Three Cask Ale (semi)Fallacies

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[There is a followup to this post based on the extensive discussion that occurred around it on Twitter.]

This is in response to Ed Razzall’s cask ale cellaring tips. I write it because in the post and comments items arise which are persistent cask ale fallacies. (With some minor updates since original writing, including insertion of “semi” above!)

  1. Myth: “Oxygen is needed for conditioning”: It is often heard that oxygen (O2 in air) is needed for cask ale to “start working” i.e. begin secondary fermentation. I encourage anyone who believes this to go ask a proper brewer, or learn some of the science/(bio)chemistry of brewing! (The latter may be safer… if you do ask a brewer if he likes O2 anywhere near his beer do it from a safe distance.) O2 contact with beer post pitching of yeast is BAD. The initial aerobic phase of fermentation that needs plenty of O2 in solution is for breeding yeast cells and after this phase O2 is not desirable. This healthy cell population then start munching yeast until the beer is ready for secondary/conditioning. Yeast does not need O2 in the conditioning phase, it will munch sugar and fart CO2 quite happily without O2, it will mop up diacetyl without O2. Look up the Embden-Meyerhof-Parnes pathway [Ref: I recommend reading Principles of Brewing Science]. The only thing O2 will do to beer once it has come out of a brewery is RUIN IT and make brewers cry. (With an exception for those drinkers who like cardboardy oxidised flavours to “soften” their beer… that’s a matter of taste… *mumblepervertsmumble*)

  1. (Partial) Myth: “rouse the yeast”: (See update below.) Many seem to believe that before stillaging & venting you need to “rouse the yeast” to get it into suspension. I’ve heard this often and I don’t understand it at all. The cask has been manhandled onto a lorry/van, driven over bumpy English roads, and then tossed down a hole (cellar). So even if it needed “rousing” I’d say the job is well done already. But… does it need rousing? Why rouse it? To get yeast into suspension so it can “work” possibly? Even if the beer needs to “work” more (see next myth), shaking it up isn’t going to improve things much – there will be plenty of live yeast in suspension already. There is another factor here to consider: finings. Finings aren’t forever… in time their usefulness degrades (note that usually unfined beers come out of the brewery with longer best-before periods). The effectiveness of finings also degrades between them having to work. I.e. if you keep “rousing” the yeast the finings get “tired” and the beer takes longer to drop bright and the trub layer will not be as “tight”. [Ref: Cellarmanship 5th ed. page 99.] “Rousing”: at best achieves nothing, at worst means you’ve got to wait longer for clear beer. Now, Ed likes to stillage his beer for a good long maturation phase. So his rousing isn’t likely to matter one way or the other. He’ll end up with clear beer because he gives it plenty of time. Even good unfined beer should drop bright eventually.


    UPDATE 2014-05-13: There is additional complexity here regarding the isinglass finings used to help nearly all cask ale drop bright. As in James’s quoted Tweet above finings are more effective past the first drop. If the brewer fines as casks leave the brewery and delivers straight to your pub you’ll possibly be on the 1st drop, if the brewer fines at racking you’ll be on at least 2nd drop, if you’ve gone via a distributor you’re probably past the 2nd drop. The danger is that if you’re not at least at 2nd drop you could have a higher ullage. My suggestion here is that you get to know your brewer very well and ask their advice – if they’re fining as the beer leaves the brewery then there is some evidence to suggest that you could do with a good old rousing! But: If in doubt I would not rouse… because you just don’t know where you’re at and if you go over that critical 5th drop then there is a chance the cask will simply not drop bright at all. I’ve not found any good references on this feature of isinglass finings but will try and do so.

