altitude and Zahm CO2 volumes

[Rooh]

I am wondering if a correction for altitude needs to be made when using a Zahm and Nagel Volume meter to check carbonation. The Z&N chart does not note an altitude correction, but all the other volume charts I have seen have a correction of adding 1psi for every 2000ft above sea level.

Thanks, Rich

[Rooh]

shameless bump

Really? No one has experience with this? I have been carbing to 2.67 volumes according to the ZN chart for a couple of years, but sensually, my beers seem to have less carbonation than some of Sierra Nevada's beers, specifically the new Beer Camp Invitation. Any input would be appreciated. Thanks, Rich

[gbMusDvc]

It's a mechanical instrument that doesn't have any way of automatically adjusting the reading ... so yes, I would think you have to do the adjustment manually if you take the sample at high altitude (or low barometric pressure).

But so what if some (or one) of SN's beers are more fizzy? Just find the sweet spot for your own beers (Of course it's good to know the exact CO2vol anyway.)

[Rooh]

Fizzy beer

Yes, you are right. The sweet spot for my beers is most important, however, I do want them to dispense without problems wether they are served at sea level or 10000 ft. above. That is my main concern. Thanks for the reply, Rich

[TL Services]

I'm not massively familiar withe the Zahm as they're not too common on this side of the pond, but from my understanding the pressure measurement is a 'gauge' unit, ie. the pressure reading is zero before analysis is started.

That being so, you should not need to make any correction as that zero level will already take into account any differences in ambient pressure.

NB. I have just checked on Zahm's website - see link below:

http://www.zahmnagel.com/ServiceSupport/AltitudeDifferential/tabid/166/Default.aspx

Hope that helps!