Brewery Vessels Guide Part 2 – Cellar Tanks

Brewery Vessels Guide – Cellar Tanks

This brewery cellar tanks guide, is the second article in our brewhouse vessel series. If you missed the first part on brewery fermentation vessels, please click the link to check it out.

In this post we look at the other tanks we typically see in a brewery cellar. The vessels types a brewery houses, depends on the styles of beers being brewed.

As mentioned in the FV article, most modern breweries have DPV (dual purpose vessels) also known as unitanks. DPV’s are used for both fermenting and maturing beer.

Cellar Tanks

However, in traditional lager brewing, there are tanks designed for maturing lagers specifically, after primary fermentation. It’s with these tanks, where I’d like to start.

Brewery Cellar Tanks Guide – Horizontal Tanks

I’ve a soft spot for horizontal maturation tanks. Why? Well, my first brewing gig back in the late 90’s was as an assistant brewer, in a dedicated lager micro-brewery. It was the only craft lager brewery in the UK at the time.

Side note: We actually had another type of tank, typical to lager brewing. It was a “starter tank”. The cooled wort went to this tank after the brew kettle, and the yeast would be pitched.

The wort was left in this “starter tank” for around 24 hours, then transferred into a clean FV. The principle behind this style of tank; was to leave trub and sediment behind. Leading to a cleaner finished beer.

These starter tanks aren’t really used in modern breweries anymore. Instead, commercial brewers just dump the sediment from a bottom of the FV, the day after the yeast has been pitched.

…now back to the horizontal tanks.

Horizontal tanks are just that, horizontal. In most breweries they stack these tanks, to optimize the use of available space in the brewery.

Cellar Tanks

Lager comes from the German word “to store”. After the fermentation is completed and chilled to between 0 and 4°C (32 – 40°F). The beer is transferred to these horizontal tanks, where the beer is cold stored for around a month.

During maturation, haze-inducing proteins and polyphenols coagulate and fall to the bottom of the tank. Furthermore, in this time, the beer mellows, becoming more delicate as well.

The Advantages of Using Horizontal Tanks – Brewery Cellar Tanks Guide

Horizontal tanks are making a comeback; because lager is gaining popularity in the craft brewing community. Why? Well…Covid-19 led to this development which I actually predicted in late 2020.

As breweries saw a drop in sales during the original lockdown, it led to freer tank space. This allowed breweries to brew lagers, as they had time to store and mature the beer.

Then these lagers were drunk by craft drinkers, who liked them and thus demand for craft lager increased. I’m seeing more of my clients asking about horizontal lager tanks. If you’re planning to make a lot of lager, these tanks are ideal.

You see, once the beer has been moved to a horizontal tank, it frees up an FV to brew another beer. Instead of A DPV being taken up by a beer needing 30 days of maturation.

Other Advantages of Horizontal Tanks 

As a brewing consultant, there are some other legitimate reasons why I recommend these tanks if you brew a lot of lager. These are:

  1. Moving the beer from an upright FV to a horizontal tank, reduces the hydrostatic pressure exerted on the yeast. This leads to less stress on the yeast and potentially a cleaner beer. During the maturation phase things happen more slowly, with the yeast at the end of its cycle. If the yeast is less stressed; it’s “happier” to carry out its work, leading to a cleaner more refined finished beer.

Cellar Tanks

  1. These horizontal tanks are more “flat bottomed”, when compared to a cylindroconical FV’s. Meaning a larger surface area, for the maturing the beer comes into contact with the yeast. This greater contact area allows the yeast to work on the beer more easily. Which helps it clear up the brew and pull all the flavors together.
  1. With horizontal tanks, your essentially turning beer on its side. There’s less distance for the yeast, proteins plus other solids to travel and drop out suspension to the bottom of the tank. This helps clear beer more easily and quicker too.

Brite Beer Tanks (BBT’s)

Most beers if left long enough, will clear up naturally. However, most breweries can’t wait several months for a beer to clear itself. So, they use other methods to speed up the clearing process.

A few methods a brewer can use are:

Finings

Finings have been used for centuries to clear beer. In traditional British brewing; finings were made from the swim bladders of fish.

These finings agents have large molecules, which are positively charged. These positive molecules attach themselves to negatively charged contaminants, helping them precipitate out of the beer and settle to the bottom of the tank.

There are two common methods for fining:

One is to add them to a unitank, using a pump to mix the finings in properly. You then wait for the beer to clear, dumping the sediment from the bottom of the tank at regular intervals. Like every 24 to 48 hours.

The second option is to fine the beer inline, as it’s transferred to the BBT. You then wait for the beer to clear in the tank it’s been transferred too. Brewers like to use a BBT and clear beer, as it makes packaging easier.

Clearing Beer – Option Two Filtering

There are several types of filters a brewer can use; including a DE (diatomaceous earth), lenticular, bag and sheet filter. When using a filter, you’re transferring out of a uni or horizontal tanks via a filter (which clears the beer) to a BBT.

Brewery Cellar Tanks

Beer cleared Using a Sheet Filter

Centrifuge – Clearing Beer Option Three

The centrifuge uses “centrifugal forces”, to increase the density of heavier yeast and sediment in the beer. The radial forces push these heavier particulates towards the side of the centrifugal chamber.

In the meantime, the lighter water and alcohol stay closer to the central axis of the chamber. The yeast, trub and sediment is then dumped from the centrifuge with the clear beer being sent on the BBT.

BBT Roundup

Once you’ve clear beer in your BBT or Unitanks. It needs to be analyzed, before it can be packaged. The main checks are typically; DO (dissolved oxygen), CO2 volumes, turbidity and sensory.

The checks are to ensure the beer is within predetermined parameters. So, you customers get the beer they are expecting to drink. Plus, it also ensures the beer is shelf stable too.

Brewery Cellar Tanks

Beer shouldn’t stay too long in BBT. It’s best to package beer as soon as it’s cleared and the checks passed. Tanks where beer has been filtered or centrifuged, can also be re-filled several times before it needs cleaning.

As you’ve filled the BBT with “clean beer” only; there’s no sediment left behind when the tank becomes empty. Refilling saves on CO2, cleaning chemicals and labour.

Furthermore, most BBT’s are equipped with a sight gauge, meaning you know how much beer is in the tank. Most uni and horizontal tanks don’t have these sight gauges. Sight gauges help you keep a more accurate beer inventory.

Brewery Cellar Tanks Guide – Conclusions

As we said at the start of our brewery cellar tanks guide, the tanks you source for your brewery depends on the beer styles you intend to make. As lager becomes more popular with craft beer drinkers, horizontal tanks are worth considering. If you plan to brew them.

When it comes to brite beer tanks, if you unsure how many you need. A good guide is 1 BBT for every 4 FV’s you have. It’s just a guide, but fairly standard in the brewing industry.

We’ve one more tank type we should explore; serving tanks. These tanks deserve their own dedicated article.

As there are several options to choose from. We’ll do deep dive into serving tanks in part three of tanks article series.

But for now, thanks for reading and happy brewing!

If you’ve an and questions of feedback concerning this article, please feel free to comment below or email me at: neil@asianbeernetwork.com