Casks and KeyCasks were filled with the same beer, direct from racking tank, as is usual. Rather than send them out the following week for you lot to enjoy we tucked them away in the corner and allowed their shelf life to expire (8 weeks). This was done with two beers, one a 2.8% tiddler, the other, Seasider. Now we run a clean gaff here (I just got the latest, spotless lab results back) so I would not expect the beer to 'spoil' in anyway - it is sitting in sterile, hermetically sealed containers at a low temperature (12ºC). I would, however, expect a diminution of hop aroma and a lack of zinging freshness on the nose.
Prior to test day the vessels were vented for 48 hours and the casks tapped. I hooked them up in the cellar to two, freshly cleaned beer lines. Bert poured samples in the bar, not knowing which was which. It was a 'double blind' test. The moment had arrived - I was presented with three glasses of beer and challenged to sniff the odd one out. "Look, I'm happy to do this for you, but I will not offer an opinion on which is best, if there is a difference" I said to the Dutch genius. Immediately I sniffed the samples I changed my mind - I snorted the odd one out a mile away, plain as my nose. We repeated the exercise with the Seasider and again, there was a massive difference.
The cask versions were just a little tired on the nose, lacking bright, fresh zip, the individual components melded into one.
The KeyCask version was a different prospect entirely - bags of freshness, as if it were a week old, in youthful its prime.
There you go then, a vessel designed as a keg, used as a cask and superior to a cask in terms of retaining beer quality.
Put that in your pipe ans smoke it.
8 comments:
Eddie, in which way is a KeyCask different from a KeyKeg? I´m already using KeyKegs in the same way that you do. Does the beer come in contact with air when conected to the beer pump?
So, if I were a pub landlord and I wanted to try a new beer, it sounds to me like I wouldn't have to make a decision on a "safe" beer that I know would sell out in 3 days and could take a beer that might give me an edge over my competitors, then?
What do you think is going on in the cask? If it's sealed and clean, with minimal headspace (just like the "keyCask"), what do you think the mechanism behind this subtle spoilage is?
Bruno - no difference except: secondary fermentation in KeyCask quite low and served through a handpump. We used an adapted connector to vent the beer. Air was allowed into the sphere whilst serving. It worked really well.
Sean - indeed, but you still have beer sitting in the line and engine, places it doesn't like. Can't beat good turnover.
Strings - I've been mulling that over and I note the 'open' aspect to cask filling. There's air in the cask and there will be some O2 ingress, however small. We've changed our filling practice now to try and fob the last bit so at least there's no air in the cask after we've filled. It would be nice to be able to pre-flush with inert gas though. The assumption has always been that the yeast uses up the O2 but our experience suggests that isn't entirely the case. Fascinating, surprising stuff.
Brilliant, you're pushing things forward with experiments like this.
"I note the 'open' aspect to cask filling. There's air in the cask and there will be some O2 ingress, however small."
So that's adding to staling, but why would that lead to hop aroma and flavour falling away?
"We've changed our filling practice now to try and fob the last bit so at least there's no air in the cask after we've filled. It would be nice to be able to pre-flush with inert gas though. The assumption has always been that the yeast uses up the O2 but our experience suggests that isn't entirely the case. Fascinating, surprising stuff."
Like when you cap on foam when bottling. That is very interesting because I've always read the same, that the yeast scavenges that last bit of 02 when you prime a cask or bottle. An empty bag holds no Oxygen I guess, so no oxidation can take place.
In Prague/Pilsen we saw the PU Tank beer which is basically like a giant key keg. A bag within a metal tank, air pumped into the outer area to crush the bag and push the beer out. I've not encountered such scrutiny for beer storing and serving as we saw at PU ... if a key keg is good enough for them, it should be good enough for anyone. (Mark just wrote a bit more about this at Pencil&Spoon).
Doesn't the movement of the bag disturb any sediment?
Hi Eddie, I'm curious to give this a go can you adapt a normal keykeg connector to allow air into the bag? We've already got 2 cask lines ready to serve keykeg, we pinched the idea from Ian at the grove but I didn't realise you could actually vent the bag.
Mark - I find cardboard hides hops rather easily, perhaps even before it is readily detected?
And yes, I have 4 x 1000 litre cellar tanks working on the bag-in-tank principle. They're very common in the Dutch 'pub' industry as dispense vessels.
Barm - no, not in my experience though I have a good friend who would beg to differ. We found we could empty the thing to the last drop almost. Of course, we're extracting from the top so the beer is gin bright very quickly too.
Jonny - yes, you need to remove the one-way valve from the gas side in order to vent the ball first. Then open the bag-side valve and hey-presto! you're venting away. Remember to leave the ball side open during service.
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