Packaging: The Last Frontier
I've judged both commercial and amateur brewing competitions for quite some time and one of the things that are common to both home brewers and commercial brewers is that packaging is hard. Like really, really hard. Packaging is so difficult that much of the advice given to people opening new breweries is to spend most of your time and money on the cold side of the brewery because so much can (and does) go wrong in that final leg of the process that an amazing sample can be a completely different beer in the hands of the consumer if you don't take steps to prevent it. In fact, you can get a whole degree just in packaging beer, completely separate from a brew master degree.
So, despite that daunting challenge, lets go over some of the types of packages, pros and cons and some tips and tricks that may hopefully keep your beer as close to the sample you pulled as possible.
There are four things that are going to wreck your beer post fermentation.
- non-oxidative degradation
Non-oxidative degradation can be solved via recipe choice, unless you're making a beer with a lot of wheat, a beer with a lot of brown or amber malts or the temperature differential between your heating element and your wort is too high. In other words, there's relatively little you can do about it, just don't crank the heat as soon as you start your boil.
Taints can be solved simply by using the right cleaning agent for the right purpose and rinsing well if it's not specifically a no rinse sanitiser.
Microbes are trickier as they can hide in a lot of places. Home brewers have the advantage here because they are able to take everything apart whereas commercial operations need to use much stronger chemicals and rely on hot water and pressure rather than seeing soil and manually scrubbing it away. They also have to keep strict production schedules whereas home brewers can just leave stuff to soak in a bucket. However, unless your stuff is made of stainless steel and silicone, you're going to need to keep an eye on it as microbes can and will develop biofilms that will survive whatever you're doing and eventually take over.
Lastly is oxygen. Oxygen is such a difficult issue to resolve that when we talk about packaging, we're largely talking about oxygen.
There are three ways of dealing with oxygen.
1. Don't allow the oxygen to touch the beer.
2. Remove everything in the beer that could possibly oxidise
3. Leave enough yeast in the final package to scavenge any oxygen that will inevitably be present.
The first method seems relatively simple, except that physics gets in the way, specifically the Venturi effect. The Venturi effect is essentially a reduction in fluid pressure at choke points in pipes. In order to balance this, the liquid flow speeds up to resume its original pressure. It does that because liquid doesn't compress very well. The increase in velocity results in a pulling effect and if there is any possible breach in the pipe or hose, it will suck air in. In a brewery or in a homebrew setup, those choke points tend to coincide with places where one pipe meets another or where a hose attaches to a fitting. This results in a pulling action on the seal which will, despite our best efforts, allow at least some oxygen in.
What this means is that every transfer, no matter how cautious, will result in some oxygen ingress. There is no such thing as an oxygenless transfer. We can keep dissolved oxygen below certain thresholds - current accepted standard is 0.3 ppb, but it will always occur. The obvious solution is to avoid transfers - which brings me to my first package, the brite tank. On the commercial side, the brite tank is usually where you store finished beer - filtered or unfiltered just before you package it. For most homebrewers, this would be the keg. Some breweries, such as Blind Enthusiasm, serve directly from the brite tanks, eliminating transfer oxidation issues, and at the homebrew level, you can serve directly from the keg. Of course, the cons of doing this are that it's not particularly portable. If you want to bring anything smaller than a keg to a party, you have to do another transfer.
I'm going to go off on a slight tangent here to talk about the difference between oxygen and oxidation, because it's super important to understanding why transfers are such an issue. Dissolved oxygen meters measure oxygen, as in O2. They do not measure free oxygen radicals, as in singular oxygen atoms. Oxygen is ridiculously reactive, which means that it almost instantly bonds with whatever it can. Once it is bound, it is no longer detected by a DO meter. This means that if your DO meter is telling you that your transfer is only letting in 0.3 ppb, that is what is currently happening on THIS transfer. That 0.3 ppb will react with whatever it can in your beer and the next time you transfer, your DO meter will pick up an ADDITIONAL 0.3 ppb. Oxygen ingress is cumulative. Oxidation is what happens after. Over time, oxygen attached to lipids, proteins and polyphenols will degrade and release free oxygen radicals. These are even more reactive and are what causes staling, aldehydes and any other number of weird flavours in your beer that weren't there before. This is also why judges at competitions may be tasting things that are completely different than what you tasted before you sent it off.
This leads me into the second method of reducing oxygen, which is removing everything that could possibly cause oxidation. This is out of the realm of possibility for the home brewer and even most craft brewers, but I want to touch on it briefly because it's how you get arguments like whether hot side aeration matters. So being brief and avoiding technical stuff, if you pass beer through special filtration processes that remove protein and polyphenols that will oxidise (not all of them will), you don't have to worry about oxidation.
