If there’s one rule that ought to hold firm in the home-brewing hobby, it’s this: if the big-name breweries can do it in their factories, then you can do it at home. It’s that simple.
In theory, anyway; in practice, as with so many things in life, it’s not always that simple. Which brings us to twist-off caps and bottles.
A twist-off cap is exactly what it sounds like: it’s a cap, usually on beer, that can be twisted off by hand – no bottle opener required. They are distinct from screw caps in that they cannot be put back in place once opened (but are twisted off in the same way) and pry-off caps, which look identical to twist-offs but require, well, prying off.
Twist-offs and pry-offs are both typically “crown” caps – the distinct crown-shaped metal caps you see on Budweiser, San Miguel or pretty much any commercial beer bottle. The difference lies in how they’re opened, and the kind of bottle they’re put on.
Traditional pry-off bottles are intended to be re-usable, and so they’re made of sturdier, higher-quality glass. This makes is easier to reuse – but even these have a breaking point, as the glass will fatigue with each successive use.
Twist-off bottles are single-use, which means they’re lighter, more fragile, and not intended to be re-used (as you might have guessed from their being single-use). They’re also more expensive (single-use, remember?).
All this is well and good, but it’s nothing more than a mildly interesting diversion if you’re a brewing neophyte new to the whole art of bottling and capping. It’s therefore necessary to examine an important question:
How do you cap glass bottles?
Setting aside everything else regarding the home-brewing process, capping a glass bottle is a pretty straightforward affair. You simply need a supply of crown metal caps (easily purchased online, but be warned – cheaper ones are flimsier and less forgiving of capping mistakes) and one of two capping machines:
The hand-held ‘wing’ capper
Operated entirely by hand, wing cappers are relatively easy to use, if a bit hard on the arms. Be careful not to apply too much pressure, or they can be difficult to retract (or can even, if re-using glass, result in broken bottle necks).
The bench capper
You’ll be paying about twice as much for a bench capper as a wing capper, but that increase in price is accompanied by a commensurate ease of use. There’s little room for error with a bench capper, as the bottle is held firmly in place and usually sports a magnetised head to make sure the crown cap isn’t misaligned.
Now that we’ve got an idea of how glass beer bottles are capped in the first place, it’s necessary to ask ourselves the following question…
Why do some beer bottles have twist-off caps?
Simply put: convenience. How often have you roamed the kitchen, cursing the gods for your bottle opener’s ability to grow legs and wander off? How many times have you busted a bottle lip opening it on the side of a table, or risked your dentist’s good work popping it off with your teeth?
Twist-off caps eliminate the need for all of that (with the negligible caveat of making you feel a bit less manly).
As we’ve mentioned, twist-off bottles tend to use weaker glass and are intended for one use only. On a macro scale that’s not quite as good for the environment; on a micro scale (i.e. you) it means you have to be more careful about capping a twist-off bottle.
Which brings us nicely back to the reason we’re all here:
So can you use cap a twist-off bottle?
You certainly can – but as noted, it’s important to remember that the glass used for a twist-off bottle is weaker. You’ve probably noticed this yourself – if you’ve drunk a commercial bottled beer recently like Bud, you’ll find that the bottle is lighter and somehow less substantial than that of a beer with a pry-off cap. This means that you need to be more careful when capping it.
As we’ve covered, a bench capper is far superior when it comes to capping your bottles, and this goes double for twist-off bottles, innately predisposed as they are to breaking more easily. Because of that fragile neck, capping by hand can very quickly lead to calamity, so don’t bother – stick to a bench capper.
It’s important to note that it doesn’t matter what type of crown cap you use – you can use a pry-off just as easily as a twist-off cap. Note that our following advice still applies – if you go cheap, you increase your chances of a mishap, so whether pry-off or twist-off, don’t skimp on the cost!
Finally, it’s worth mentioning on this point that if you’re buying twist-off bottles as new, they’re on the pricey side. Because they’re designed for one use only, they’re more expensive, generally, than multi-use returnable bottles.
But what about if you’re using twist-off caps along with your pricier twist-off bottles? Twist-off crowns don’t generally become deformed after use like their pry-off cousins, after all, so surely it follows…
Can you re-use twist-off caps?
Generally speaking: no. Although twist-off caps are subject to far less deformation than pry-offs, the metal used is softer (this is why it doesn’t tear your hands up when you twist it off) and there is still some deformation that occurs when they’re removed.
This means that, even if you think you’ve done a good job of re-using a twist-off cap, you may be sorely disappointed when you come back to a flat beer in a week’s time. Given the ubiquity of affordable bottle caps, we’d recommend skipping this particular cost-cutting option.
And so to recap (sorry): it’s perfectly possible to cap a twist-off bottle – but if you’re going to do this, it’s probably best to re-use incidental empties rather than buying them for this purpose, and it’s probably best to limit the number of times you do this. That glass fatigue we mentioned earlier? This will affect twist-off bottles much faster than pry-offs.
Capping twist-off bottles, then, is a great way to get a bit more use out of those you’ve got hanging around – but you’re not going to build an empire out of it. If you want a bit more sustainability out of your bottling, stick to pry-offs.