Spunding for Dummies

[ChiknNutz]

I just received my shiny new Spundit valve and want to know how best to go about using it. Right or wrong, here's what I've done so far. I have a batch of stout I brewed on May 31 in my Kegmenter which can hold pressure (up to 35 psi before the relief valve lets go). I have hooked up a corny keg (for purging) from gas of fermenter to liquid of keg and have placed the Spundit on the gas of the corny keg. Upon advice of the maker to avoid a vacuum condition at the beginning of fermentation, I have the Spundit set to a slight pressure (right now at 5 psi) and all is right with the world with significant fermentation going on now. All of this is my newly fashioned FC holding at 67 degrees.

So I have read several spunding threads on here and it seems many don't spund until transferring to the keg or just slightly before. If so, does that mean I should NOT be spunding at all now and let it go at atmospheric until a couple days prior to fermentation ending? I don't employ a Tilt or other automated hydrometer, but have the standard style hydrometer, so have to take a sample for checking gravity. This part seems tricky to estimate, at least for me, since I am not a veteran brewer. I'd ultimately like to force carb and realize that it will not adequately carb at this temp and pressure, so is this initial low pressure doing anything for me? Any advice is appreciated.

 

[ChiknNutz]

Nobody?

 

[Gnomebrewer]

What you're doing at the moment has merit - it's purging the serving keg and keeping oxygen out of the fermenter, which are both good things. Fermenting at 5psi probably won't affect much. Fermenting under pressure suppresses esters, which is a good thing for clean beers and not so good for beers where you want yeast expression. But 5psi is quite low. I'd still avoid that much pressure for something like a hefeweizen until at least 2/3 attenuated. I personally don't ferment beers under pressure any more (but I used to).

My personal method is to add pressure/spund with about 6 to 10 points of gravity remaining, to about 5 to 10 psi, then transfer to serving keg (and increase spund pressure to full carbonation) as soon as it reaches that 5 to 10 psi mark. The benefit of transferring with some gravity left is that yeast will do a better job of using oxygen from the serving keg if they're still active and eating. No matter how well you purge the keg, there will be some small amount of O2 in there, so having active yeast is useful. It does leave more trub in the serving keg though.

 

[Gnomebrewer]

Also, why force carb if you have a spunding valve? That's one of the best things about spunding - no need to use bought CO2 to carbonate, and no introduced O2 from the commercial (impure) CO2.

 

[ChiknNutz]

Also, why force carb if you have a spunding valve? That's one of the best things about spunding - no need to use bought CO2 to carbonate, and no introduced O2 from the commercial (impure) CO2.

Could simply be my choice of words was improper. I intend to use the fermentation CO2 to the extent possible to both keg purge and carbonate. Isn't that still considered "forced carbonation" or is that what "spunding" really is? Could be I don't know the precise phraseology in this context.

 

[Gnomebrewer]

My understanding is that force carbonation is where bottled CO2 is pushed into the beer, thus carbonating it. Spunding is a form of natural carbonation.

 

[ChiknNutz]

Ya I just looked it up and it appears that the very definition of spunding (aka bunging) is as you say. Thanks for the clarification. I went and bled off a little to 3 psi. I may reduce it further, I dunno.

Here's one link that defines various forms of carbonation techniques.
http://trailhoncho.com/lounge/carbonation

 

[bmullins393]

This is something that I would like to try as well... please keep us updated on your progress, observations etc.
Thanks!

 

[lump42]

You can also use the fermentation co2 to push sanitizer out of the keg which will more effectively purge o2 out of the keg. Fermentor > gas post of keg 1, liquid post of keg 1 > liquid post of keg 2, gas post of keg 2 > container with inch of santizer. Last batch I purged the 7 empty kegs this way. I could of done more, but ran out of empty kegs.

 

[bmullins393]

You can also use the fermentation co2 to push sanitizer out of the keg which will more effectively purge o2 out of the keg. Fermentor > gas post of keg 1, liquid post of keg 1 > liquid post of keg 2, gas post of keg 2 > container with inch of santizer. Last batch I purged the 7 empty kegs this way. I could of done more, but ran out of empty kegs.

