The seeds are cracked, flaked, then cold-pressed at temperatures below 95 F (35 C.) Then it is filtered.
After being pressed for oil, the seeds can be used as livestock feed.
To some, Flax Oil has a rich and nutty taste; others say its taste is as appealing as wet grass. Some brands, in fact, market their oil as “not having a grassy taste as other flax oils do.”
The taste can vary depending on what variety of flax the seed for the oil came from. The taste comes through even in what you put it in, despite other ingredients.
In any event, an acrid or harsh aftertaste indicate that it’s gone off. Dispose of, don’t even feed to animals.
The use of Flax Oil in cooking has not been traditional. It was used more to make linseed oil, for non-food uses such as in paints and varnishes. When it dries, it seals surfaces, so farmers would coat implements in storage with it to help prevent their going rusty.
Linseed oil is processed at high temperatures with steam. This makes it better as a surface-finishing oil, as it will dry harder on surfaces. Some, though, is cold-pressed for fine art use — it doesn’t yellow as much as the painting ages. An alkali added to reduce the acidity of the oil, then it is cleaned with solvents.
Cooking Tips
Best not heated, or at least not heated to above 300 F (150 C). It is fine in use in baking, though (as the baked good never gets as hot as the air in the oven.)
Storage Hints
Some brands may say good for up to 4 months from pressing; some may say 1 year. The difference is owing to different manufacturing techniques.
Refrigerate after opening bottles, and use up within 6 weeks.
The oil needs to be stored in a container which doesn’t let light in, and it needs to be tightly covered. It is best to buy in small amounts, because it goes off so quickly despite all your precautions
History Notes
A man named Frederick Walton invented “Linoleum” (from two Latin words, “linum” meaning “flax” and “oleum” meaning “oil”) in England in 1863. He allowed linseed oil to oxidize by simmering it, which thickened it into “linoleum cement.” He then stirred in pine resin and powdered wood, and spread it on jute for backing. Patterns were introduced later in the 1800s by a Scotsman named Michael Nairn.