This five-part series focuses on providing brewers with structures and tips to navigate the fundamental areas where the collective effect of these small decisions has the greatest impact on beer quality.
Part 5 – Packing It Up
As fermentation draws to a close, the brewing process enters the final stages, and the brewer’s work is almost done. A great tasting beer at the end of fermentation is a fine accomplishment.
From a process point of view, the majority of decision making is complete, with the beer now requiring a little “alone” time to slowly refine and mature before the relatively straightforward last few processing steps.
In this last piece of the series, we follow the brew from cold conditioning through to that glorious final moment of enjoyment!
Time to Chill
With primary fermentation complete, focus turns to maturation.
A simple definition of maturation is the period of time that the beer is held in tank at a cool temperature, prior to the removal of yeast.
Several processes are occurring concurrently during this extended storage, with clarification and the refinement of flavour being of most importance. Understanding these processes allows you to shorten maturation time without compromising on quality, thus realising a greater utilisation efficiency of your available capacity.
The primary goal of maturation is the provision of time for the yeast to metabolise, and thus reduce, the impact of certain off-flavours that may be remaining in the beer at the end of primary fermentation. Acetaldehyde, sulphur compounds and diacetyl are the major compounds of concern.
In practice, most of the pathways active during maturation were also occurring during fermentation. The reduced temperatures result in much of the yeast going dormant; however, sufficient yeast activity still occurs to influence beer flavour for the better.
Without sugar to ferment, the remaining active yeast instead hyper focuses its attention on processing the remaining by-products, albeit at a slower rate. This reduction in the metabolic rate is the main reason maturation is generally the longest part of the entire brew cycle.
In modern craft brewing, maturation times are trending down without sacrificing beer quality. This is being driven by several factors:
- Beer is entering maturation in a ‘cleaner’ state as brewers opt for extended VDK rests at the end of fermentation. The warm rest also gives yeast a head start on metabolising other post-ferment compounds.
- Consumer acceptance of residual yeast in the final beer means that these maturation pathways remain active whilst the beer is packaged and waiting to be consumed. You can rely on this time to complete the maturation process, thus freeing up tank space earlier.
- The trend towards higher hopping rates and bolder flavours has a masking effect on fermentation off flavours, resulting in brewers being prepared to release tanks before these compounds are fully reduced.
Keep in mind:
– Whilst common practice, cold storage need not be conducted at 0 degrees. Although the colder temperatures promote better clarification (we’ll look at that shortly), slightly warmer temperatures will see faster flavour improvements. This can also be a great energy saving, well worth consideration if beer clarity isn’t of high concern.
– Utilising a secondary fermentation can ensure there is sufficient healthy yeast for the maturation time.
The other prominent process occurring throughout cold storage is clarification. Extended storage at low temperatures allows the yeast to flocculate and settle to the bottom of the tank. It also promotes the formation of chill haze complexes formed when proteins and polyphenols interact, which can then be removed by filtration.
Time required for clarification has also considerably reduced in the last decade for multiple reasons:
- Centrifuge technology has become viable in mid-sized craft breweries, allowing yeast to be quickly spun out of solution as soon as it has finished the task of flavour refinement.
- Acceptance of the use of process aids to aid flocculation of yeast and precipitation of proteins. The use of these is no longer seen as a compromise to craft credentials.
- Acceptance of residual yeast in beers (not just hazys!) results in much less time waiting for the stubborn non-flocculating yeast to fall out of solution.
Keep in mind:
– Eliminating chill haze is achieved by targeting just one side of the protein / polyphenol complex. Utilising multiple process aids to target both simultaneously can provide additional security and yield better results.
– Removal of proteins and polyphenols is not only significant for improved visual appeal. It is important to remain mindful of the flavour impact they have and do not completely disregard controlling their levels, even in cases when your beer is destined to be hazy regardless.
– Periodic removal of yeast that has settled is still important to prevent autolysis, although not as frequently as during fermentation. Twice per week is generally sufficient.
There are many options for filtration available each providing unique challenges in respect to maintaining beer quality. Whatever the method chosen, minimising oxygen pickup must be given a high priority.
Keep in mind:
– When targeting brilliantly bright beer, filtration should be conducted as cold as possible, to ensure that any chill haze complexes are formed and trapped by the chosen filter media.
