Zahm 1000: what do they mean by remove the false pressure???

[AlainB]

Hello guys.

We just got our zahm 1000. I've read the instruction but cannot figure what the company mean bey "remove the false pressure by opening the vent valve" By definition the pressure i read is the head pressure + hydrostatic pressure. SO .. this is not the reading i want righ? I want the reading of the pressure built by the release of gas in my beer. So, when i open the valve am i suppose to purge all that pressure? I think so, but on videos i've seen people just purge a little pressure out!

What am i getting wrong? Am i right with purging all the head pressure before opening the coil at the buttom and start shaking the device?

Thanks for you help!

Alain

[Dheeraj]

This false pressure is also known as Dynamic pressure because it arises from the motion of the fluid. We have to check the gas dissolved in the beer by shaking so that we can remove the dissolved gas from the beer to the head of the apparatus and then calculate with temp.

Without removing false pressure will give you a false-positive result.

We use Taprite to check the carbonation and they also recommend removing any type of false pressure.

Thanks

[MikeS]

My SOP (which I learned years ago and have been successfully implementing at a number of breweries) is:

-With the unit empty, open the top vent valve and exercise the plunger by moving it in and out a few times. It should be buttery smooth, if not *lightly* lubricate with the supplied Zahm grease. Then push the plunger back in and lock in place and close inlet and outlet valves.

-Hook the unit up securely the to the sample zwickel of the tank.

-Open the inlet and outlet valves of the Zahm, then open the zwickel. Beer will rush into the Zahm and come out the gooseneck piece on top.

-Once beer comes out, close the outlet. You will notice that the tiny sight glass on top is full of foamy beer: briefly open the top valve and let that foam out and then close it. Repeat once or twice until the beer in that sight glass is no longer foamy. (I think this is what they mean by "remove false pressure...")

-Close the bottom valve (top one should already be closed,) close the zwickel, then remove the Zahm. You now have a Zahm that is full of beer at the same pressure/temp as your bright tank.

-Turn the plunger anti-clockwise to release it from the cam lock, and shake it like the dickens. I have settled on 90 shakes - what's important is that you do it the same every time.

-After 90 shakes the plunger will (usually [unless the beer is drastically undercarbonated]) be distended and the pressure will have stabilized. Read the temp and pressure and check it against your chart to figure out the CO2 volumes.

Hope that helps.

Cheers - Mike

[AlainB]

Thank you guys
Thank Mike, you are right about what you wrote
I noticed that with the Zahm you better stick with the same process every time you make a test because if you don't you will surely get different final result in measuring.