Cherry Pie Day

What the day is

Cherry Pie Day is observed on February 20. The choice of cherry decides the pie before any pastry is involved.

Origin and background

There are two distinct species in play. Sweet cherries are the ones sold to eat out of hand, firm and mild. Sour cherries, sometimes called tart or pie cherries, are a different species, softer, markedly more acidic and rarely sold fresh because they bruise quickly and few people enjoy them raw. Almost all of the American sour cherry crop is grown for processing, and Michigan produces the bulk of it.

Sour cherries make the better pie for a reason that survives cooking. Heat and sugar flatten delicate flavors, so a sweet cherry that tasted good raw arrives bland and slightly cloying once baked, while the acidity of a sour cherry holds its shape against the sugar and reads as intensely cherry. This is why a pie made from expensive fresh sweet cherries is so often a letdown, and why tinned or frozen sour cherries produce a better result than the fancier fruit.

The structural problem in any fruit pie is water. Cherries release a great deal of it, and the filling must be thickened or the base turns to paste. Cornstarch sets firm and clear but breaks down if boiled hard or held too long. Tapioca tolerates freezing and long baking better and gives a glossier set. Flour is the most forgiving and the cloudiest. Whichever is used, the filling needs to actually reach a boil for the starch to activate, which is why a pie pulled out as soon as the crust colors frequently runs.

The traditional almond note in cherry desserts is not an accident of fashion. Cherry stones and almonds are botanically close relatives, and the aroma compound overlaps.

How to take part

• Use sour cherries, frozen or tinned, rather than fresh sweet ones.
• Let the filling bubble properly so the starch sets.
• Add a little almond extract, which is the traditional pairing for a botanical reason.
• Cut vents generously. Cherry filling boils over enthusiastically.
• Cool it completely before cutting, or it will run whatever you thickened it with.