Under Pressure

Bar-top boxes for Top-Pressure dispense

In my previous and rather lengthy article about cask-conditioning, I touched upon the limited shelf life of cask ale. I also mentioned how careless handling and disgusting practices, such as returning “slops” to a cask, had led brewers to look at ways to improve and maintain the quality of the beer, as served to the customer in his or her glass. 

The development of “keg” beers, filtered, pasteurised and then stored in sealed containers, and dispensed, under pressure, using carbon-dioxide gas, was one solution, but it was expensive. The equipment needed for processes such as filtration and pasteurisation was not cheap, so brewers looked at an alternative “half-way house” solution in the form of “Top Pressure” systems.

Top Pressure dispense systems undeniably improved the keeping qualities of cask beer, and extended its shelf life. It stands to reason that if oxygen is excluded from the cask, then the contents will last longer, as oxidation cannot take place so, to many brewers and publicans, top-pressure seemed like the answer to a maiden’s prayer. 

As above

There was a downside however, as in order to force the beer from the cask and up to the taps on the bar, it was necessary to apply an appreciable amount of pressure. If there was a long pipe run from the cellar to the bar, a considerable amount of pressure was necessary in order to dispense the beer and due to some of the CO2 being absorbed and dissolving in the beer, this had the unfortunate side effect of making the beer fizzy. In the worst cases, the beer absorbed so much CO2 that it resembled keg, rather than cask beer.

When I started drinking in the early 1970’s (not at a legal age to begin with), top-pressure dispense was pretty much the norm; in fact seeing hand-pumps on the bar, and especially ones still in use, was quite a rare sight, apart from in Shepherd Neame pubs, and my friends and I tended to avoid those anyway. 

CAMRA too in those days, viewed pressurised dispense with as much disdain as it had for keg beer, as a look through the Brewery Section at the rear of the 1974 GBG reveals. Many of the pub descriptions in the main part also specifically refer to “pressure”, or the absence of it. The Guide goes out of its way to point out that “There is always a very high risk that the beer will become gassy, sickly and sweet it carbon dioxide is re-introduced artificially”. I understand the bit about the beer becoming gassy, but sickly? And as for sweet, well CO2 obviously possesses magical properties, hitherto unknown to chemists!

One could therefore be forgiven for thinking that top-pressure was an inherently bad system, and yet it was brought in by breweries to address a major concern regarding the poor quality of much cask beer. The brewers argued that as carbon-dioxide is a natural by-product of fermentation, its use as both a means of dispense, and in providing a protective “blanket” over the beer, should be considered beneficial. One could see their point, and almost sympathise, especially as they were trying to solve a problem which had dogged cask beer for many years.

The point about providing a blanket was taken further by a number of breweries in a hybrid system known as “blanket pressure”. Here, CO2 under low pressure was applied to the top of the cask, via the spile hole, in a similar manner to that of normal top-pressure systems. The pressure of gas was kept deliberately low, so as to just provide a layer of protection to keep air away from the exposed surface of the beer. Dispense would then be achieved by normal hand or electric pumps, or even by gravity.

Cask-Breather

As carbon-dioxide is heavier than air, the logic behind this works well but, as might have been expected, CAMRA were vehemently opposed to such systems, as they claimed the blanket of CO2 above the beer prevented normal conditioning from occurring, and if the pressure applied was too high, excess gas could dissolve in the beer making if fizzy like keg.

The so-called “Cask-Breather” was a device specifically designed to circumvent these alleged problems. Cask-breathers are, in effect, demand valves, which work on similar principles to the aqualung, used all over the world by divers; although the former operate at lower pressures. The principle is that as beer is drawn off from the cask, the inside pressure falls. Instead of drawing in air, the “breather" allows sufficient CO2 to enter the cask to fill the volume created. The beauty of it is that only just enough gas is admitted, so there is no chance of excess CO2 being absorbed by the beer. 

How the thing works

Despite the device having been evaluated and approved by  CAMRA’s Technical Committee, with an irrationality based solely on a rabid aversion to the dreaded “extraneous CO2”, the Campaign as a whole said “no”. The chance to improve the quality and longevity of cask beer was therefore lost due to the rigid dogma of a handful of “stick-in-the-mud”, diehard activists. Not that this opposition stopped brewers and publicans alike installing cask-breathers in their cellars; a move which didn’t go un-noticed by CAMRA purists, and which led to an insistence of the right to inspect pub cellars, when surveying entries for the Good Beer Guide.

This confrontational approach obviously upset a lot of people in the trade, and did little to enhance the standing of CAMRA as a responsible and professional organisation. The cask-breather debacle also marked the beginning of my long-standing disillusionment with the Campaign, and this insistence on cellar inspections was one of the key reasons why I no longer have anything to do with the Good Beer Guide.

Looking back, I can understand why brewers opted for the top-pressure system as a means of improving the keeping qualities of cask beer, but was CAMRA right in opposing it? Probably yes, due to the risks of altering the mouth-feel and drinkability of the beer due to the absorption of too much CO2. As for blanket pressure, I don’t really know. What I do know though is that had devices such as cask-breathers been around in the late 1960’s-early 1970’s, then top-pressure systems would have been unnecessary, and cask ale could have continued pretty much as it was, without the need to switch over entirely to keg.

Cask-breathers in use

In my book, the brewers were definitely right to look for ways of extending the life of cask beer by preventing oxidation, for this is the Achilles Heel of “real ale”. All is well if a cask is emptied within a two to three day period, but as we all know to our cost; this is often not the case. Many pubs are far too ambitious in the number and types of cask beer they stock, leading to a slow turn-over, especially of the less popular beers or brands. Right from the start, CAMRA did recognise the inherent limited shelf-life problems associated with cask beer; that first commercial, pioneering Good Beer Guide which appeared in 1974 had a few lines in the introduction which read, “Another feature of real ale that you ought to welcome is that it can vary from superb to undrinkable; even in the same pub. Every brew has its good days, its bad days and its indifferent days. Learn to accept the off moment and revel in the times when you hit on a really excellent pint”. (I don’t know about you, but I’d be very wary of a pub where the beer was excellent one day, and undrinkable the next! Surely a case of someone not knowing what they are doing?)

The frustrating, and indeed annoying thing is that when a solution to this problem appeared in the form of the cask-breather, because of the influence of a small group of vociferous, die-hard activists, CAMRA chose to turn its back on it. For purely doctrinal reasons associated with past negative experiences of top-pressure, the Campaign went into overdrive in its opposition to this “beer saving” device. These reasons flew in the face of scientific facts and demonstrably repeatable tests which proved, beyond all doubt, that cask breathers had no adverse effect whatsoever on the beer.

Mind you if Carbon Dioxide really can make a beer taste sickly and sweet, then perhaps anything is possible and cask-breathers are the work of the Devil and the very end of civilisation as we know it!

Footnote: I wrote a similar post to this one, back in April 2014, highlighting the lunacy of CAMRA's opposition to cask breathers. You can read it here.