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Dryer best practices

How to dry pellets correctly, what dryers work, and how to avoid the two opposite mistakes: wet pellets (foaming) and overheated pellets (aggregation / cake). Reported across 28+ customer cases.

Why drying matters

Section titled “Why drying matters”

Most pellets — especially PETG, PCTG, and rPLA — are hygroscopic. They absorb moisture from the air, even when sealed. Wet pellets cause:

  • Foamy, bubbly extrusion → see PETG foaming and moisture
  • Popping / crackling sounds during extrusion
  • Poor surface finish and weak layer adhesion
  • Erratic flow that triggers motor skipping

PLA is less sensitive but still benefits from drying when stored long-term.

The drying rules

Section titled “The drying rules”
RuleValueWhy
PETG / PCTG temperature60–70°C (depends on the grade)Hotter dries faster but risks aggregation — back off if pellets pack together
PLA temperature~50°CPLA dries at a lower temperature than PETG
Minimum drying time (PETG)at least 6 hoursLess time = water still trapped inside
Drying time (long-stored or visibly wet)longer / raise temp slightlyIf it still bubbles, leave longer or raise the temperature a little
Gate (guillotine)Closed while drying, open to feedKeep the lower gate closed to dry, then open it so the feeding can draw pellets
Keep dryer ON during the printYesDrying continues while printing; pellets outside the dryer re-absorb moisture

Symptoms of dryer mistakes

Section titled “Symptoms of dryer mistakes”

Pellets too wet (under-dried)

Section titled “Pellets too wet (under-dried)”

Pellets aggregated (over-heated dryer)

Section titled “Pellets aggregated (over-heated dryer)”
  • Pellets stuck together in chunks / cakes
  • Vacuum struggles to suck the chunks (or they get stuck mid-tube)
  • Extruder motor seizes when a chunk reaches the screw
  • Visible: pellets are no longer individual, the surface looks fused / glossy

If you see aggregated pellets:

  1. Empty the dryer immediately
  2. Discard the cake (don’t try to crush and reuse — the polymer has already started to degrade)
  3. Lower the dryer setpoint before refilling (if PETG was aggregating)
Section titled “Recommended dryer types”

What works

Section titled “What works”
  • Performance / production: industrial hopper dryers with an active drying system (molecular sieve or rotating drum) — Moretto mini dryers, or New Omap (https://newomap.com/), e.g. the WD.E 15÷30 series. ~20 kg capacity is plenty (the G1 prints ~2 kg/h max)
  • Entry-level: the Ginger Additive D1 for PETG and PLA — https://www.gingeradditive.com/products/ginger-dryer
  • Modified spool dryers can work as a low-cost option but are slower and capacity-limited

Spool/filament dryers used for pellets

Section titled “Spool/filament dryers used for pellets”

Small spool dryers (designed for filament) can be used for pellets but have significant limitations — the airflow is designed for flat spools, not pellet masses. At least 2 customers have reported that spool dryers require 2–3× longer drying times compared to dedicated hopper dryers to achieve equivalent results. If you only have a spool dryer, double the stated drying times and verify pellet moisture with a test extrusion before printing.

What doesn’t work well

Section titled “What doesn’t work well”
  • Standard household ovens — uneven temperature, hard to keep at 65°C exactly, risk of aggregation
  • Filament dryers for spools — designed for filament, low pellet capacity, poor airflow

Capacity guidance

Section titled “Capacity guidance”
  • ~20 kg is more than enough — the G1 prints at most ~2 kg/h, so even a long job will not outpace a 20 kg dryer
  • The Ginger D1 holds ~25 kg

Contact Ginger Additive support for current dryer recommendations and supplier links.

Drying workflow

Section titled “Drying workflow”

Standard cycle (PETG, rPLA, PCTG)

Section titled “Standard cycle (PETG, rPLA, PCTG)”
  1. Load pellets into the dryer
  2. Set temperature to 60–70°C for PETG (depends on the grade)
  3. Keep the lower gate closed while drying; open it once dry so the feeding can draw pellets
  4. Run for at least 6 hours
  5. Leave the dryer ON during the print; start printing straight from the dryer — don’t let pellets sit in open air

Still bubbling after drying

Section titled “Still bubbling after drying”
  1. Leave it longer, or raise the temperature slightly
  2. Test extrude on a skirt
  3. Still foamy after extended drying? The batch may be degraded — replace from a fresh sealed bag

PLA

Section titled “PLA”
  • PLA dries at ~50°C
  • For batches stored open or in humid environments, dry longer

Avoiding aggregation in the dryer

Section titled “Avoiding aggregation in the dryer”
  • Verify the dryer’s own thermostat — some run hotter than the displayed setpoint
  • Don’t fill the dryer to its absolute max — pellets at the bottom heat unevenly
  • Stir / rotate the contents if your dryer doesn’t have airflow circulation
  • Watch the pellets the first hour — if you see surface gloss developing, lower the setpoint

Storing dried pellets

Section titled “Storing dried pellets”
  • Avoid leaving pellets in open hoppers between prints
  • For long pauses, put the pellets back in the dryer before resuming

Notes

Section titled “Notes”
  • Pattern observed across 28+ customer cases, often combined with PETG foaming and moisture
  • Customers regularly default to “if more drying is good, hotter must be better” — push back: the limit is aggregation, so for PETG keep within ~60–70°C and back off the moment pellets start packing together
  • A common compound failure: aggregated pellets fed to the extruder cause Hopper suction problems (vacuum can’t move them) and then Extruder motor skipping (chunks jam the screw)
Section titled “Related notes”