In whisky packaging, sealing and tamper-proof design are crucial. The 31.5mm aluminum cap provides a sturdy barrier using lightweight aluminum and a tamper-evident structure. Aluminum ROPP caps are widely compatible with various whisky bottles, ensuring product freshness, safety, and brand integrity.
Why Choose 31.5mm?
The 31.5mm (approximately 1.24 inches) diameter is a standard size for whisky bottle openings, offering several advantages:
Universality & Compatibility: Ensures perfect fit with most whisky bottles globally, simplifying procurement and enabling automated bottling lines.
Optimal Handling: Easy to grip and twist, making opening and resealing convenient.
Structural Strength: Sufficient to accommodate complex internal sealing structures while maintaining aluminum shell integrity during transport and daily use.
Common Size Options
| Size (Ø × Height) | Applicable Bottle | Features |
| 31.5 × 18 mm | Small bottles | Compact seal, cost-effective, ideal for sample or trial bottles |
| 31.5 × 24 mm | Medium bottles | 350-500ml whisky |
| 31.5 × 44 mm | Standard bottles | 500-700ml whisky |
| 31.5 × 60 mm | Premium gift bottles | High-end whisky & commemorative editions |
Advantages of 31.5mm Aluminum ROPP Caps for Whisky Bottles
Excellent Sealing:
Aluminum caps tightly integrate with internal liners, creating a strong barrier to prevent oxygen ingress and protect whisky’s complex flavors.Lightweight Yet Durable:
Aluminum is light, reducing overall bottle weight, yet provides strong protection against impact or compression during logistics.Corrosion Resistance & Safety:
Aluminum resists alcohol corrosion and does not release harmful substances, ensuring the beverage’s purity and safety.Customizable Appearance:
The metallic finish can be customized with colors, logos, and print effects to meet high-end whisky branding needs.High Tamper-Evidence:
The cap bottom often has a perforated or weak-ring design. On first opening, the tamper-evident ring breaks, remaining on the bottle neck to provide visible proof of tampering, preventing counterfeiting or refilling.Recyclable:
Aluminum is 100% recyclable, supporting sustainable packaging trends.
Technical Specifications of Whisky Aluminum Caps
| Name | 31.5mm Aluminum ROPP Cap |
| Diameter | 31.5 mm |
| Height | 18 / 24 / 44 / 60 mm (customizable) |
| Material | 8011 / 3105 / 3003 aluminum |
| Thickness | 0.20-0.28 mm |
| Color | Gold, Silver, Black, or customized |
| Printing | Silk screen, hot-stamping (gold/silver), UV full-color, embossing |
| Liner | EPE, Saranex, composite, custom logo liner |
| Packaging | Bulk, carton, pallet, or custom packaging |
| Samples | Available |
| MOQ | 80,000 pcs |
FAQ
Q1: Which whisky bottles are compatible with 31.5mm aluminum caps?
A1: Designed for bottles with a 31.5mm neck diameter. Depending on bottle height and volume, different cap heights (18mm, 24mm, 44mm, 60mm) are available for sample bottles, standard medium bottles, and premium gift bottles.
Q2: Can aluminum caps completely prevent whisky oxidation?
A2: They greatly slow oxidation but cannot stop it completely. Trace oxygen may still enter, especially after opening when headspace increases. Compared with loose corks, aluminum caps provide superior protection. Retightening after each use maximizes flavor preservation.
Q3: Can the cap color, printing, and logo be customized?
A3: Yes. Custom options include silk screen printing, UV printing, hot-stamping (gold/silver), embossing, and personalized logos.
Q4: Are aluminum caps food-safe?
A4: Yes. Food-grade inner coatings (BPA-free) comply with FDA, LFGB, and other international food safety standards. Safe for contact with alcohol and beverages, non-toxic and odorless.
