Bottle capping is one of those steps that looks simple, but it is easy to mess up if you rush it. I have capped plenty of bottles over the years, and once you understand the process, it becomes quick and repeatable.
Bottle capping is just one step in the process, along with fermentation, priming, and having the right home beer brewing equipment to get consistent results.
When people talk about bottle capping in beer brewing, they usually mean sealing beer bottles with crown caps using a bottle capper. This guide focuses on that exact process, from understanding the tools to avoiding common mistakes that lead to leaks or flat beer.
Table of Contents
What Is a Bottle Capper
A bottle capper is a tool used to crimp a metal crown cap onto a glass beer bottle. The cap seals against the lip of the bottle and locks in carbonation.
Most homebrewers use either:
- a handheld bottle capper, or
- a bench bottle capper
Both do the same job. The difference is how much control, speed, and consistency you want.
If you’re bottling beer at home, a bottle capper is essential. There’s no reliable way to seal crown caps by hand without one.
If you’re trying to decide which tool to use, I’ve put together a comparison of the best bottle capping tools for homebrewers.
How Does Bottle Capping Work
Bottle capping works by pressing and crimping the metal cap around the bottle lip. Inside the cap is a thin liner that creates an airtight seal when pressure is applied.
Here’s what’s happening during the process:
- The capper pushes the cap down evenly
- The metal edge folds under the bottle lip
- The liner compresses to seal the opening
If the pressure is uneven or the bottle isn’t seated correctly, the seal will not hold. That is when you get leaks or beer that goes flat over time.
How to Cap Beer Bottles Step by Step
This is the basic process I follow every time.
- Use the right bottles
Only use pry-off beer bottles made for crown caps. Twist-off bottles don’t seal reliably. - Sanitize bottles and caps
Clean bottles first, then sanitize them. I always sanitize the caps as well, even if they’re new. - Fill the bottles properly
Leave a small amount of headspace. Overfilled bottles make capping harder and messier. - Place the cap on the bottle
Set the crown cap straight on top of the bottle opening. - Seat the bottle in the capper
Make sure the bottle is centered and fully seated before applying pressure. - Apply firm, even pressure
Press straight down until the cap crimps fully. Don’t rock the capper. - Check the seal
The cap should be tight and even all the way around. If it spins easily, it’s not sealed.
Once you get a rhythm, the process goes fast.
Handheld vs Bench Bottle Cappers
Both types work, but they serve different needs.
Handheld bottle cappers
- cheaper
- portable
- fine for small batches
- require more attention to alignment
Bench bottle cappers
- more consistent
- faster for larger batches
- adjustable for bottle height
- take up more space
If you bottle occasionally, a handheld capper is usually enough. If you bottle often or want fewer failed caps, a bench capper is easier to use and more forgiving.
Common Bottle Capping Mistakes
Most capping problems come from a few repeated mistakes.
- Using twist-off bottles
These don’t seal well with crown caps. - Not centering the capper
Off-center pressure leads to leaks. - Reusing caps
Crown caps are single-use. Reusing them causes poor seals. - Rushing the process
Fast doesn’t mean sloppy. Take an extra second to align things. - Ignoring bad seals
If a cap doesn’t feel right, replace it immediately.
Catching these mistakes early saves a lot of frustration later.
Beer Capping Alternative
Some homebrewers prefer bottles that don’t require a capper at all. Grolsch beer bottles for home brewing use a swing-top closure that can be opened and resealed easily, making them popular for small batches and reuse without crown caps.
Eddie McVay
Eddie McVay is a home brewer with over a decade of hands-on experience making beer and wine at home. He started with a simple home brewing kit and learned through real batches, real mistakes, and constant experimentation. His articles focus on practical, beginner-friendly advice, clear explanations, and proven techniques that help home brewers get better results without overcomplicating the process. Read more about Eddie Mcvay here.