Hey this sounds pretty cool!
In this method, are you able to accomplish this and also, naturally carbonate with the fermentation Co2? Or do you use your co2 this way and force carbonate later?

 

[lump42]

Hey this sounds pretty cool!
In this method, are you able to accomplish this and also, naturally carbonate with the fermentation Co2? Or do you use your co2 this way and force carbonate later?

You could do either. My fermenter is not pressure capable. If I didn't have a 3-yo, I might have better timing, transfer at the tail end of fermentation, and add a spunding valve to naturally carbonate. My timing is terrible on that, so it depends on whether my kegarator is about empty or not. I force carbonate when it's empty and I want the keg ready quicker. If I can wait a few weeks, I'll add priming sugar to the keg and spund. If you naturally carbonate, you'll get more yeast pulled out in the first few pints unless you shorten the dip tube or use a floating diptube.

 

[bmullins393]

You could do either. My fermenter is not pressure capable. If I didn't have a 3-yo, I might have better timing, transfer at the tail end of fermentation, and add a spunding valve to naturally carbonate. My timing is terrible on that, so it depends on whether my kegarator is about empty or not. I force carbonate when it's empty and I want the keg ready quicker. If I can wait a few weeks, I'll add priming sugar to the keg and spund. If you naturally carbonate, you'll get more yeast pulled out in the first few pints unless you shorten the dip tube or use a floating diptube.

Love it! Makes perfect sense! I am going to give this try in a month or so!
Thanks so much!!!

 

[ChiknNutz]

This is something that I would like to try as well... please keep us updated on your progress, observations etc.
Thanks!

Here's my progress so far. I fermented for 5 days at about 3 psi and the plan was to spund after transferring to the keg. I transferred to the keg yesterday (June 5). At that time, there was still noticeable airlock bubbling, about 1/sec or so. Being this was my first time doing this process, I figured I could use the 3 psi to transfer from the kegmenter to the keg, just relieving the spunding valve. Perhaps I got impatient during the transfer but it seemed like I was not getting fluid transfer. I ended up futzing around with it all, took a sample and ended up relieving pressure all around. I then used the CO2 tank to complete the transfer. I assumed I'd be able to spund to naturally carbonate as it seemed like I had a bit of active fermentation still going on. Well it seems I don't. I applied the spunding valve and waited overnight to see if I still had active fermentation...none noted. So as of this morning, I removed the spunding valve and placed the keg in the kegerator (upright fridge). Based on the Force Carbonation Chart and my desire to hit 2.00 volumes of CO2 for the stout, I have the regulator set to about 6 psi (at 38 degrees) and plan to let it sit for about a week.

Point to note, when I took the sample, it was actually slightly below the target FG. Target was 1.022, measured was 1.019. Granted, I've only taking two samples (beginning and end), so I might be hasty on calling it done even though it indicates being below the target.

Overall, looks like I needed to spund earlier in order to capture active CO2 production. Again, being kinda new still, I figured I had done so early enough, but it appears fermentation was already complete within the 5 days, surprisingly. Or, I needed to actually wait longer than just overnight to see if active fermentation is going on. It may be too late now as it's in the fridge at 38 degrees.

 

[bmullins393]

Here's my progress so far. I fermented for 5 days at about 3 psi and the plan was to spund after transferring to the keg. I transferred to the keg yesterday (June 5). At that time, there was still noticeable airlock bubbling, about 1/sec or so. Being this was my first time doing this process, I figured I could use the 3 psi to transfer from the kegmenter to the keg, just relieving the spunding valve. Perhaps I got impatient during the transfer but it seemed like I was not getting fluid transfer. I ended up futzing around with it all, took a sample and ended up relieving pressure all around. I then used the CO2 tank to complete the transfer. I assumed I'd be able to spund to naturally carbonate as it seemed like I had a bit of active fermentation still going on. Well it seems I don't. I applied the spunding valve and waited overnight to see if I still had active fermentation...none noted. So as of this morning, I removed the spunding valve and placed the keg in the kegerator (upright fridge). Based on the Force Carbonation Chart and my desire to hit 2.00 volumes of CO2 for the stout, I have the regulator set to about 6 psi (at 38 degrees) and plan to let it sit for about a week.

