Before you pick a preform, pick how the product is filled — because the filling technology dictates the neck finish and the resin. Specify the wrong combination and you get a deformed neck, a leaking cap, or off-taste. Here is the buyer’s short version.
Cold fill (ambient / chilled)
The default for still water, CSD and most beverages: product goes in at ambient or chilled temperature, so the neck sees no heat stress. Standard PET resin and standard finishes apply — 29/25 for still water, PCO 1881 for carbonated. This is the lowest-cost, highest-speed route and covers the bulk of Delta’s range.
Hot fill (≈ 85 °C+)
Used for juices, teas and sauces pasteurised in-bottle. The hot product would distort an ordinary neck, so hot-fill demands a crystallised (heat-set) neck and a bottle designed with vacuum panels, plus higher heat resistance from the preform. If your line is hot-fill, flag it in the RFQ — it changes the neck spec and the resin/process, not just the bottle.
Aseptic (cold sterile)
Product and package are sterilised separately then filled cold in a sterile zone — common for dairy, ESL and sensitive juices. Because the fill is cold, you can use standard PET and standard finishes (e.g. 32/15 for juice & dairy), but the closure and neck must hold a guaranteed hermetic, tamper-evident seal. Aseptic is about sterility and seal integrity, not heat resistance.
Quick decision guide
- Cold fill → standard PET; 29/25 (water), PCO 1881 (CSD), 32/15 / 38 mm (juice & dairy).
- Hot fill → heat-set neck + higher-temperature-resistant preform; confirm with engineering.
- Aseptic → standard PET; prioritise closure seal integrity and tamper evidence.
How to specify it right
Tell us the filling technology up front in the Smart RFQ Builder, filter candidate SKUs by application and neck in the Product Finder, and confirm thread/seal compatibility in the Preform → Bottle Advisor. Unsure of a term? See the glossary. Delta El Nile for Industry’s team will confirm the neck and resin against your line before quoting.