in his sugar bush, taking samples of his sap on a daily basis this season. He'll send the samples to London, where they will be analyzed over the spring and summer. (Haydn Watters/CBC)

"The level of technology that we can bring here and expertise is uncommon," he said. "There are really smart chemists working on the problem so we will for sure get a picture that will be unique in the world of the metabolome in the sap."

He expects results to come back late this summer or in the early fall.

If they identify what's causing the buddy syrup, they can then work on creating an identifier, like a paper test, that can be used while out in the sugar bush — a lot more scientific than waiting for croaking frogs.

'You're just guessing all the time'

Gray's house is cluttered with bottles of syrup — snaking the length of his dining room.

After 34 years of making maple syrup, he's gotten good at knowing when to halt production come spring. He's learned the hard way, once making 100 litres of buddy syrup by accident, a batch he dubbed "Bud Light."

Gray runs a small operation, with about 700 of these spiles out in his sugar bush. The bush is on a south-facing slope, so sap comes down by gravity into repurposed milk coolers. (Haydn Watters/CBC)

"It shouldn't have happened. If I could have tested the sap, I would have known right away not to do that. You're just guessing all the time."

He's keeping meticulous records for all the sap and syrup he's collected this season, measuring temperature, taste and grade. The difference between just a few days is remarkable; the colour of the syrup darker and much stronger and buddy in taste.

Maple-themed photos and clipped newspaper articles about maple syrup hang on the walls of the Gray's sugar shack, including this photo of their grandson in a syrup bucket. (Haydn Watters/CBC)

At the same time as this research, he's running experiments of his own to see how syrup fares with different variables. He's no chemist though, so he's eager to get something scientifically sound.

"I still go by the frogs, but if they can get a paper test developed, I'll be going with that."


Haydn Watters is a roving reporter in Ontario, mostly serving the province's local CBC Radio shows. He has worked for the CBC in Halifax, Yellowknife, Ottawa and Toronto, with stints at the politics bureau and entertainment unit. He ran an experimental one-person pop-up bureau for the CBC in Barrie, Ont. You can get in touch at