Can I make pesto in a blender? Will it have the same results as a food processor?

cav, i've never read that before. does that mean making evoo vinaigrettes in a processor-turns out bitter taste?
i've been making processor vinaigrettes for 40 years(part canola, part evoo) but i've never been aware of any bitterness. thx.

It's an old claim that's been circulating cooking forums for years that was amplified by this information (unsupported hypothesis, really) from Cook's Illustrated regarding bitter mayo made in a food processor: https://www.cooksillustrated.com/how_tos/5475-testing-olive-oils-bitter-end, but they specifically exempt pestos because the greens used to make them are inherently bitter. Unlike mayonnaise, the greens used to make pestos (basil, arugula, etc) are chock-full of bitter polyphenols. Additionally, SeriousEats tried to put this to the test (https://www.seriouseats.com/2018/06/does-blending-olive-oil-make-it-more-bitter.html) and debunked it, finding that blind taste testers couldn't tell the difference between blended/unblended olive oils and the most likely culprit influencing the perception of bitterness was actually garlic. Apart from that, Basil (the green most often used in traditional pestos) can sometimes be extremely bitter if the leaves are picked from a plant that was allowed to flower (this is why you should always pinch off budding basil flowers), and there are some varieties of basil that are just bitter in general; even beautiful smelling/looking fresh basil can be uncharacteristically bitter depending on how it was grown and harvested.

Personally, I've never made a bitter pesto, but my go-to preference is a spicy olive oil and lemon arugula walnut vegan pesto I fully emulsify in a Vitamix (I make a cup of this at least once a week, it goes on everything, and is seriously addictive). IMO, it's all ingredient quality and ratios, but the likeliest source of bitter pesto would be poor ingredients in the form of rancid fats, greens that are starting to rot, raw garlic, or overmixing without introducing an acid to tone down the polyphenols. My money is on the fats (olive oil or nuts), because rancid fats are inherently quite bitter and if you shop at groceries that don't have a high turnover of oils and nuts (e.g., buying a bag off a shelf instead of from a bulk bin), it can be really hard to get nuts and oils that *aren't* already rancid. If you are like me and can taste fat rancidity (or smell it from a mile away) and are sure that's not the issue, then try adding some fresh lemon juice to your recipe (I always use equal parts olive oil and lemon with some nutritional yeast, but I would probably use less acid if making a pesto that contained cheese). If you don't have a sensitive palate, you should at least be able to taste and *enjoy* your olive oil and nuts outright; if you wouldn't be satisfied to eat them in large quantities with some plain bread, then they're never going to taste good in something like a pesto. Another way you can try to counteract bitterness is with sweetness, which you can do by roasting the garlic; loosely wrap your cloves (they should be separated/loose with skins on so they cook quickly and steam in their skins without burning) in some aluminum foil and bake it in a toaster oven at around 350 for about 10-15 minutes, then smoosh the roasted cloves out of the skins and throw your delicious roasted garlic in the blender.

How well would palm oil work with it?