.75-1.3 co2 - say what?

[backflip]

Doing research ahead of my draught system arriving, and I'm a bit confoosed at what I'm seeing as far as recommended volumes.

For light scottish ales and british pale, I'm seeing a recommended co2 volume of .75-1.3. But when I look at the tables to see how to achieve that low level, it doesn't even look possible! One calculator I used said I'd have to set it at less than .1 PSI! What am I missing here? I'm pretty sure that I'm misunderstanding the material.

 

[billl]

Eh - don't get too caught up in the numbers. They seem to really overstate the "to style" ranges. 1.3 volumes would be considered flat beer in pretty much any bar in the US. Everyone tastes things differently, but for my money, I wouldn't aim for anything lower than 2 volumes for engish stles and 2.4 for most american ales. Part of the joy of having your own kegs is that you can dial in the level you like, so experiment away.

 

[hunter_le five]

I think you mean 1psi, not .1

.75-1.3 seems kind of low to me, I would think 1.5-2.2 would be more reasonable.

And the PSI you use is not merely dependent on your desired carbonation level, but also your temperature.

http://www.kegerators.com/carbonation-table.php

For example, to achieve 1.5 volumes of CO2 at 50 degrees, you would apply 5psi (see chart in above link).

 

[dyqik]

English and Scottish ales are usually served in the UK from casks, without CO2, not from kegs. The cask is at a minimum of 55F, and open to the atmosphere (or maybe a cask breather, which backfills the cask with CO2 at atmospheric pressure), and beer is pulled out by a handpump or gravity. However, 0.75 vols is flat, even for Real Ale.

In bottles, you'd prime those beers for about 1.5 vols. For a keg system, just set the CO2 just high enough to push the beer out of the tap at a reasonable speed, and make sure the keg isn't too cold.

 

[backflip]

I'm an analyst by trade, so I can't help looking at the numbers 8)

I'm going to aim for 1.8 then, based on these insights. Makes sense that the low recommendations stem from the casking.

Related question though: what about the resistance from the tubing? I read somewhere that I'll need to have at least 2 PSI per foot of tubing, so at 5' that would mean 10 PSI. How does that jive if I want 1.82 at 50F, which would be 9 PSI according to the chart? Does that just mean I should set at 9 and the pour might be a little slower than optimum?

 

[dyqik]

Those pressure drops are for a typical serving rate - exceeding the pressure drop will give you a slower rate. 1 psi here or there isn't a big deal for the flow rate from a 9psi keg.

The 2-3 psi/foot is for 3/16" line. For 1/4" line it'd be nearer 0.5-0.8 psi/foot. So if you want to keep the carbonation low, you could switch to 1/4" line - you just need a different tailpiece and flare nut for that line to those for 3/16" line.

For highly carbed beers like hefeweizen or saison, you can go to 10ft of 3/16" line to allow a higher serving pressure.

See Keg Line Balancing on beersmith.com and the calculator here.

 

[day_trippr]

Ok, so the BeerSmith line length calculator makes all the same classic errors that manifest nearly every other calculator out there. That's a given.

But did you actually look at the Calczilla line length calculator? Holy crap, that thing is utterly broken!
Where 98% of the calculators out there will recommend a 5 foot line for the typical application, Calczilla recommends 2.3' of 3/16' ID beer line! Wow.

Listen, y'all can screw around with all those ridiculous tools and come back to start the inevitable "Help! My pours are all foam!" threads which plague this forum.
Or...you can go straight to the one beer line length calculator that actually works...

Cheers!

 

[billl]

The generic advice is "use 10 ft of line". Yes, you might well be able to get away with less for some/many of your beers depending on the actual pressures and specifics of your system. The downside to being too long is a slightly slower pour. The downside to being too short is too much foam. I understand why bars would be concerned about shaving 3 seconds off a pour, but I've got that kinda time to spare at might house.

 

[dyqik]

Ok, so the BeerSmith line length calculator makes all the same classic errors that manifest nearly every other calculator out there. That's a given.

But did you actually look at the Calczilla line length calculator? Holy crap, that thing is utterly broken!
Where 98% of the calculators out there will recommend a 5 foot line for the typical application, Calczilla recommends 2.3' of 3/16' ID beer line! Wow.

Listen, y'all can screw around with all those ridiculous tools and come back to start the inevitable "Help! My pours are all foam!" threads which plague this forum.
Or...you can go straight to the one beer line length calculator that actually works...

Cheers!

That's the one I couldn't find yesterday.

However, if you allow a small variation in serving rate - e.g. between 8 and 12 seconds per pint - it gives the same answers as the other calculators for typical cases. 5ft of 3/16" line is fine for 8psi serving pressure at 34-36F for APAs (2.3 vols and 9 seconds per pint - actually slower because of losses in the tap and fittings), and 10ft of 3/16" line is fine for 18psi serving pressure at 34-36F for hefeweizen/saison (3.4 vols and 8 seconds per pint before additional losses). It does suggest that the serving pressure for an English ale with 2 ft of 1/4" line would be about 1.3 psi, which gives a carb level around 1.2 vols at 55F (you shouldn't be going much lower in temperature than that) which would be hard to control on a standard regulator.

All this is with the taps near the top of the kegs - e.g. in a keezer with taps on the collar or a fridge with taps on the door.