What makes a seed oil good or bad?
In the last few years, seed oils have made headlines for being unhealthy. Is it true? Like most things in life, the story is more complicated.
Most seed oils are made using chemicals.
There are chemicals to dissolve the oil from the solid parts of the seed. Then there are the chemicals to remove other trace components of the oil. The chemicals used aren’t all that appetizing. They include substances like hexane (an explosive byproduct of crude oil refining) and bentonite (the stuff that makes kitty litter absorbent). The chemicals are removed by the end of the process, so you’re not eating hexane beyond possibly a bare trace amount.
But that process also removes good parts of the seeds, like antioxidants. And it removes the flavor too – that’s why supermarket corn oil doesn’t taste like corn on the cob. The result is a bland, pale oil that can be a useful ingredient but doesn’t always have a whole lot of nutrition. It’s not evil, but it’s not brilliant, either.
The process isn’t unique to seed oils. It’s true for many industrially produced fats, including olive oil that’s not graded as “extra virgin” and beef tallow.
But there’s a better way: some seed oils are produced mechanically.
You crush the seeds, then press out the oil; no chemicals involved. (Historically, this is how extra virgin olive oil was made, too. These days, most olive presses have been replaced by centrifuges, but it’s still a fully mechanical – not chemical – process.) In addition to the fat, mechanically pressed oils contain many other good parts of the seed, like color, aroma, flavor, and healthy nutrients. This method is less common than chemical extraction because it costs more. But for small scale producers interested in flavor, like Oliver Farms and Stony Brook, mechanical is the way to go.