Friday, August 12, 2011

The Physics

Professor Branestawm called us into his workroom earlier today.
"See here!", he cried, indicating what appeared to be an old television set balanced precariously on top of what we first took to be an old refrigerator, but closer inspection revealed as a VAX 11/750. "The Internet!" he gesticulated at the screen, "The world wide web!".

And sure enough, the good professor was pointing at a shaky image of Hardknott Dave's blog.

"Very good Professor..." and with placatory smiles, we edged back towards the door.

"No, no," he laughed, "I'm quite familiar with your Internet nonsense, thank you very much. I merely wished to draw your attention to this debate about cooling!"

"See here", he continued, "one of these Internet characters holds that beer lines should be cooled along their length, while another proposes that the cellar temperature should be lowered during the warmer part of the year."

"Internet characters?", I burst out, "Professor, those are real people you're talking about!"

"Indeed?" He looked over one of his many pairs of spectacles, "So you say. I should like to see you prove it. However, that's for another day. Shall I continue?"

"Please, professor, do." We made ourselves as comfortable as possible on piles of old DEC manuals. Mine had a scrap of paper on top which bore only the words "BELL END". I held it up. "Professor? Is this important?"

"Ah, thank you." he took it from me and forced it into an already packed drawer, which he closed with a few smart mallet blows. "That's the last part of my halting problem proof. Marvelous things, these computers".
"Now see here," he went on, and once again pointed at the screen, "If we cool the beer line directly, we can remove the heat picked up along it's length."
He laughed, "Or to put it another way, we can add coolth to cancel out the warmth".

"Coolth, Professor?", once again, he'd lost us.

"Certainly!" And he made his way to the door where he flicked a switch. Instantly, the room was plunged into darkness. His voice came out of the gloom. "Behold! The electric dark bulb!"

"Professor!" I exclaimed. The workroom was dangerous enough in the light, stumbling around in the dark might be lethal. "For goodness sake turn it on!"

"Off, you mean", he laughed. "Although, oddly, it consumes far more power off than on!". But he relented, and continued. "I'm pretty sure that it requires less coolth to keep a beer line at the right temperature than to super-cool a pub cellar. Indeed, if we do cool the cellar below the beer serving temperature, we're using the beer itself as a coolth transfer fluid, in an uninsulated tube, to lower the temperature of the dispense equipment."

He smiled, "By coolth, of course, I refer to the power required (running the chillers, or air-con, or cellar coolers) in order to remove the excess heat and push it out of the building."

He opened the front of the old VAX 11/750 and revealed a mess of wires, some brazed copper tubing, a bare motherboard and some bottles. He got a beer for each of us.
"I've converted it into a fridge, that's an Intel Core i7, and I'm overclocking it big style".

"Bottoms up Professor!"


Barm said...

Perhaps it is time for someone to invent a super-cask with a built-in cooling jacket, similar to the cylindro-conical fermenters that have done away with the need to keep lagering cellars at –2ยบ C or whatever it is.

Flagon of Ale said...


I was genuinely interested in that conversation about lines and cooling etc. The cask market here in America is very primitive. Also what Barm says: they make that sort of thing:

I wonder if many places in the UK use them? Sounds like no.

StringersBeer said...

I was in a cellar last week where the casks / kegs were in home-made(?) jackets with cooling such that they look like short daleks.
You can get stuff like this.

Of course, you've still got to keep the beer that's waiting to go on service cool. So they're not a complete answer.

I might be wrong, but I think there used to be a metal cask that had an integral water jacket. Heavy and prone to damage I'd think. I wonder where I read about it? Or maybe I dreamed it.

Barm said...

Yes, I would think they'd be heavy and prone to damage too, as well as expensive and not much use if you still have to cool the cellar for the ordinary casks anyway. Conical fermenters tend not to get thrown about as much as casks, obviously.

StringersBeer said...

P.S. Flagon of Ale, I wasn't meaning to make fun of the conversation. In a traditional pub, there's usually a decent sized cellar, decent sized I say, but sized for the traditional trade. In the old days this would have been cooled (a) by virtue of it's location i.e. underground, and (b) by liberally hosing water all over the floor, and trusting to evaporation. Physics tells us that in the summer the beer would typically be a bit on the warm side. And possibly a bit cool in the winter.

Nowadays it's possible to be more consistent than this. If that's thought to be important.

I think the point the Professor was making (he does ramble on a bit) was that if you want to cool your dispense equipment, using the beer to do so is likely to be rather inefficient and incur higher running costs. You're cooling the entire (non-airtight) cellar, just to cool a few yards of line and the pump cylinder. He's agreeing with Dave.

It's not hard to cool a room, or even a large cupboard, down to a good temperature. We use domestic air con (with a bit of jiggery pokery) to get our little cold room down to 10°C no problem. If asked, I'd recommend vertical extractors, particularly my favorite, caskwidge. Then you don't even need stillaging / autotilts. Also there's less scope for spillage.

But I'm not a publican, and they all have their own opinions based on years of practical experience. That said, they're quite a conservative breed.