Some of the unharvested canola that overwintered in 2019-20 was worth harvesting and processing based on research led by Véronique Barthet, the program manager for oilseeds with the Canadian Grain Commission’s (CGC) Grain Research Laboratory.

Véronique Barthet.
photo: Supplied

“Grain handlers and processors had concerns about free fatty acid levels in overwintered canola crops,” Barthet said in a CGC release. “We were able to determine that some of these samples could still be processed into good-quality oil as long as they’re processed as soon as possible.”

Barthet noted in an interview Dec. 16 that just as canola quality varies every year when harvested in the fall, quality also varies with overwintered canola.

“The results for this year are for this year,” she said.

Why it matters: Canola that stays out all winter isn’t necessarily a writeoff, but it’s best to process it as quickly as possible after it’s harvested in spring to avoid further deterioration in oil quality.

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Based on 100 samples collected mostly from northern Alberta, Barthet found overwintered canola had higher oil and free fatty acid content compared to canola harvested in the fall of 2019.

More oil is a good thing, but free fatty acids are not. The latter contribute to stored canola oil going rancid more quickly and heated oil smoking at a lower temperature.

Free fatty acid levels rise after canola seeds start the germination process, which occurs when mature seed is exposed to moisture.

“Free fatty acid is like salt in soup — you can manage it up to a certain point and then you cannot,” she said.

The overwintered canola’s higher oil content wasn’t caused by overwintering, Barthet said. Normally canola from northern Alberta has more oil because of cooler growing temperatures, she said.

“Also the longer you leave the seed out the longer time it has to mature and produce oil. So it’s kind of a combination of the two,” Barthet said.

The samples Barthet collected broke down into the following grades:

No. 1, 27.4 per cent; No. 2, 34 per cent; No. 3, 20.8 per cent and Sample, 17.9 per cent.

Barthet and her team reanalyzed free fatty acid content after the samples were stored for two months and found levels had gone up, even though the canola was stored in low-moisture conditions. That’s why Barthet recommends overwintered canola be processed as quickly as possible.