Point to note, when I took the sample, it was actually slightly below the target FG. Target was 1.022, measured was 1.019. Granted, I've only taking two samples (beginning and end), so I might be hasty on calling it done even though it indicates being below the target.

Overall, looks like I needed to spund earlier in order to capture active CO2 production. Again, being kinda new still, I figured I had done so early enough, but it appears fermentation was already complete within the 5 days, surprisingly. Or, I needed to actually wait longer than just overnight to see if active fermentation is going on. It may be too late now as it's in the fridge at 38 degrees.

Thanks for the update, sorry it didn't work as hoped, but next time I am sure you will have better outcome. I've read some say they wait 2-3 days then spund, that way they still have some active fermentation going on grabbing some of that natural Co2.

I really like your set-up though, I am going to order a spunding valve and use a corny for fermentation/spunding.

Thanks!!!

 

[Bassman2003]

Sorry it did not work out. It IS complicated, but worth it. Your initial setup is the best approach. Using the fermentation CO2 output will scrub the serving keg of all oxygen (if you can, tilt the serving keg towards the liquid in post to try and get the trapped air to come out of the cornie lid rim area).

Remember, spunding is an exercise in fermentation control and yeast management. Active yeast are what makes your carbonation, so once you transfer to the serving keg, it needs to stay at fermentation temps so the yeast keep on working. Once fermentation is over, then move the now carbonated serving keg to the cold storage.

You can also use bottled CO2 to push the fermenting beer from the fermenter to the serving keg for spunding. That way you do not need to be as technical on pressures on each vessel. I would also agree to lower the pressure during fermentation as low as you can as to not effect yeast performance.

So a simple recap:
Start fermentation
Hook the serving keg up for purging with minimal pressure
Try to transfer the fermenting beer with 7-4 gravity points remaining to Final Gravity
Keep the serving keg with the transferred beer in it at the same fermentation temps until you are finished fermenting and are fully carbonated
Move the serving keg to cold storage.

Another tip on when you hook up a spunded keg to your bottled CO2 serving setup. I close the regulator valve, grab the quick disconnect and press the button inside to relieve the pressure out of the line. Then lower the pressure of the regulator to BELOW your target PSI. Hook up the keg and open the regulator valve. This will cause the regulator to jump and read the pressure coming in from the keg. You can then slowly raise the pressure of the regulator to match the keg pressure for serving.

Basically we gauged the pressure of the spunded keg and matched the serving system to meet it. The whole point of spunding is to limit the use of bottled CO2 as the bottled CO2 does contain oxygen which stales your beer over time.

For spunding, a Tilt is your friend!!! Good luck with the next one.

 

[ChiknNutz]

I initially kept the keg a little above fermentation temp...FC was at 67, basement is now about 72 and I kept it in the ambient basement temp overnight. Again, I may be been premature in putting it in the fridge this morning, but I figured that 10 or so hours later should have been enough to witness further fermentation via the spunding valve airlock.

I have thought about a Tilt or similar setup, just trying to curb the spending a bit for now. It would definitely help for this setup since I cannot see anything aside from the airlock on the spunding valve. Thanks for all the useful tips.

Timing is of the essence in this particular process.

 

[ChiknNutz]

Should I go ahead and keep the keg in the fridge until carbonated, or is there some benefit in returning it to ambient air for a few days? I kinda think the ship has sailed for the latter, but wanted to ask nonetheless.

 

[Steven Barrett]

Spunders, how are you taking numerous hydrometer samples without exposing the beer to oxygen?

 

[EDF713]

Spunders, how are you taking numerous hydrometer samples without exposing the beer to oxygen?

I've tried spunding a few times, maybe not an expert but I've done it enough to get the hang of it. I've used a Tilt and after I started fermenting in kegs I used a serving line for a hydrometer sample. The last couple of times I just waited for activity to slow then put on the valve and set it. The beauty of a spunding valve is you don't need to know exactly when to do it as long as the beer isn't finished fermenting. If it's too early then the spunding valve will release the excess pressure. If it's too late then you can force carb the rest.

