Which bottle fits which pump? The practical Altglas guide
You have saved a beautiful gin, juice or lemonade bottle and want to turn it into a soap dispenser? Great idea—but before ordering a pump, there is one important question: will it actually fit the bottle?
Bottle necks often look similar at first glance. In practice, just a few millimetres, the closure type and the shape of the opening determine whether a pump sits securely. This guide walks you through the process step by step. It helps prevent unnecessary orders and gets your favourite bottle back into everyday use sooner.
Step 1: Does the bottle have a screw thread or a cork closure?
Start by looking closely at the bottle neck. A screw-top bottle has clearly visible ridges around the outside, and its original cap twists onto them. A cork bottle normally has a smooth outer neck because the closure previously sat inside the opening.
This distinction matters because a threaded pump is attached differently from a version that uses a sealing ring:
- Screw-top bottle: The pump screws directly onto a compatible external thread.
- Cork bottle or bottle without a compatible thread: A silicone sealing ring sits inside the opening and holds the pump securely.
Pro tip: Keep the original cap for now. It can help with the easiest compatibility check.
Step 2: The quick cap test for a 28 mm thread
Our pumps are based on a 28-400 thread. The 28 mm version suits many bottles with an external thread diameter of approximately 26 to 28 millimetres. Examples include certain sizes from Lemonaid, ChariTea, Jack, Bombay and other bottles. The exact bottle size still matters because one brand can use several different closures.
The simplest check uses the cap from a bottle that has already been confirmed as compatible. Carefully screw that cap onto the bottle you want to reuse. If it goes on straight, turns without force and closes fully, that is a very good indication that a 28 mm pump will also fit.
Never force it. If the cap catches for only half a turn, sits at an angle or is difficult to move, the threads are probably incompatible. A pump should sit securely without putting the glass or plastic mechanism under strain.
Step 3: Measure bottles without a compatible thread
For cork bottles and bottles with an unsuitable external thread, the important measurement is the inside diameter of the opening. Our sealing-ring set covers openings from 18 to 23 millimetres with three sizes: 18–20 mm, 20–22 mm and 21–23 mm. The ranges overlap deliberately so you can choose the ring that fits your particular bottle securely.
A caliper provides the most accurate measurement. Place its internal jaws against the narrowest inside edges of the opening and read the result. Measure in two directions if possible, as handmade or unusually shaped bottles can be slightly irregular. A ruler is useful for a rough estimate, but a caliper is more reliable when only a few millimetres make the difference.
Find the right version in five minutes
- Clean the bottle: Remove the closure, rinse the neck and dry it. Residue can affect both the measurement and the fit.
- Identify the closure: Visible external thread? Begin with the cap test. Smooth cork neck? Measure the inside.
- Test the cap or measure the opening: Never use force. For sealing rings, measure the inside diameter—not the widest part of the outer neck.
- Choose the version: Use the 28 mm pump for a compatible thread. For an inside opening between 18 and 23 mm, consider the sealing-ring set.
- Check the fit before filling: Assemble the pump on the empty bottle first. It should stand straight and should not move sideways when pressed.
Which sealing ring should you use?
Start with the ring whose size range matches your measurement. It should be possible to insert it while remaining firm enough to stop the pump wobbling during use. If fitting it requires excessive pressure, try the next smaller ring. If it slips out easily, move up to the larger size.
The sealing rings can also be used with threaded bottles when the inside opening is suitable. Part of the external bottle thread will remain visible, however. If you prefer the cleanest possible appearance, a directly compatible screw thread is usually the more elegant solution.
Common selection mistakes
Choosing by brand instead of bottle size
A 50 cl bottle can have a different closure from the 70 cl version made by the same brand. Do not rely on the label alone—always inspect the actual bottle neck.
Measuring the outside when the inside matters
For a sealing ring, the clear internal opening is what counts. The thick outer glass rim tells you very little about which ring will fit inside.
Tightening a pump that sits at an angle
If the thread does not engage cleanly, turning harder will not make it compatible. Remove the pump and try again. If it continues to sit at an angle, choose another bottle or check whether the sealing-ring version is suitable.
Leaving the tube too long
Our pumps have a tube approximately 20 centimetres long so they can also work with taller bottles. For a smaller bottle, trim it with clean household scissors. Measure the bottle first and leave the end just above the bottom so it can draw up the soap without bending sharply.
Budapest, Zagreb or Roma: Which look suits your bottle?
Once you know the technical version, you can focus on the enjoyable part: style. The Budapest pump has a slightly taller, clean shape that looks particularly elegant. Zagreb is more compact and comes in a wide selection of finishes, from stainless-steel looks to dark and warm metallic tones. The Roma pump is a minimalist alternative for selected 28 mm screw-top bottles.
Think about where your new dispenser will stand. Brushed metal feels understated and practical, dark pumps create a strong contrast with clear glass, and warm metallic colours work beautifully with amber or green bottles. Several models might be equally suitable technically, so the visual choice is entirely yours.
Before first use: clean, trim and test
Rinse the bottle thoroughly and remove all traces of its previous contents. Wash the pump by hand with mild washing-up liquid; it should not go in the dishwasher. Only shorten the tube after choosing the final bottle. Then add a little water and test the mechanism. This confirms that everything sits securely before you fill the bottle with soap or washing-up liquid.
Label the finished dispenser clearly, particularly if the original drinks bottle is still recognisable. That turns beautiful waste glass into a safe, practical everyday object.
Conclusion: Check first, then upcycle
Finding the right pump does not have to be guesswork. Identify the closure, use the cap test for screw-top bottles and measure the inside diameter of cork bottles. A few minutes of preparation will tell you whether you need a 28 mm version or the 18–23 mm sealing-ring set.
All that remains is your favourite bottle—and a piece of packaging becomes a distinctive soap dispenser that you will enjoy using every day. Which bottle is already waiting for its second life?