Pesto -- frozen into ice cube trays and socked away in the freezer -- is one of my key strategies for preserving basil, arugula, mint, dandelion greens, and pretty much any other flavorful green. But while I can get all of those greens (and cheese) locally, the nuts and olive oil that are indispensable in pesto are harder to find from known sources.
Therefore, the growth of "pine nut mouth," wherein pine nuts cause a bitter metallic taste in the mouth starting 1-3 days after consumption, and lasting up to a week. I experienced such a condition myself several weeks ago, and while it dissapated after several days, it not only took much of the joy out of eating and drinking anything, but has made me anxious about making dishes featuring pine nuts in the future.
What to do? Well, much of this phenomenon seems to be associated with nuts from China. The latest batch of nuts I bought from Trader Joe's says the nuts are a product of "Korea, Russia, or Vietnam," so perhaps I will fare better this time around. Also, for pesto at least there are other nut options, such as the Arugula-Walnut pesto I recently made with excess arugula from the farm. Almonds and cashews also work reasonably well as pine nut replacement options, in my experience.