Everyone around here loves pesto. Much like the marinated peppers, pesto sauce has become a staple in our home. I make a batch every time my pots of basil are green and luxuriant again, and right now they’re growing wild. While I stick to my favourite pesto sauce recipe for it (from Ina Garten’s Barefoot Contessa Back to Basics), sometimes I wonder why my sauce is a tad bitter. I wonder if the nuts might have been bitter, and leave it at that without probing into the issue.
Just recently I discovered I was wrong about the poor nuts! The olive oil is the culprit here.
I stumbled upon the explanation for this on DelciciousDays.com, which in turn comes from Cook’s Illustrated:
“Extra-virgin olive oil contains bitter tasting polyphenols coated by fatty acids, which prevent them from dispersing. If the oil is emulsified in a food processor, these polyphenols get squeezed out and the liquid mix turns bitter.
The magazine further claims this is only a problem when mixing dressing or mayo, because in pesto the other ingredients as nuts and cheese are robust enough to cope with it. This is where I (Nicky) disagree; I rarely prepare pesto with extra-virgin olive oil in the food processor anymore – because of the indeed noticeable bitter outcome”
Who would have thought?
So anyway – now that we can’t put olive oil into the food processor, I added 1/4 cup water (just enough to keep it running) until it formed a thick paste. Once the paste was ready, I stirred in the olive oil and parmesan cheese. Voilà! No more bitter pesto!