Cask beer aspirators, my opinion!


Wrote this before I realised it had already been covered,“Cask breather or Aspirator ” but never mind. The debate about using co2 as a top pressure on cask ale seems to polarize most drinkers. From a technical point of view and speaking as a technician of 40 years standing, I see the advantage of supplying a maximum top pressure of say 2 psi, to casks. It will prolong the life of a cask beer, keeping it in better condition than if a cask is just left open to atmosphere. Having installed many aspirated systems as they are called, I cannot think of one instance where there was a negative affect.

The affect of using a co2 top pressure is to exclude air born bacteria from the cask and not as some people may think to push the beer from the cask. Aspirators do not turn cask beer into keg beer.


However there is another valid argument used by lots of real ale buffs which runs along the lines of keeping things the traditional way and not introducing any system that is not traditional. This may from an aesthetic point of view be valid but practically speaking how many cask beer drinkers would know if a cask beer was using a co2 top pressure or not. My personal feeling is that there is no disernable change in the taste or character of cask beers using aspirators.

Cask Breather

Using aspirators is viewed as sacrilege by some and unnecessary, but I do not agree, I think they are an integral and perfectly valid part of cask beer dispense and not just a gimmick to save the landlord money. I am unaware as to the CAMRA view on aspirators and would welcome there opinion on this contentious issue.

If after reading this article you are persuaded to give it a go, you will find the cost of installing this equipment is very reasonable and your local brewer may even pay to have it installed.


Does a cask breather or aspirtator really affect the taste of the ale

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  1. CAMRA view is very simple. Use aspirators (aka cask breathers) and your pub will be ineligible for entry in CAMRA guides (including the Good Beer Guide) and awards. CAMRA believe that the top pressure does change the character of the beer by the additional CO2 absorbed.

    • CAMRA talk a load of rubbish on this subject. There is a lot of brewers out there who store beer in conditioning tanks with a blanket of gas at higher psi than a cask breather but CAMRA turn a blind eye on this to suit themselves.With beer kept like this the so called damage has already been done before the beer gets to the pub. I have tried discussing this with CAMRA but they won’t talk about it.

  2. Using a cask breather is effectivly masking a slow sale issue.
    If a landlord is going to sell cask ale they have to comiit whole heartedly. Offer free samples use in food , have blackboards up in the pub . The key to cask ale is rate of sale , containers on sale for longer than 72 hrs simply give consumers a poor experience and consumers dont order again and go else where. Brewers need to stop talking up the benefits of breather and aspitators and focus on Rate of Sale – bring back Pins or help landlords drive ROS

    • The moment oxygen comes into contact with beer it starts to spoil it. At any given point (including within the divinely revealed 72 hours) a beer that has not been exposed will be better than one that has been exposed. I am a CAMRA member by the way.

      The CAMRA position is simply wrong, your argument above is typical of the contorted logic that is applied to back up an argument which is simply irrational.

  3. Suhuy …Why would you want to use nitrogen? Its CO2 that helps to keep things fresh.

    You could say you are giving a poor consumer experience after 24hrs because that is when beer is tasting its best. All an aspirator does is keep the beer tasting fresher (the operative word being taste) for longer, so if it keeps the beer tasting fresh on day 2 3 or 4 it has to be a good thing. The condition of the beer and whether it on sale or not is up the Landlord. Give the Landlord some credit. 72hrs is a rule of thumb anyway some don’t last that long some go longer more often or not it depends on the alcohol content.

  4. I’ve sometimes had to wait 5 days for an ale to clear bright. Some taste green and unconditioned after the recommended vent time despite being crystal clear. I don’t use ventilators, I soft spile when conditioning / on sale and hard spile when conditioned / off trade. I would however fully endorse the use of ventilators at the discretion of an experienced cellarman as their experience will decide whether the ale is good for sale. Attentive landlords and CAMRA members alike should be interested in extending the quality of an ale whether this be by manual attentiveness or technological advance. We’re not talking about preservatives! 48hrs, 72hrs or however long after sale, all ales are different and taste should be the decider, not the date on a sticker or a single piece of cellar kit.

  5. We have a breather that removes oxygen from the air stream. It needs no back pressure and removes oxygen as it is drawn in to the keg. This leaves Nitrogen as the space filler at atmospheric pressure. Being that nitrogen is 80 times less soluble in liquid than CO2 then this drastically reduces risk of flavour change to any beer.

    • Hey Ian, Tell it to Camra.Unless this device is made from wood and was made in the Middle Ages, then they will not approve of it.
      Not sure they like electricity.

  6. just a quick question
    why is it not easier to ron a pipe from your flowjet pump taking advantage of the co2 that is discarded as you pull a pint

    • I regularly use flowjets to move beer around my microbrewery, they usually need at least 20 psi to start moving product ( depending on the length and size of line ) – the type of CO2 blanket being talked about here is a maximum pressure of about 3 psi. I’m not sure what the exhaust pressure of a flowjet is, but I’m guessing it’s probably equal or close to the input pressure. You might be able to store it and run the aspirator system via a secondary regulator .. Hmm got me thinking now.. thanks!

  7. If you are using gas pumps then it is more practical and economical to use compressed air. Air compressors suitable for gas pumps are relatively cheap and would be a lot cheaper than using bottled gas.

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