I requested pie, specifically a double-crust pie, for Pi Day, and Marie obliged with the Sour Cherry Pie as the weekly Alpha Bakers recipe. That set off The Great Sour Cherry Hunt. Sour or tart cherries, a fruit I'd be pretty unaware of if not for these baking adventures, have a short season (mid-summer) and a restricted cultivation area (Michigan, mostly, and the Pacific Northwest). This helps account for why this Georgia girl (with some sojourns in Texas and Mississippi) has never seen fresh sour cherries in a store. Scheduling this pie way off-season is then not such a problem, because many people aren't going to find the fresh sour cherries at any season.
Then there's the tart cherry concentrate, an optional ingredient to add a punch of cherry flavor. This turns out to be a food supplement item (tart cherries contain a lot of melatonin, among other purported healthful substances), and you can get a 16 ounce bottle for $25 or so of the brand Rose recommends. The recipe wants 2 tablespoons, so unless you have a use for the rest of the bottle, that's a pricey purchase for just the pie. [Postscript: 2 weeks later, I spotted a $9 bottle at Your DeKalb Farmers Market this weekend. Of course.)
Discussion of the search for sour cherries started on the Alpha Bakers' internal Facebook group more than a week ahead of the assigned date, and some people mentioned finding them frozen, presumably a better product than canned. I decided to try to find them and to also look for a tart cherry concentrate at Trader Joe's, and if not there at the nearby Whole Foods. Neither store had the cherries--frozen sweet cherries were available at Whole Foods, but no tart ones in any form but dried. I did pick up a small bottle of sweet cherry concentrate for a mere $5 or so, which I'm sure did not give the same effect as Rose was after, but might be better than no cherry concentrate at all.
I then searched out two other upscale groceries I hadn't used before, Fresh Market and Sprouts, with no better luck. After the stop at Sprouts I moved across the street to a Kroger, where I found cans of tart cherries on special for $1.59 each, and bought 3. The generic canned cherries didn't have great color, but they tasted fine.
In the end I did use all 3 cans of the sour cherries, minus a good handful tossed for cosmetic reasons (black or brown spots, mostly). I drained them well, then added about 1/2 cup of the canning liquid to the filling. That seemed to give an acceptable filling consistency--a little loose, but slices mostly held together. Well, one did, at least. Some of the issues with less pretty pieces may have been with cutting small wedges for those of us who wanted some pie, but not too many calories.
The pastry is the same cream-cheese pastry I had made for the Luscious Apple Pie, which I did before the Alpha Bakers got started. I didn't achieve "flaky" this time (though I did on the Smitten Kitchen white bean and pancetta pot pies for the same meal...that's an all-butter crust), and the nieces said "not our favorite crust" but good. Sister-in-law liked the buttery flavor and the crusty-ness. This was my first attempt at a lattice crust as best I can recall, and it was surprisingly easy--I suspect beginner's luck. I did add "3.1415" for Pi Day on top, but it's pretty well camouflaged by the lattice.
We all liked the sour cherry filling, not so overwhelmingly sweet as a sweet-cherry pie. Sister-in-law took the remains of the pie to school and found at least one person familiar with sour cherry pie and very happy to finish it off with great enjoyment. I think we'll count this as a successful baking project despite the lack of fresh sour cherries.