Hello,
I hope you don't mean literally cooking your oil, but here is some I have made up here at home.
Flax plant growing out back here.
And after harvest.
Seeds threshed & hulled.
Then it goes to the neighbor with the press and comes back like this.
Rendering is next.
Finally, 1 or 2 years standing in a sun exposed windowsill will bleach it nicely.
Three versions:
left, your store bought boiled linseed oil, middle, my cold pressed linseed oil from the press and right, my home processed, home grown linseed oil.
Greetings,
Don Wagstaff