Gel Ice Packs & Refrigerants for Shipping — How to Keep Products Cold
Shipping perishable products — food, live cultures, certain cosmetics, pet food — requires understanding how long your insulation system can hold temperature, not just adding ice packs and hoping for the best. The gel pack is only part of the system; the insulated liner, box size, transit time, and ambient temperature all determine whether products arrive in safe condition.
Types of Gel Ice Packs & Refrigerants
Standard gel packs (16 oz / 1 lb)
The most common size — holds 34°F for approximately 12–18 hours in a standard insulated box.
Best for: Single-meal kits, small perishable orders with 1-day transit
Large gel packs (32–72 oz)
Longer hold time — 24–48 hours in well-insulated boxes.
Best for: 2-day perishable shipments, meal kits, raw pet food
Dry ice
Solid CO2 — subzero temperatures for frozen shipments. Sublimates (disappears) in transit.
Best for: Frozen products, ice cream, meat, items requiring 0°F or below
Phase change materials (PCMs)
Engineered materials that maintain specific temperatures (2–8°C, 15°C, etc.) as they melt/freeze.
Best for: Pharmaceutical products, probiotics, temperature-controlled medical supplies
Practical Tips
- •Freeze gel packs solid for 24+ hours before use — partially frozen packs hold temperature for half the time
- •Rule of thumb: 1 lb of gel pack per 1 lb of product for 1-day transit; 2 lbs of gel pack per 1 lb of product for 2-day
- •The insulated liner matters as much as the gel pack — thin foil liners lose temperature 2–3x faster than expanded polystyrene (EPS) foam liners
- •Ship Monday–Wednesday for perishables to avoid weekends in carrier facilities with no temperature control
- •Dry ice requires carrier notification (hazmat class 9) and specific package markings — don't ship dry ice without carrier approval
Frequently asked questions
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