Candy is the strange corner of freeze-drying: most of it barely contains water, so you’re not really drying it — you’re using vacuum and heat to restructure sugar. That’s why candy runs take hours instead of a day, and why its failures look different from food failures. Match your symptom below.
Symptom: puffed but chewy in the center
Cause: crowding. Candy needs room to expand — often to several times its size — and pieces that touch or sit too densely can’t fully puff, leaving dense, chewy cores. Fix: space pieces with clear gaps on every side, run fewer pieces per tray, and add extra dry time (candy-mode presets commonly include ~2 hours; more is fine). Halving large candies (marshmallows, taffy) also shortens the path the trapped gases need to travel.
Symptom: melted into a puddle or fused to the tray
Cause: too much heat for that candy, or the wrong candy. Widely-shared candy-mode settings run warm and fast — no deep pre-freeze, fast dry, final temperatures around 145 °F — and low-melt-point candies can slump before they set. Fix: use silicone liners or parchment so a partial melt isn’t a cleanup disaster, try a colder start (pre-freeze the candy overnight and skip straight into the cycle frozen), and reduce dry temperature. Some losses are informational: they’re telling you that candy isn’t a candidate.
Symptom: never puffed at all
Cause 1: not enough sugar-trapped moisture to expand. The puff comes from tiny amounts of water and gas expanding inside softened sugar under vacuum. Hard candies with essentially zero moisture sometimes shrug off a standard cycle. The community fix for stubborn hard candy (peppermints are the famous case) is to warm it in a low oven until it just begins to soften before it goes in — softening the sugar matrix so it can expand.
Cause 2: the candy is fighting you chemically. High-fat chocolate barely changes (fat doesn’t sublimate), and heavily acid-coated candies behave unpredictably — sour coatings are a known trouble category. Fix: test one tray of a new candy before committing a full batch, and keep a per-candy log of settings that worked. Our Batch Log has a notes field for exactly this.
The reliable-candidates shortlist
Community consensus is strong that high-sugar, low-fat, slightly-moist candies puff best — think gummies, taffy, marshmallows, and hard-shelled chewy candies — while high-fat chocolates and some acid-coated sours disappoint. Treat any new bag as an experiment: one tray, logged settings, then scale.
Selling your candy? Water activity, labeling, and state rules apply even when the input was store-bought — start with our cottage selling guide.