Spunding

[Thomas]

So im going to try my first spund(ed) beer this weekend, and need a few points on general protocol.

1. Brew 4.5 gal of beer, rack to fermenting keg.

2. Attach hose from fermenting keg gas out post, to the liquid in post of the second keg. Attach spunding valve to gas out post of second keg.

3. Allow fermentation to proceed at 6psi(?) for 2-3 days until hissing stops.

4. Dial spunding valve to 25-30 psi and allow to naturally carbonate for xxx long?

5. After carbonation is complete, attach fermenting keg to keggin system like normal and pour off a few pints until yeast and trub and cleared.

[Chris Craig]

That'll leave...what?  2 pints left?  

Seriously though, a 4 hour brew day for 4 gallons of beer?  I aim for 5.25 in the keg.

OT -- R.

[brew]

As I recall, usually crank up spunding to 25 or 30 psi when there's about .006 or .008 points left in the SG... Good to have a refractometer for that as its easier to get a drop or two out of one post, as opposed to a enough for a regular hydrometer to measure...

[Thomas]

That was another question, how to take samples for testing gravity. Do most people just bleed off the pressure and open the lid to take a sample? I may just guess when I think the ber is done and turn up the valve.

[Richard]

JQ and Fakr are the go-to-guys for this stuff, Thomas.

CC: that's a bit OT, kinda like everyone jumping on a Bud Clone thread and making jokes about piss

[brew]

I think you could open the keg to take samples, but it is one of the nice features of spunding is that O2 never hits the beer until you pour a glass. I invested in a refractometer so I could just take a quick couple of drops from the "out" post when spunding...

[JohnQ]

what brew said,
remove gas out connector,
tip keg about half way over so that the gas tube is covered on the inside by the wort
cover the post with a glass
press down on the poppet with a knife or pen or some such technical pointy thing.
collect some wort in the glass to measure
Refractometer works best, but you can get a few ounces out each time to measure with a hydrometer.

I usually crank the pressure when there is about 8-10 points left, but have found that it really only takes about 4 points to self carb.

I transfer to a serving keg, instead of serving off of the yeast cake.

To do that,
cold crash for a day or two
attach a picnic tap to the ferment keg and draw off a couple of cups, should be running clear by then
put co2 in serving keg and purge out the air.
set the pressure in the serving keg to a couple psi below the pressure in the ferment keg
attach a hose with black connectors on both ends to the out port of both kegs, the beer should start to flow, slowly as possible is good.
attach your co2 tank reg gas to the gas in on the ferment keg
attach your spunding valve to the gas connection on the ruserving keg and bleed off the excess pressure as the beer transfers.
Your natural carb won't be lost this way, and if transferred slowly, it will usually be very clear.
The speed of transfer can be increased by decreasing the head pressure in the serving keg, creating a larger differential, slowing it down the other way is more difficult, so if it gets going too fast and starts picking up trub, I usually disconnect, put a little more gas on the serving keg and resume, after you've done a few, it's like riding a bike.

JQ

[fakr]

Good luck Thomas!

A couple of pointers:

1.  Either fashion a shorter liquid dip tube out of copper tubing, or sacrifice the liquid dip tube in the keg for your overflow container.  Cut it to the same length as the gas dip tube.  I've learned this through experience.  it is not fun hearing and seeing backflow from the catcher into the fermentor, contaminating your fermenting beer.  No matter how careful you think you might be, if there's a possibility of it happening, it will eventually.  Cutting the dip tube so it's never submerged in liquid is the only sure way.  you might even "borrow" a gas dip tube temporarily from another keg you aren't using.

2.  either use the method John mentioned for collecting samples of wort, OR completely skip this step altogether.  I stopped checking my gravities when pressure fermenting until the brew is transferred to the serving keg.  I might be oversimplifying it a little, but if the spunding valve stops hissing, fermentation is done and there's nothing you can do about it anyway, so why bother checking the gravity when you can easily while transferring to the serving keg.

3.  Make super sure that the serving keg has been purged of CO2 and is FOR SURE below the pressure of the fermentor.  twice now I've read something like 14psi on the fermentor and set the serving keg to 12psi...then turned around, and used a picnic tap to pour off the first couple cups of yeast slurry from the fermentor, hooked up the transfer hose and heard the torrent of gas flow from the serving keg to the fermentor, completely disturbing he remaining yeast at the bottom of the fermentor.


pressure fermenting really isn't that complicated, but there are little suggestions like john and I mentioned that can help reduce the risk of producing murky beer.  Worst case you don't follow anything we said, you'll end up with great tasting, mostly naturally carbonated, murky beer.

[fakr]

how you making out with the spunding valve Thomas?

[Thomas]

Just got back from PEI today after judging the CWSF yesterday, there was some damn impressive science there.

Anyway, the keg was hissing nicely when I left monday morning, with the spunding valve dialed to about 7 psi. When I can home the valve was showing no pressure and making no hissing sound, so I assume fermentation is over. Tomorrow I am going to clean out my frige, and stick the keg in there to cold crash for a day before racking into a serving keg.

Its funny that you should mention your first point fakr. The whole brew day went very smooth, three hours start to finish and the CFC worked like a charm, although the beer didn't cool down quite as much as I wanted, only to 24C. I then attached my spunding valve to the second keg, containing a gallon of iodophor, and pressurised it to calibrate the vale to 7 psi before attaching the fermenting keg . . . . and immediately heard the iodophor being forced into the fermenting keg because it was not pressurized! So my beer may be a little more dilute and taste like iodine.

[Kyle]

I'd give the keg a good shake, wih the spunding valve disconnected, and then hook it back up, see if the yeast comes awake again... OR take a gravity sample.

[fakr]

yeah, it's a pain in the arse when you get back flow.  I'd seriously consider putting a gas tube in the liquid tube side so that doesn't happen again.

you could also shoot a good 7 psi of CO2 in your liquid in valve of your fermenter to rouse the yeast and pressurize the keg...crank your spumding valve up to 30 psi and leave it for 24 hours to see if it finishes up and self carbonates.

I've had the valve stop hissing completely with only 4psi on the gauge.  A good shake, or adding CO2 to the liquid in fitting to rouse the yeast brought it back to life and it self carbonated.

[JohnQ]

I'm a little concerned the valve fell to 0. It should never drop below that unless it was set to release more gas than the 6 psi. Getting that bang on can be a little tricky.
When you use it next time, shut it down so no gas is escaping and give it a good spray with soapy water to make sure there isn't a leak at one of the joints.

JQ

[fakr]

yeah, those spunding valves are very tricky to get to stay at a precice PSI.  I had to play with mine quite a bit to get it to 6psi.

[fakr]

I bought one of these regulators from princess auto:

http://www.princessauto.com/pal/product ... -Regulator

I added a larger, more precice gauge to it, and I hooked it up backwards (reverse air flow).  There is a small pressure relief valve built in that expels higher pressure on the output than what is dialed in at the regulator.  So, in essense, it functions like a spunding valve, and you can dial the pressure in more precicely.  The big adjustment knob even has a "push in and lock" feature to it so once you dial in the pressure, press the knob in and it's locks it there.

But with either spunding valve, setting the pressure is the same.  You hit the keg with 7-8psi, hook up the spunding valve and reduce the pressure until you can just start to hear a hiss.  leave it for 5 minutes and let it equalize in pressure. if it's still above the PSI you're aiming for, reduce the valve knob in very small increments and leave for 5 minutes at a time until the pressure has equalized to the pressure you want.