Monday, 23 August 2010

Appropriateness of beer technology

At the Great British Beer Festival I was invited to the Tasting of Fullers Brewer's Reserve No2, and a damn fine beer it is too. I had already been drinking a few beers of the Bières Sans Frontières and am still not convinced I have fully appreciated this beer, nor do I remember the exact detail of the talk John Keeling gave. I have a couple of bottles here so I will try to rectify my lack of full appreciation on another occasion, just so long as I don't do what I did last night and weigh into a bottle after the pub, when my palate is half shot.

Whilst I can try the beer again, what I always fail to do when listening to great brewers talk is remember all the detail of the brewers knowledge. John talked about the technicalities of bottling barrel aged beers, not a subject I'm completely incompetent at, as the success of Æther Blæc has proved, but I'd be a fool if I even pretended to know as much about the microbiology of beer as John does.

I seem to remember John talking about the brewers reserve No2 being a little more susceptible to Brettanomyces generated flavours as brandy has a lower ABV than whisky at cask strength. Actually, I can find no evidence that cask strength brandy is any weaker than cask strength whisky, so I may have misinterpreted1 this point.

Whether specifically about the No2 or generally about barrel aged beers the point about the microorganisms in the wooden cask is important. John indicated that to enable the beer to be stable after bottling, chill filtering is required, and the beer reseeded with yeast. Although I don't chill filter I am very careful to get very good, recently emptied, long matured whisky casks for my whisky aged stout; this ensures as sterile an environment as possible before the beer comes into contact with the spirit soaked wood. Storing in as cool an environment as possible during maturation is also important.

I know of beer commentators who are horrified at the idea of bottle conditioned beers being re-seeded with yeast. Some purists think that the only correct way to make bottle conditioned beer is to chance the yeast from primary fermentation being strong enough to ensure secondary, anything else is cheating. This could not be a more erroneous point of view.

It is also worth referring back to a post by Zak Avery about beers that go wrong, the dicussions in there about Brettanomyces and a suggestion about pasteurising is interesting; every brewer has to consider what is best for their beer and moreover may not get it right every single time.

I would never make a bottle conditioned beer that wasn't first cleared in conditioning tanks, or perhaps a whisky cask, and then re-seeded and almost certainly primed at the bottling stage. I choose to use finnings where appropriate to clear the beer. Chill filtering may well have advantages to ensure unwanted spoilage microganisms are removed. I understand that Thornbridge have a shiny new centrifuge2 which should remove these pesky little guys but leave the flavours much more intact.

I suspect that any good bottle conditioned beer will undergo some form of treatment indicated above. I certainly re-seed every bottle conditioned beer I make, it's madness not to.

This makes me wonder about the "fizzy chemical beer" mantra that occurs in some circles. The use of modern techniques and equipment to ensure quality beer doesn't mean the beer is not a high quality worthy product. It does not mean that re-seeded bottles are inferior to the purity of a bottle that depends on the primary fermentation yeast, quite the reverse. It does not mean that a keg of unfiltered beer is somehow inferior to a poorly kept cask of some poorly executed clone of yesteryears mild, quite the reverse. It does not mean that a week old cask kept under a gentle blanket of carbon dioxide is inferior to a 3 day old cask of the same beer even under ideal cellar conditions, quite the reverse.

As we improve our brewery and our abilities we will be turning to technology to help us out at any point we feel it is appropriate, we hope it will make our beer better and better and better. If it loses us points with the purists then so be it.


1I sometimes wonder if my honesty is what keeps me from getting any paid writing roles; after all, a real journalist wouldn't be caught admitting that the story might not be true.

2Look in the comments in this post.


StringersBeer said...

Quite right Dave. I hear that removal of primary yeast (usually by centrifugation rather than filtration), followed by reseeding in the bottle is a common practice. I seem to remember reading that many of those rather well thought of Belgian beers (Chimay, Orval, Rochefort, etc) are done this way. I'm not clear how we could expect to get consistent numbers of healthy yeast & the right amount of fementables into the bottle otherwise.

Sterile filtration has been shown to have some quite detectable effects (-ve colour, bitterness) on the beer. Of course, knowing this, I suppose it's perfectly possible to brew taking it into account, i.e. amp it up a bit over what we'd do for cask.

And don't centrifuges cost a big lot of money? So this is a technique restricted to the well-capitalised.

Who are the commentators "who are horrified"? They sound a bit daft to me. Or maybe they enjoy the RAIB roulette as they open first a "gusher", then some flat infected muck, in the search for one that's actually fit to drink.

MicMac said...