  1. Myth (mostly): “secondary occurs at the pub”: It is perhaps a legacy of historic practices that people believe breweries ship beer to pubs before substantial secondary fermentation has occurred. I hear this still happens sometimes… but in almost all cases: no. Most breweries do their best to ensure secondary has progressed sufficiently before the beer leaves the brewery. This is by the demand of the modern pub market which, for better or worse, often wants beer ready to serve within days of delivery. Historically this was not the case… which is why I think this myth persists in the collective “cask ale” memory. I mark this myth as “mostly” as every now and then I’ve come across beers that are “working hard” (enthusiastically fermenting) in the field. Plus secondary fermentation abates gradually, whilst the important fermentation phase will be complete by the time the beer reaches the pub yeast activity will not have ceased entirely. I also know that if you’re on a tight schedule to receive beer a brewer will sometimes let it out early – making it clear it won’t be ready to go to pubs/vent for a few days. I’m guessing there may be some pubs that have this as part of a regular relationship with some brewers they know (but that is only supposition).

None of this means Ed’s beer isn’t good. I suspect it is actually very good despite the myths. Because Ed likes to give his beers a good long time on stillage it’ll be bright regardless of rousing. Because beer ejects CO2 when vented very little O2 will actually manage to get into the cask to contact the beer – and note that Ed seals the cask airtight once it has stopped noticeably ejecting CO2.

In fact the impact of the fallacies in Ed’s cellaring is insignificant compared to the GOOD he does. Sanitisation! The puzzled looks I’ve had from people responsible for caring for cask ale when I ask about sanitising shives/keystones/taps/spears/etc scare me. Hard pegs! When not being served seal up you casks! Two things happen if you don’t, 1) more CO2 escapes: flat beer; 2) more O2 gets in: oxidised beer. TIME! Ed only serves his beer when he thinks it is ready, it doesn’t go on as soon as it looks right, it goes on when it smells and tastes right too. He gets to know his beers and learn what the right timing is for them. This is the skill of a good cellarperson. I bet his beer is the best for miles.

So the myths do not mean that no “cellarmanship” is required. Far from it! “Condition” in beer comes from secondary fermentation but the process of “conditioning” includes proper venting and maturation at the pub – you need all of these done well to end up with a pint “in good condition”. We need more cellarfolk with Ed Razzall’s interest and attention to detail.

Of course – you only have me saying all this. I am not a a pub cellarperson, so from what point of authority can I speak? I’m an analytical nerd, a researcher and a learner, a computer “scientist” with a foundation of engineering which came with a solid dose of physics and chemistry. I homebrew a little, but I’m not a great homebrewer. I talk to real brewers and bother them for knowledge when I can. I read… reading is useful. I’d recommend two books out of those I’ve read: the imperfect Cellarmanship and the deeply technical Principles of Brewing Science. I’m a CAMRA “cellarperson” and care for cask ale at festivals, I’ve done the week-long CAMRA Bar Management training at GBBF under the guidance of many key CAMRA technical folk and the direct tutelage of Buster Grant from Brecon Brewing (a Heriot Watt educated brewer). I’ve recently done the 2-day Beer Academy “advanced” course with the excellent master brewer Derek Prentice. I deal increasingly with brewers and breweries – buying/managing beer for CAMRA and now as part of my own small beer distribution business.

The best from-the-brewer’s-mouth advice on the topic I know of on the web comes from Justin of Moor Beer. Justin sells his beer unfined… and prefers a slightly different method to the usual (vent first, tap later), but much of his advice applies just as well to fined beers and either venting/tapping order: Cellar Management Tips – if anyone can point me to similar quality advice published by other brewers I would be grateful. There is cask-ale.co.uk – but it pushes this “redistribute the finings” idea which I find dubious (see update above on when rousing my be a good/bad idea), and I have trouble trusting any source of information presented in such an eye-watering colour scheme. UPDATE 2014-05-13: This is a thorough guide to cellarmanship by the respected Mark Dorber, Ed’s teacher and boss: Cellarmanship & Real Ale – which is good, but still not entirely in agreement with brewing professionals I know (conflict around yeast rousing and where/when secondary occurs remains).

I can take as good as I give… I’m a scientist not a believer, so if you have some evidence to say any of my myths are not myths I will consider it. It is a complicated subject and my own education is far from complete.

Update 14-05-2014: Much debate ensued, but it veered far and wide off-topic. Most of this is lost in Twitter (for the better), but some debate is recorded on Boak & Bailey’s blog: TRADITION AND SCIENCE IN THE PUB CELLAR

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