Blueberry "Pie"

My girlfriend's mother acquired blueberries in massive quantities recently, and determined that a pie should be made. Generally interested in trying new things, I offered to bake one, and dug out the America's Test Kitchen binder again. The recipe I used was as follows:

6 cups blueberries
~1 cup sugar
4 tablespoons instant tapioca
2.5 teaspoons fresh lemon juice
1/4 teaspoon ginger
pinch of nutmeg
double pie crust
2 tablespoons butter

Now, first of all, it should be noted that cooking in my in-laws' kitchen is always an experiment in substitutions, because (1) things you think you have always turn out to be several years old and (2) the nearest store is kind of a haul, so you only want to make the trip once (and ideally not at all). So I used instant tapioca when I would have rather had potato starch, and the tapioca wasn't really the greatest quality nor particular easy to crush, which was a large factor in the end result. I also realized right as I came to need it that I had no lemon zest, so extra lemon juice was used, which probably didn't help. Lastly we couldn't find the allspice that everyone was quite sure we had, so I wound up faking it with ginger and hoping it worked out.

As it turned out, six cups of blueberries was way too much for a nine-inch pie. I would have been better served with five cups, perhaps even four and a half. Also, the tapioca didn't really dissolve all that well, giving the whole affair a somewhat grainy texture. And we made the mistake of serving the thing that night, instead of giving it time (and, ideally, chilling it). So what we wound up with was really more of a cobbler in a crust.

Now, the good news is the flavor was excellent, and once the half that we didn't get in to was allowed to chill, it more or less became pie-like. Still, I'm looking forward to trying it again with proper ingredients.