Beer bottle caps come in various colors and shapes and it’s not unusual for homebrewers to pass hundreds of caps through their hands every month when they brew a lot.
Something used in such quantities must be cheap and they are, however, reusing them would still save you a lot in the long term, so are the beer bottle caps reusable?
Beer bottle caps are reusable as long as they are not damaged when the bottle is opened, if they are damaged they can cause seal issues, let the Co2 escape, and let the oxygen enter the bottle which can ruin homebrew. Thus, it’s not recommended to reuse bottle caps.
Bottle caps aren’t a complicated matter, but knowing a few facts about them just as that there’s an alternative to what you might be using right now is always helpful.
Should you reuse bottle caps?
So, although not recommended, bottle caps are reusable and that’s great because if it’s your last resort as you must bottle and there are no new caps, you can reuse the old bottle caps. However, should this be a practice that will save money even if you have access to new bottle caps?
I think it’s not worth reusing bottle caps for your homebrew as bottle caps are extremely cheap and they can be found at 0.03$ per piece, and the risk that comes with reusing old bottle caps is not something I’d be willing to take.
You’d need to manually check each bottle cap and look for imperfections and then after bottling test each bottle to see if the seal is firm. This means more risk and work and we already have lots of work on a bottling day.
So, if you ask me I’d rather play the game with a beer bottle opener launcher (link to Amazon) and compete against my partners in brew than save the caps to reuse them.
Use alternative reusable caps
If you want to reuse the caps, don’t use the common metal caps (see the caps on Amazon) which are not meant to be reused, but rather use the caps which are specially made for this purpose.
Flip top caps
If you want to save money on caps (which is perfectly reasonable) you should look into Flip top bottle caps you can get on Amazon. These bottle caps are made for reusing, so it’s not possible to damage them and you don’t even need a capper machine.
These bottles are more expensive, but after a second batch, the investment will start to make sense as you won’t need new bottles or caps. The only issue is that you must be careful when you lend the homebrew to friends and family as you will want these bottles to be returned at all costs (people are sometimes forgetful just as they are when they borrow a book).
Reusable rubber caps
The other option you have are rubber reusable caps (found on Amazon) as they are easy to clean and put on. However, I’d not recommend these caps for long-term storage but rather when you need to save a beer for a short time such as overnight as they’ll leak CO2 and are easy to knock off if you are not careful.
These caps are a better solution for wine, mead, or other flat brew leftovers and are not ideal for beer, but are still a perfect solution when you can’t drink a beer in one sitting.
How do you put a beer cap back on?
Let’s say that you insist on reusing common metal bottle caps, this is what you should have in mind to put it back on a beer bottle.
Before you put a beer cap back on check whether the metal sides are bent if they are it may cause a leak. However, the only truly sensitive part of a cap that must not be damaged is the inner plastic part as it’s made to create the initial seal with the bottle. So, even if the metal corners are slightly banded it may not be a problem as long as the plastic inner area fits right back on.
Now, there’s a big difference between reusing beer caps for homebrewing purposes on a bottle day when you need to bottle the entire batch and when you open a beer and want to save the rest for later.
In the latter case, even a non-perfect cap will be of use if you are going to drink the beer within the next 24 to 48 hours, but storing homebrew for weeks in such a condition won’t be a smart idea.
If you are planning to bottle with old caps, check them for imperfections, clean them, apply sanitation solution, and bottle with the capping machine like the last time.
You can check for leaks by turning a bottle upside down and observing whether the sides of a cap get wet, but this way you’ll also introduce extra oxygen in a beer which is not ideal (unless you have a proper bottling technique).
How do you clean and sanitize beer bottle caps?
Clean
Cleaning means removing any visible stain or dirt on the cap as prior to sanitation it’s important that all large particles are removed. I used to make mistakes when I thought the sanitizing solution would get rid of all visible nasties, but it would only lead to infection in some bottles. When reusing bottles and caps, there will always be some sediment stains that must be removed otherwise, the germs can remain in there. To clean caps you can simply use hot water and some detergent and if necessary a brush or a piece of cloth you remove the hardened stains.
Dry
Drying is important for storing as a non-dried bottle cap can quickly rust which can become unpleasant. I always make mistakes and throw a bunch of caps in the bucket full of sanitizing solutions as I am too lazy to sanitize one by one.
Sanitize
Sanitizer is a must at all times and can’t be skipped. Simply throw a bunch of previously cleaned caps into the sanitizer/water mixture and use them when you need them.
Can you still use rusted caps?
Rusted caps may seem unusable at first, but they are most often perfectly fine and usable as the only part that will corrode is metal and not the plastics. The plastic inner part is the only part of a cap that ever gets in contact with the liquid if you rotate the bottle, while the metal sides are used to stabilize the cap around the top of the bottle throat. I have written more about rusted caps in a dedicated article, so if you are still worried check it out.