C02 in Corny draft pour vs. Commercial draft pour

OK i've been wondering, us who keg homebrew, to get it right, usually wait days or weeks at a low PSI to get the right pour without too much foam.

However, once I was at a restaurant where I got a beer, and i told them it was flat. They did some fixing, and got another and it was carbed.

Then I think about the pub that says hold on the keg is out, i need to change the keg.

This all leads me to believe that these places are carbing as they are serving, correct? kind of like the soda machine deal?

Assuming my assumptions are correct...My question is, what technology are they using, and is it usable on our homebrew scale?

Just pondering....

Your assumptions are not correct.

The beer comes from the brewery fully carbonated already.

Assumptions are the mother all f up's.

So the brewery fully carbonates kegs? Good to know.

Still pondering how/why the restaurant that served me a flat beer managed to make adjustments and return to me a carbonated beer.

oh well food for thought. Thanks for the feedback.

Maybe they swapped a flat keg for a fresh/carbed one?

mmccurdy said:

Maybe they swapped a flat keg for a fresh/carbed one?

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Or they went to the other tap on the other side of the bar.:fro:

All i know is they were on the phone to the keg people...

Well, I know that the physical reality is that it takes time for CO2 to be absorbed into the beer. It's a function of the pressure, volume, and temperature. Higher pressure, lower temps, smaller volumes are better. Volume and temperature are not necessarily things that can be manipulated instantly. You can modulate the pressure right at the regulator, but there is still a lag period for the system (gas/liquid) to equilibrate. For example, it takes anywhere from 1-3 weeks to carbonate a keg of beer at fridge temps and "normal" pressures (some people start higher, around 20-40 psi for a short period of time to accelerate the process, but all end around 8-12 psi).

I don't know of any "flash" carbonation units like you describe, but I'm by no means an expert in commercial dispensing. It seems like it would be theoretically possible if they manipulate the pressure, volume, or temperature on the way to the tap (chill/carbonate a small volume continually, for example).

In terms of what they did on the phone w/ the keg people, I could see getting more foam/head on the initial pour by jacking up the CO2 pressure in the short run, but my guess is that it would dissipate quickly in the glass if it was not fully absorbed into the liquid. Beyond that, it's a mystery. Ask them if they have a carbonation secret? Seems like there would be a market for it if so...

My theory, based on seeing it happen at too many bars, is that a bartender poured a beer by mistake and that beer sat next to the tap for an hour or so until someone else ordered the same beer. The bartender took a straw and whipped some foam on the top of the beer and served it to the unsuspecting patron. If they don't complain the bar saved the money on a wasted pint, if they do complain the server looks like a hero for fixing the problem and providing a fresh, carbonated beer.

TokyoRoad said:

My theory, based on seeing it happen at too many bars, is that a bartender poured a beer by mistake and that beer sat next to the tap for an hour or so until someone else ordered the same beer. The bartender took a straw and whipped some foam on the top of the beer and served it to the unsuspecting patron. If they don't complain the bar saved the money on a wasted pint, if they do complain the server looks like a hero for fixing the problem and providing a fresh, carbonated beer.

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Last time I was at BJ's, the first pitcher was flatter than flat. The waitress blaimed it on sitting in the pitcher too long before serving. I wonder though because how is it going to stay cold that long?

badbrew said:

I wonder though because how is it going to stay cold that long?

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Toss it in the keg cooler or a refrigerator behind the bar.

TokyoRoad said:

My theory, based on seeing it happen at too many bars, is that a bartender poured a beer by mistake and that beer sat next to the tap for an hour or so until someone else ordered the same beer. The bartender took a straw and whipped some foam on the top of the beer and served it to the unsuspecting patron. If they don't complain the bar saved the money on a wasted pint, if they do complain the server looks like a hero for fixing the problem and providing a fresh, carbonated beer.

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lol that's just wrong.

badbrew said:

Last time I was at BJ's, the first pitcher was flatter than flat. The waitress blaimed it on sitting in the pitcher too long before serving. I wonder though because how is it going to stay cold that long?

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BJ's (wholesale club) sells pitchers of beer? Who knew...

AussieBrewerInColorado said:

lol that's just wrong.

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Agreed! I am dismayed at the number of bars I've seen do this, which suggest many others are just better at hiding this dirty little trick!