A guide to Beer Dispensing

By BottleShop Wholesale Manager Pete Brissenden

If you’ve visited our taproom and retail space on Druid Street over the last six months, you’ll probably have noticed some changes. We’ve installed a proper shopfront with beautiful, bespoke glass artwork. We’ve changed the lighting so we no longer have harsh, industrial fluorescent tubes. We’ve also had new toilets installed - no more portaloos (hooray!). Some of the smaller things that you may not have noticed include a new glass washer to speed up the turnaround on our glassware on busy Saturdays. We’ve also changed out till software to speed up service. The last parts of the puzzle to make the space the best we can are to chill all our stock, something we are working on with some custom fridges that will be installed soon, and a revamp of the beer cellaring and dispense system. We’re carefully considering what kind of system to install. Below, hopefully we’ll try to explain some of the decisions we’re making and why we are making them.
Cellar systems in the UK are set up to dispense filtered, pasteurised beer with low levels of carbonation which, for the most part, they do well. With a growing craft beer scene in which beers are largely unfiltered and have much more variable levels of carbonation, these archaic systems start to struggle. Hop particulate, yeast and proteins all cause huge issues.

Old style beer dispense system
Craft beer, compared to other beer categories, is expensive, both to produce and to buy for the publican. Any beer that isn’t poured for the customer is a loss. The old system of ‘long draw’ where a beer cellar is somewhere remote from the bar, runs through a cooler, then a chilled python to the bar and then to the tap, means there can be as much as three or four pints in a line. If, for example you have eight lines in your bar and you clean the lines once a week charging an average of £5 for a pint of beer, you are losing £160 every time you line clean. That is £8,320 a year in lost revenue, not counting the staffing cost. Coupled with high staff turnover and the loss of beer cellaring knowledge, it is easy to see how doing a regular, thorough job of it gets ignored. Ironically, if left, the situation often worsens, as yeast build-up in the lines gives beer places to nucleate, causing carbon dioxide previously dissolved in the beer to break out of solution, meaning fobbing, leading to more wastage overall than line cleaning.
The best system to avoid these problems is a short draw system in which the kegs are kept either directly under the bar in a chilled unit or in a cold room behind the bar that the taps are directly attached to the wall. These systems either hold the beer chilled at dispense temperature or use a small-bore heat exchanger like Brewfitt’s Future of Dispense system. This is what we use at our bar in Margate and what Gipsy Hill have just installed in their taproom, to reduce the amount of beer in the line down to around half a pint. The other beauty of the Future of Dispense system is that it allows you to adjust the flow rate through the heat exchanger, meaning that you can potentially have every line pouring at differing temperatures. We have all been to bars where an Imperial Stout has been served to you at 4 degrees and you’ve had to wait for it to warm up.

Beer dispense system guide
The other big problem with beer dispense the way it is currently set up in most cellars is that of gas adjustment. Most cellars in the UK are set up with a 60/40 mixed gas main ring and if they pour Guinness, one for 70/30. These numbers refer to the blend of Carbon Dioxide to Nitrogen. The idea behind using 60/40 gas in most cellars is that the addition of nitrogen reduces the likelihood of over carbonating beer in a direct contact keg. To explain this a bit further, we’ll have to delve into the realm of some basic physics. Henry’s Law states that "At a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid." Essentially, as a liquid cools, the more CO2 is able to dissolve in it. As things heat, the more energy the molecules have in them and the easier it is for them to break out of the liquid to being a gas again.

As most UK pub cellars are between 12-14 degrees with 60/40 gas installed, to get an averagely carbonated craft beer to pour without foaming, pressure has to be up near 40psi. UK gas systems are only rated up to 45psi, leaving very little leeway if the keg is slightly over carbonated or the cellar temperature fluctuates. Running the beer on pure CO2 does run the risk of over-carbonating the beer, but for applications where the temperature is higher, it allows better control over carbonation. The other missing part of the puzzle is the ability to easily and accurately adjust dispense pressures. Many cellars will have regulators without a gauge on them that are locked to one brewery determined pressure. As soon as a bar or pub puts a differently carbonated product on or, like with many small breweries, the carbonation varies from batch to batch, they are powerless to do anything about poor dispense and have to make do with fobbing and losses.
To make sure we are dispensing beer the best possible way we can, we’ll have a direct draw system with 4 different gas blends, individual line temperature and gas pressure control as well as holding all our keg stock at a rock steady 6 degrees. It opens so many doors for us to make sure we can play about with nitro beers, kegged cocktails, and beers of every strength, style and abv. Breweries are making huge progress on the processes in place in their breweries to ensure great quality beer. The rest of the industry needs to catch up now and ensure we are doing those beers justice by having a fit for purpose way of dispensing those beers.

With thanks to Jolly Good Beer for their technical input

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