This subject is a really fascinating one for me - if it's not bad blog-comment etiquette, can I cut&paste my comments from Zak Avery's blog on a closely-related subject -
To me the 'real' (not literally :~) elephant in the room is that CAMRA's definition of RAIB bizarrely excludes Thornbridge (seemingly specifically because the bulk of condition in the beer is created in the CCFV before it reaches the bottle) yet includes the bulk of the big name RAIBs which are in supermarket & winning Champ Bottled Beer of Britain awards are actually sterile-filtered before being reseeded with fresh yeast (& possibly also primed with some form of sugar).

Why is this important? Well it's not necessarily - I've drunk beers that have been through all sorts of processing & come out the other end perfectly fine (I'm told US craft-brewing veteran, Anchor's beers are all pasteurised, yet I love them when I drink them). I'm not sitting on the fence here - by and large my beers of choice are cask & unfiltered, I would agree with Zak - generally fresh is best, but I'd go further & say generally unfiltered is best too.

What confuses me is CAMRA's acceptance of practices in bottled beer production that they would abhor in a cask beer.

Sadly this (albeit correct) re-definition of Thornbridge's bottled beer as not bottle conditioned might put some people off drinking it, yet, to me at least, they're actually *more* natural, being unfiltered than many of the ones with the little CAMRA logo on them.

Alistair Reece said...

If I read Zak's comment correctly, Thornbridge follow the spunding method from Germany?

Without the acceptance of technology we would still be brewing without hydrometers, thermometers, whirlpools, heat exchangers and myriad other equipment that we take for granted.

Anything that improves the beer is fine by me, and yes (shock, horror) that includes cask breathers.

Ed said...

The last brewery I worked at filtered and reseeded the bottled conditioned beers but I'm not doing that in my current job as we don't have the kit.

I think CAMRA stick with their definitions as they go by what they can see: is it on a hand pump and do the bottles have sediment. Obviously there are limitations to this but at least it gives us beer bloggers something to whinge on about!

MicMac said...

@StringerBeer/Steve - I meant to say - I've never heard of another UK brewer producing bottle-conditioned beers using a centrifuge & not sterile filter.

Re getting the right amount of healthy yeast & fermentables - both of these can be done with some lab kit, but the simplest answer is to remove the old yeast & replace it with healthy new yeast at the right rate.

I have the kit to do the other bit (to ascertain the amount of fermentabililty of a beer) in my loft & shed - it's a mixing table & an accurate digital density meter. The idea being that if you want to leave the right amount of fermentability for cask- &/or bottle-conditioning you test the wort attentuation limit of your fermenting wort & then arrest the fermentation at an appropriate point.

Re beefing up colour & flavour to account for possible losses through sterile filtration (especially hop flavour) - I've done exactly that & IME it works fine.

Yes I understand centrifuges are fairly big bucks.

& yes, I would much prefer that the RAIB world was not so full of beers that are infected, over-carbonated, flat, etc!

ChrisM said...

RAIB Roulette, brilliant :-D

As for yeast, it's all a bit witchcrafty for my engineer's brain.

StringersBeer said...

I don't see that there's anything wrong with newer technologies per se. But it always makes me worried when we apply technological fixes to problems that properly belong in some other domain. I suspect that the quality of some BCAs could be easily improved by some basic cleaning. A few years ago I bought a bottle of [unnamed beer] from a brew-pub. It was an absolutely central example of undrinkable muck. I know they tell you it's not easy to diagnose infection down a microscope, but this was a thick soup of short fat rods. You can still buy this beer, but now it's filtered. I suspect that they're still filthy brewers even tho' their bottled beers might keep better nowadays.
(But I hope the filters are taken away and buried at a crossroads at midnight with a stake through their hearts)

But of course, if you're calling it a bottle conditioned beer then we'd hope that much (if not most) of the conditioning has actually taken place in the bottle. Now, I know there are heaps-o-things we can do to make our process easier, but in this lark I like to think there's an element of doing things "not because they are easy, but because they are hard". That said, I'd have my beer filtered and carbonated after a proper maturation, and I suspect that this gets you closer to the stuff you'd drink in a pub (which hasn't been sitting on its sediment for months at any-old temperatures).

Unknown said...

MicMac, one of the powers of Blogging is the sharing of information and ideas. I don't think that copying and pasting is bad etiquette where it is relevant. Thanks for sharing it here.

Thanks everyone for the comments. I'd like to point out that I'd written this post the night before and scheduled for future publishing. I saw Zak's great post and decided to bring forward publishing.

I note that I condemn completely the use of primary yeast to ensure secondary fermentation whilst it seems Thornbridge do exactly that. I think it just proves that technology really can ensure that traditional techniques can be employed with great sucess.

In my opinion the Thornbridge bottles beers using their method are every bit bottle conditioned. Indeed, if fast cask(TM) can be "Real Ale" then Thornbridge bottles beer is RAIB.

Whorst said...

You are on the cusp on Proper Real Keg. I applaud you for this. Too many dipshits in the beer world that know nothing.