I attempted to pressure cook olives today in the hopes of creating a process that was quicker than the natural curing method I found which was daily replacement of a brine mixture (water, salt and vinegar) for about 2 weeks.
It was my thought that the bitterness compounds that leach out may be heavy enough that when they're drawn out by the steam they'll be drawn into the pot with the condensate and left behind during the next steam creation cycle.
While this may have been the case, the liquor left behind after the pressure steaming was bitter and had some of the coloring from the olives, they did not have sufficient bitterness removed. In retrospect, pressure steaming was not the most suitable method of testing this theory. Since it suggests that contact time is the most important element, an atmospheric temperature steaming basket with a longer time would probably work better by potentially allowing for greater flow out of the vessel.
The liquor in question reminded me of overbrewed tea (specifically from the bitterness). I'd like to see if it had any health benefits, but I have no idea how to organize nutritional testing or have the capital available to undertake it. I am curious if there would be any use for a concentrated bittering agent. It doesn't have the sweetness of hops, but with a sweetener, perhaps it could be used as a substitute for them.
The pressure cooking time tested was very short as I didn't know how long you can pressure steam before it runs out of water. The total cook time was probably 20 minutes (bring up to temperature, then kill the electricity and let it come down extremely slowly). I suspect based on the remaining liquid that I could probably have run it for about an hour before liquid levels became a problem. The issue is that with a pressure cooker I have no way to check or increase the liquid level.
When examined after steaming the olive skins were very loose fitting, but still in one piece. It's not clear if it was mass lost from the centers or if the skin was merely stretched out by the heat. The centers were fairly liquidy though very bitter. The taste had some similarities to creamed corn or avocado. The latter has prompted me to flag this for further research.
I skinned the olives and left them briefly in a brine, but I neglected water so I ended up with olives that were more sour than bitter. I'm currently soaking them in some water in the hopes of negating both.
The consistency may be useful for development of vegan cheeses or avocado substitutes. while not as environmentally or politically useful as vegan foods, avocado is expensive with prices ranging from $2 to $9 per avocado, compared to about $7 a kilo for olives.
I'm considering repeating this experiment with pre-brined olives like those you get in a store. I wouldn't expect the same results since most canned or jarred foods would be heat/pressure treated for sterility, but I'm still curious about the result.