Fix this batch

One symptom per page, with the likely causes in order and the fix for each.

• Symptom

  Food isn't fully dry — especially on the center trays

  Why center-tray food comes out cool, flexible, or dark in the middle — and the checks that fix it, in the order to try them.

• Symptom

  Candy is chewy, melted, or didn't puff

  Chewy centers, melted puddles, or candy that never puffed — each failure has a distinct cause: spacing, settings, or a candy that fundamentally won't work.

• Symptom

  Rehydrated food is tough, mushy, or tastes flat

  Rehydration failures trace back to three places: how the food was dried, how it's being rehydrated, and what that food can ever be again. Sorting them out — with the food-safety rule that applies.

• Symptom

  Stored food went soft, stale, or off

  Freeze-dried food that went soft, stale, or off in storage failed at one of five points: dryness, packaging, absorber, seal, or environment. Find yours.

• Symptom

  Machine shows a vacuum error or won't pull down

  A vacuum error means the chamber can't reach or hold pressure. Here's the leak hunt in order of likelihood: door gasket, drain valve, hose, then pump.