Match a closure to the bottle neck specification before choosing it by color or appearance. A stopper must fit the relevant internal dimensions, while a screw cap must match the specified finish and sealing arrangement. Ask for bottle and closure drawings, then test the assembled package. Similar-looking necks and caps are not evidence that two components will seal correctly.
Ask for the Finish, Not Only the Mouth Width
A bottle opening measurement is only part of closure selection. The supplier should identify the neck finish and provide the dimensions needed by the closure manufacturer. For threaded finishes, thread geometry and finish height matter as well as the diameter.
Berlin Packaging explains that neck finish dimensions describe different parts of the interface, including the internal opening and external thread. Its neck finish guide is useful background, but the approved bottle and cap drawings remain the references for a specific order.
Treat a Stopper as an Assembly
For a cork-style stopper, specify the sealing component separately from the decorative top. Discuss the stopper dimensions, material, insertion requirements and the neck dimensions it must match. A wooden-looking top does not establish the composition or behavior of the sealing component.
Ask how the sample will be tested using the intended bottle and liquid. Review insertion, removal and the appearance of the assembled package. If the brand also wants a capsule or tamper-evident element, include that component in sampling rather than adding it after the closure has been approved.
Define the Checks for a Screw Cap
For a threaded closure, ask which cap and liner or sealing system the supplier proposes for the specific finish. The filling partner should confirm the application equipment and the acceptance checks for the assembled package. Do not transfer application settings from an unrelated bottle simply because the cap looks similar.
The test plan should consider the filled product, closure installation, handling and expected storage conditions. Record the results and identify the exact bottle and cap revisions tested. If either component changes, ask whether the previous approval still covers the new combination.
Keep the Approved Pair Together
Review a 500ml vodka bottle with a cork reference alongside its current drawing and the proposed closure sample. You can also begin with 700ml spirits bottle designs if your brand needs a different format. A catalog reference identifies the sourcing discussion, not a confirmed seal test.
Ask RS Glass to quote the bottle and closure as clearly identified components. Keep an approved assembled sample and written specification with the project record. That reference is useful when purchasing repeat orders or comparing samples supplied by a different closure vendor.
Buyer Checklist
- Bottle neck drawing and revision
- Closure drawing, material and sealing component
- Application equipment and proposed checks
- Filled-package sample approval
- Capsule or tamper-evident component where required
- Change control for both bottle and closure
Frequently Asked Questions
Can a cork fit every bottle with the same opening diameter?
No assumption should be made from one measurement. Confirm the relevant internal dimensions and the proposed stopper specification through a matched sample.
Does a screw-cap diameter identify the whole finish?
Diameter is only part of the specification. Confirm the finish designation, thread geometry, height and sealing arrangement.
Should I order caps before the bottle is approved?
Coordinate the components together. A bottle and closure should be approved as a package before committing to bulk supply.
Related Buying Guides
500ml, 700ml or 750ml Spirits Bottles: How to Choose · Glass Bottle Sample Approval Before a Bulk Order
Discuss Your Bottle Project
Send RS Glass your bottle reference, capacity, quantity, closure, decoration requirements and destination. Request a project quotation or view the company and factory introduction.