Having said that, understanding that protein, polyphenols and lipids cause the release of free oxygen radicals over time, it stands to reason that you want to limit the amount of those in your finished beer. This is why beers with a high amount of protein, such as wheat beers show their age after only a few weeks.
So leaving that unattainable method behind, why do wheat beers like German hefeweizens and most Belgian offerings seem to make it over here and stay relatively fresh? (though I would argue that they're noticeably different to even the most untrained taster after 3 months) The answer is the third method, which is yeast.
It has long been assumed as homebrew gospel that bottle conditioning is the inferior method of carbonating because homebrewing started back when people compared everything to light lagers or something equally as clear. If your idea of what beer is is a Coors light and you're presented with a hefeweizen, you'd think it was infected. In addition, outdated information about how long beer should sit on yeast and a corresponding quality increase of ingredients and equipment available to homebrewers along with beer guns led to leaving bottle conditioning by the wayside.
Consider, however, that the beers that don't require brilliant clarity, such as the aforementioned wheat beers, all use bottle conditioning - nor do they suffer from any of the supposed deleterious effects of leaving your beer on the yeast too long? I'll leave the beer world for a moment and ask you to consider champagne. The process to make champagne takes at least 5 years. It's a bottle conditioned product, which is then slowly tilted over those 5 years so that a solid yeast plug accumulates near the neck of the bottle, at which point is it opened, shot across the room and then corked before it makes too much of a mess. No-one has ever described a bottle of champagne as having any of the flavours characteristically associated with sitting too long on the lees. So where did those perceptions come from? Well, you'll get those flavours if you leave your beer sitting on the yeast at primary fermentation temperatures for months. At conditioning temperatures, you can leave it there for quite some time.
With that out of the way, let's talk about how commercial brewers that bottle condition do it and how it helps in reducing oxygen related aging, and then how you can possibly adapt those lessons to your own practices. Hefeweizen brewers will generally use speise or krausen to prime their bottles. This is either fresh wort or fresh yeast at the height of fermentation. What this gives you is sufficient nutrients to continue growth or yeast at the height of it's growth phase to finish off the beer. Both of these methods will use up the most oxygen. Belgian brewers will pitch fresh yeast, often a different strain for more complex flavours, but the end result is the same. Fresher is better and nutrients are key. Oxygen without nutrients = problems.
The package you choose is going to determine the amount of oxygen related aging. PET bottles are not suitable as they are oxygen permeable over time. Glass bottles are a solid choice, along with oxygen scavenging caps and cans are great for all sorts of reasons which is why most of the brewing industry has moved to them, but at the homebrewing level, canning equipment is expensive and can be finicky. Purging with CO2 is easier with bottles, but can still be done with cans and like other areas of the brewing world, canning is becoming more accessible to homebrewers and will likely continue to develop as time goes on. The most important variable however, is headspace.
Someone did a calculation of the amount of oxygen left in the headspace if you do a fill with a bottling wand, retract it and then cap it. It came out to almost 4 mL of oxygen, which, if you did nothing else, would eventually diffuse into the beer and give you about 7 ppm of oxygen, which is basically the same as leaving your beer uncapped in a sterile room. Yeast will scavenge some of that, but obviously not all as 8 ppm is basically what you get when you aerate your beer by splashing. This means that even with the protection of yeast, you need to either minimise headspace or purge headspace. Now this headspace oxygen is going to diffuse more slowly in a bottle than in a can because the surface area of the liquid is smaller in a bottle and so a lot of smaller operations were getting around this by basically overfilling, leading to an instant burst of foam when you opened a can.
I would pick two best practices that work at the homebrew level. If possible, priming with speise and/or krausen, followed by purging any headspace. I do this with most kegs, including lagers without a noticeable difference in clarity - at least not one that the naked eye is going to pick up. If I'm filling from the keg, I'll mirror what modern canning operations are doing which is to dispense a small amount of sacrificial beer and then flash it with CO2. This is going to fill up the can with foam, but unlike Star San, these bubbles will be full of CO2 instead of air. Filling underneath that seems to keep your DO levels below the 0.3ppb threshold and is relatively easy to do with a beer gun. Obviously capping as soon as possible keeps things as oxygen free as possible.
I've been playing with this for awhile and I can safely relate the following observations:
- The more alcohol in your beer, the longer it's going to last
- The more brown malt you use, the shorter the shelf life
- The more wheat in the beer, the shorter the shelf life, though alcohol seems to go a long way to counteract that
- Old crystal malt has a distinct old crystal malt flavour. If your beer has crystal in it, you've got 2 months tops, unless its a barleywine, in which case, it's supposed to taste like that.
And as always, it's just beer. If you don't like it anymore, you can always dump it and brew more.