You know what the great thing is about making a pesto out of pistachios instead of pine nuts? It takes much longer for it to get all brown and gnarly looking because the vibrant green of the pistachios hides the quick oxidation of the basil. So it can keep for two weeks or longer in the fridge before it starts looking unappetizing. That's on top of the fact that it just tastes better...but I might be a little biased since pistachios are my favorite nut, followed closely by cashews, then walnuts.