Hot Fill vs. Cold Fill: Which Works Best for Your Squeeze Tube Formula

Hot Fill: Definition and Process

Hot fill is exactly what it sounds like: the product is heated to a high temperature (typically 65°C to 85°C / 150°F to 185°F) and then filled directly into the squeeze tube while still hot. The tube is then capped and cooled rapidly.

How Hot Fill Works

1. Heating – The formula is brought to a temperature that kills microorganisms.

2. Filling – The hot liquid is dispensed into the tube.

3. Capping – The tube is sealed immediately.

4. Cooling – As the product cools, it contracts, creating a slight vacuum that pulls the tube walls inward slightly. This vacuum reduces headspace oxygen, preserving the formula.

Best Formulas for Hot Fill

• Anhydrous balms (body butters, hair waxes)

• Honey-based products

• Acidic formulas (pH below 4.5)

• Products with heat-activated preservatives

• Lip balms and solid sticks (filled into tube form)

Advantages of Hot Fill

Preservation without harsh chemicals – The heat itself sterilizes the formula, allowing you to use milder preservatives or even none at all.

Extended shelf life – The vacuum seal created during cooling reduces oxidation, keeping oils and butters fresh longer.

No need for secondary sterilization – Your squeeze tube doesn't require pre-sterilization if the hot fill temperature is high enough to sterilize the tube interior during filling.

Better for thick formulas – Hot fill reduces viscosity temporarily, making it easier to pump thick balms into a custom squeeze tube without air pockets.

Disadvantages of Hot Fill

Material limitations – Standard PE tubes deform above 85°C. Laminated tubes (with aluminum or EVOH barriers) handle heat better but cost more.

Cooling time – Hot-filled tubes require longer cooling tunnels, slowing down your production line.

Not for actives – Vitamin C, retinol, benzoyl peroxide, and many botanical extracts degrade rapidly at high temperatures.

Cap stress – Heat can warp caps or soften hinge mechanisms on flip-tops.

If your formula contains heat-sensitive actives, hot fill is likely not an option.

Cold Fill: Definition and Process

Cold fill (also called ambient fill) is the standard method for most modern cosmetic formulas. The product is manufactured at room temperature or slightly warm, then filled directly into the squeeze tube without applied heat.

How Cold Fill Works

1. Preparation – The formula is mixed and cooled to room temperature (or kept at a stable ambient temperature).

2. Tube sterilization – The wholesale squeeze tube may be pre-treated with UV light, gamma radiation, or chemical sanitizers.

3. Filling – A nozzle inserts into the tube and dispenses the formula.

4. Capping and sealing – Induction sealing or simple capping closes the tube.

Best Formulas for Cold Fill

• Water-based gels and cleansers

• Emulsions (lotions, creams, sunscreens)

• Fermented or probiotic products

• Vitamin C and retinol serums

• Enzyme-based exfoliants

Advantages of Cold Fill

Preserves active ingredients – Heat-sensitive actives remain fully potent. This is non-negotiable for clinical skincare brands.

Faster production speeds – No heating or cooling tunnels mean your filling line moves faster.

Wider material compatibility – Almost any custom squeeze tube material works with cold fill, including standard PE and clear tubes.

Simpler quality control – One variable (temperature) removed from the process means fewer things can go wrong.

Disadvantages of Cold Fill

Requires preservatives – Without heat sterilization, your formula needs an effective preservative system to prevent microbial growth.

Separate tube sterilization needed – The squeeze tube itself must be sterilized before filling, adding a step and cost.

No vacuum seal – Cold-filled tubes don't create a natural vacuum, so oxidation risk is higher unless you use nitrogen purging or oxygen scavengers.

Higher risk of recontamination – If your filling environment isn't sterile, cold-fill exposes the formula to airborne microbes.

For water-based formulas with active ingredients, cold fill is usually the only safe choice.

Side-by-Side Comparison: Hot Fill vs. Cold Fill

How Tube Material Affects Your Choice

Not every squeeze tube can handle hot fill. Here's what you need to know.

Standard PE Tubes

• Heat tolerance: 50°C – 70°C

• Hot fill compatible? Limited (low-temp hot fill only, below 70°C)

• Best for: Cold fill only for most formulas

Laminated Tubes (Aluminum or EVOH barrier)

• Heat tolerance: Up to 90°C

• Hot fill compatible? Yes

• Best for: Hot fill of balms, pharmaceutical creams, and oxygen-sensitive products

Custom Squeeze Tube with Thick Walls

• Heat tolerance: Varies by wall thickness (0.4mm – 0.8mm)

• Hot fill compatible? Possible with engineering

• Note: Thicker walls resist deformation but cool slower

If you are ordering wholesale squeeze tube from a stock supplier, assume it is standard PE and only suitable for cold fill unless specified otherwise. For hot fill, you will likely need a custom squeeze tube made from laminated material.

Cost Implications for Wholesale Buyers

Your choice of filling method directly affects your unit cost.

For a wholesale squeeze tube order of 50,000+ units, cold fill with standard PE is usually the most economical route. However, if your formula allows for hot fill, you may save on preservatives and gain a longer shelf life — potentially worth the higher tube cost.

Which Method Is Right for Your Squeeze Tube?

Use this decision tree to guide your choice.

Choose Hot Fill If:

• Your formula is anhydrous (no water)

• Your formula has a pH below 4.5 or above 10

• You want to avoid synthetic preservatives

• You are filling balms, waxes, or honey-based products

• Your custom squeeze tube is laminated or high-temp PE

Choose Cold Fill If:

• Your formula contains water

• You use heat-sensitive actives (retinol, vitamin C, enzymes, probiotics)

• You are using a standard wholesale squeeze tube (stock PE)

• You need fast production turnaround

• You already have an effective preservative system

Hybrid Approach (Warm Fill)

Some manufacturers use a middle ground: warm fill at 40°C – 50°C. This is not hot enough to sterilize but reduces viscosity slightly for easier pumping. It works for some emulsions and lotions but offers few of the benefits of true hot fill. Use this only if your contract manufacturer recommends it.

Common Mistakes to Avoid

• Mistake 1: Hot filling a standard PE tube
  Result: Melted, deformed, or burst tubes. Always confirm heat tolerance with your supplier.
• Mistake 2: Cold filling an anhydrous balm
  Result: Air pockets, uneven fill, and difficulty dispensing. Thick balms need heat to flow properly.
• Mistake 3: Ignoring tube sterilization
  Result: Microbial contamination, mold growth, and a costly recall. Even cold-filled tubes need pre-treatment.
• Mistake 4: Assuming all custom squeeze tubes are heat-resistant
  Result: Paying for custom tooling but still getting a tube that deforms. Specify heat tolerance in your technical drawing.

Final Verdict

There is no universal winner. The best filling method depends entirely on your formula and your squeeze tube material.

• For water-based skincare with active ingredients: Cold fill is the only safe choice.

• For anhydrous balms and waxes: Hot fill offers better preservation and shelf life.

• For most indie brands starting with a wholesale squeeze tube: Cold fill with standard PE is the most accessible, cost-effective path.

Before committing to a custom squeeze tube order, run a small-scale fill test with your chosen contract manufacturer. Fill 50–100 tubes using your intended method, then test for stability, dispensing performance, and microbial safety over 4–8 weeks. The data from that small test will save you from a large-scale mistake.