By: Matt McIntosh
Cleaning, crushing, and bottling one of Canada’s most abundant crops.
How does a bright yellow flower turn into a versatile culinary ingredient? For canola – one of Canada’s most widely grown crops – it starts with a good squeeze.
As the canola plant matures, its yellow flowers develop into pods, containing tiny black seeds. Similar to other plant-based oils, canola oil is made by crushing canola seeds. There are two main methods of crushing canola.
What is canola?
Canola was bred from a similar oilseed crop (rapeseed) during the 1960s and 1970s. The bright yellow flowers of canola plants develop into pods containing canola seeds, with each of the tiny black seeds being comprised of approximately 45 per cent oil.
Today, the crop is grown in many parts of the world, including Europe, North America, and Australia. In Canada, canola constitutes one of the largest field crops, and is particularly abundant in the Prairie provinces.
1) The standard method
The most commonly employed method of crushing canola involves quite a few stages, the first being the removal of weed seeds, plant stalks, and other macro-sized debris which might have mixed with canola as it was being harvested. Next comes flaking – rolling canola seeds to gently rupture the outer coating – and heating, both of which make it easier for oil to flow out of the seeds at crushing. The temperature is carefully controlled to maintain the oil quality.
Crushing is the main attraction. A series of presses are used to squish most of the oil out of the seeds. The now mostly dry seed matter is exposed in a closed system to a food safe solvent to remove oil not extracted at crushing. A common process in many types of plant oil processing, the solvent is then removed and reused.
Though useful in its raw state, processors next use a number of methods (including natural clay filters, water, organic acids, and steam) to remove unpleasant odours, any remaining fine particles, and other unnecessary compounds – while simultaneously improving the shelf life, colour and flavour of the end product.
From here, canola oil can be bottled as a cooking ingredient. However, both the oil and the leftover solids (known as “canola meal”) can also have a variety of other uses – from feed for animals to consumer goods like biodegradable alternatives to plastics.
Why people like cooking with canola oil:
- High smoke point (it doesn’t burn at low temperatures)
- Versatile, neutral flavour
- Long shelf life at room temperature
- Low in saturated fats, and no trans fat
- Contains plant-based omega-3 polyunsaturated fatty acids
2) Cold, double, and expeller processing
A smaller proportion of Canadian food processors do not use solvents, or even heat in some cases, though initially removing weed seeds and other debris remains an important initial step.
“Cold press” systems, for example, extract oil by mechanical means only. Limiting friction and avoiding raising the temperature in such systems is accomplished by pressing seeds slowly. “Double” or “expeller press” systems are similar, though the canola seed is pressed a second time to extract more oil.
Compared to the standard processing method, both cold and double/expeller pressing leaves more oil within the leftover canola meal – something beneficial for those looking to use by-products of the oil making process which feature a higher energy content.
Ensuring Quality
High quality canola oil is neutral in flavour, as well as clear and consistent in colour. To achieve this, processors must consistently meet all the standards in the steps of processing canola oil to ensure quality and longevity of the final product.
In other words, getting the recipe just right, ensures canola oil can last on the shelf or in your pantry for a long time – and taste good.
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