– Using diatomaceous earth is a relatively cheap way to remove almost all yeast. Care must be taken to ensure adequate training and protection of staff given its carcinogenic classification.
Carbonation of beer is a relatively simple step that has significant impact on beer quality. Carbonation affects how the beer pours, looks, smells and tastes so it is essential to hit your target and keep it consistent from batch to batch.
Keep in mind:
– Invest in a quality gehaltemeter. Top pressure and equilibrium charts can be used as a guide, but nothing beats actually knowing the exact level of carbon dioxide in your beer.
– Account for losses when bottling or canning so that the beer is right for the end consumer, not the bright beer tank.
– Be sure to put top pressure on your tank before injecting carbon dioxide through a sintered stone. Care must be taken to minimise any creation of foam in the bright beer tank as these foam-positive proteins need to be saved to make foam in the glass.
Packaging: the final hurdle in ensuring your beer leaves the brewery in top condition. With equipment options to suit every budget, every brewer is faced with different challenges to maintain beer quality. The one we all have in common, and by far the biggest concern, is managing the dissolved oxygen pickup.
Success in this task comes down to one critical component: a dissolved oxygen meter. We can’t control what we can’t see, so investment in an accurate and reliable meter is the only way to ensure packaging processes can be understood and carefully managed to limit oxygen ingress.
Keep in mind:
For Cans and Bottles:
– If you don’t have a DO meter, use a forced age test to help determine if your packaged beer is within specification before releasing the batch.
– Avoid letting your first one or two cycles through the filler out to the consumer. Packaged stock on the start or end of the run (or significant stoppages) is likely to have higher dissolved oxygen and variations in carbonation.
– Keep a beer library of every batch by retaining a 4 or 6 pack in a cool dark place. It is incredibly valuable to be able to directly assess the same batch if you have any quality issues or complaints with stock in trade. It is also helpful for sensory training and your own continual improvement.
– Ensure you (or your keg washer) restricts flow up the spear during cleaning so that the cleaning solution, or rinse water, is able to run back down the outside of the spear itself.
– Don’t rush the filling process. Utilise back pressure and find a speed that prevents the production of foam. Just like when carbonating, beer will only produce a good foam layer once so it is best to make sure that is in the glass, not the keg.
– Auto shut off float valves are an excellent way to reduce waste when multitasking keg filling amongst other brewing tasks.
Out of Your Hands.
The process is finally complete. The beer has been designed, brewed, fermented, matured, packaged and is tasting fantastic. There is just one thing left to do – enjoy it, right?
Whilst technically true, it is easier said than done.
It is at this point that control is often relinquished to distribution chains, retail partners and consumers themselves. This might just be one of the hardest parts of brewing to get right, as the few simple things that need to be done, need to be done by someone else!
Keep in mind:
– Keep it cold. One day of warm storage has the same aging affect as seven days cold storage. Looking at this ratio for the timeframes when most beer reaches the consumer shows just how quickly this makes a difference.
*Two days stored warm is the same quality as two weeks cold.
*Two weeks stored warm is the same quality as three months stored cold.
*Two months stored warm (still a reasonable supply chain time) results in beer the same quality as beer stored cold for almost two years!
– Clean the lines. There really is nothing worse than seeing great beer ruined by a dirty beer line. Whilst it might be obvious to you what needs to happen, there are many bar owners that are either unaware, or perceive the cost of line cleaning as the bigger issue. Offer training to your wholesale customers, or support to ensure regular cleaning is occurring.
Time for a Beer
One last thing to do – sit back and enjoy a glass of your hard work. Whilst of course you deserve it, it’s always important to drink a sample from every batch and jot down a couple of notes as to how the final beer presents. It is these notes and reflection that allow us to continuously improve on what we do.
Talk to friends and colleagues, request and accept honest feedback, and don’t forget to pat yourself on the back from time to time. Beer isn’t always perfect, but it’s always the perfect thing to enjoy with friends.
I hope you have picked up a tip or two throughout the series. Every small improvement we make in our brewing leads to a more rewarding experience and ultimately, better beer for all!
You can find the first 3 articles in this series here:
Brewing Brilliant Beer, Pt 1: Getting Your Recipe Right
Brewing Brilliant Beer, Pt 2: Brewers Make Wort
Brewing Brilliant Beer, Pt 3: Yeast Makes Beer
Brewing Brilliant Beer, Pt 4: Fermentation & Flavour
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