Every autumn, apples are widely harvested in the Czech Republic. Drying apple slices is a great way to preserve them. Czechs call this healthy snack Křížaly.
Peel 4 pounds apples and trim away any bruised spots.
Remove the cores: set each apple stem side down on the board and press the apple corer straight down through it. Without a corer, quarter the apples and cut out the cores.
Slice the apples into even rings, ⅛ to ⅙ inch (3–4 mm) thick.
Optional: dip the rings briefly in a bowl of cold water mixed with 2 Tablespoons lemon juice, then let the excess drip off.
Arrange the rings on the dehydrator trays in a single layer, close together but not touching. If using ground cinnamon, dust the rings very lightly now.
Dry at 150 °F for 8 to 12 hours, swapping the trays around once or twice. About 8 hours gives soft, juicy rings for eating within days; 10 to 12 hours dries them fully for storage.
Check before turning the dehydrator off. A done ring bends without breaking and releases no drops of juice. Let the rings cool completely.
Notes
Storage: store fully dried rings in an airtight glass jar in a cool, dark, dry place; they keep until the next harvest. For the first week, shake the jar once a day; if the glass fogs up, dry the batch one more hour.
Oven method: lowest setting, about 150°F (65°C), rings on wire racks, oven door slightly ajar, 5 to 8 hours. Serving: one serving ≈ a small handful, 1 oz / 25 g
No kitchen scale? One medium apple weighs about 6½ oz (180 g); 4 pounds is roughly 10 medium apples