I was amused to see, in my Kleingarten monthly magazine, that they have named the Horneburger Pfannkucher http://pomologen-verein.de/fileadmin/user_upload/Landesgruppen/2016_Horneburger_Pfannkuchen.pdf as their Apple of the Year. I suspect that this is what is growing in my Kleingarten because:
--The apple looks right
--The timing looks right
--The apple is indeed super sour from the tree, and it mellows a bit after storage
--It grows in very marshy ground, which much of my garden is
--My Kleingarten is indeed in the burg of Horn, which is a village that was absorbed by Hamburg
It's a lovely mature tree that I have sadly neglected for a few years. We have not yet pruned it, and we bought the Kleingarten from an elderly couple who probably hadn't pruned it in years either. It bears very heavily. When they say very sour, that is an understatement. It makes fine applesauce, and I've got a couple of boxes in storage (packed in fallen leaves).
My garden neighbor, who is full of opinions, thinks it's a terrible tree, but I'm pretty happy with it.
My terrible translation of the PDF below:
Origin: Collected from town of Horn's Marsh Dam around 1840, discovered and developed by Altland (fruit growing region on the other side of the river Elbe) fruit grower Jakob Köpke in neighboring Neukirchen
Pick in: October
Eat in: November through March
Fruit form: Big to very big fruit, round, often irregular, ridged around the flower
Skin: Shiny to lightly rough, early green, later yellow with red top color
Fruit flesh: Initially hard and very sour, later milder
Tree: Very robust and strong-growing, even in wet moor-like ground, triploid which means no pollen saving?
Distribution: Earlier in the lower (northern) Elbe and the neighboring areas widely distributed, in first place in Altland statistics from 1939
Source: E. Brandt, Of Apples and Men, Fischerhude 2014
Note: Very beloved as a storable baking and sauce apple