 

[Steven Barrett]

I thought the typical process is ferment in a vessel and once gravity is X points from finishing based on fast ferment test, transfer to keg or bottles. In a keg with a spunding valve there’s room for error but certainly not in bottles.

I would see it being a challenge to ferment in a glass carboy and take samples without introducing oxygen.

 

[ChiknNutz]

Spunders, how are you taking numerous hydrometer samples without exposing the beer to oxygen?

If you spund, you must be using a vessel capable of holding pressure. In my case, I am using a kegmenter that has ball lock QDs. From there I attach a liquid line with a picnic tap to take a sample. I need to start making slightly larger batches, like 5.5 or maybe 6 gallons as I hate to end up with less than 5 gallons which happens if you take several samples. Have only done this once so far, so very far from an expert on the subject.

Ideally, you'd use a Tilt or iSpindel so you can take continuous readings and not waste anything, but then it's just more money and another thing to futz with.

 

[ChiknNutz]

Sorry it did not work out. It IS complicated, but worth it. Your initial setup is the best approach. Using the fermentation CO2 output will scrub the serving keg of all oxygen (if you can, tilt the serving keg towards the liquid in post to try and get the trapped air to come out of the cornie lid rim area).

Remember, spunding is an exercise in fermentation control and yeast management. Active yeast are what makes your carbonation, so once you transfer to the serving keg, it needs to stay at fermentation temps so the yeast keep on working. Once fermentation is over, then move the now carbonated serving keg to the cold storage.

You can also use bottled CO2 to push the fermenting beer from the fermenter to the serving keg for spunding. That way you do not need to be as technical on pressures on each vessel. I would also agree to lower the pressure during fermentation as low as you can as to not effect yeast performance.

So a simple recap:
Start fermentation
Hook the serving keg up for purging with minimal pressure
Try to transfer the fermenting beer with 7-4 gravity points remaining to Final Gravity
Keep the serving keg with the transferred beer in it at the same fermentation temps until you are finished fermenting and are fully carbonated
Move the serving keg to cold storage.

Another tip on when you hook up a spunded keg to your bottled CO2 serving setup. I close the regulator valve, grab the quick disconnect and press the button inside to relieve the pressure out of the line. Then lower the pressure of the regulator to BELOW your target PSI. Hook up the keg and open the regulator valve. This will cause the regulator to jump and read the pressure coming in from the keg. You can then slowly raise the pressure of the regulator to match the keg pressure for serving.

Basically we gauged the pressure of the spunded keg and matched the serving system to meet it. The whole point of spunding is to limit the use of bottled CO2 as the bottled CO2 does contain oxygen which stales your beer over time.

For spunding, a Tilt is your friend!!! Good luck with the next one.

Here's another approach I just thought of, devoid of a Tilt or iSpindel.

1. Connect fermenter to serving keg and attach spunding valve to keg, spund at very low pressure (like 1-3 psi).
2. Spund until serving keg is purged (maybe 2 days?), then disconnect gas line between fermenter and keg.
3. Move spunding valve to fermenter until completion of fermentation. At about day 3 or 4, crank up valve to desired carbonation pressure and allow for natural carbonation.
4. Once fermentation is complete (or it's been in there as long as you want), transfer to serving keg, using the excess pressure in the fermenter.

I guess all this really does is help if you to not miss the tail end of fermentation, which is what it looks like happened to me this time.

 

[Steven Barrett]

Wouldn’t it make more sense to transfer the beer to the serving keg once you’ve purged it? Then attach spunding valve to serving keg at desired pressure?

 

[ChiknNutz]

Wouldn’t it make more sense to transfer the beer to the serving keg once you’ve purged it? Then attach spunding valve to serving keg at desired pressure?

I think ideally yes. What happened to me this time is I waited too long, only 5 days, to transfer to the keg. I was thinking this approach would allow for a bit more oops-factor if you don't hit it right with knowing the right point in fermentation to start spunding.

 

[Bassman2003]

I do not think your new approach takes advantage of the fermenting yeast. The key is to transfer the fermenting beer to its serving keg while it still has extract remaining. That way you have the best chance to scavenge all of the oxygen for packaging. Ferment & purge at the same time, transfer with a little extract remaining, then spund to carbonate the beer. Simple if you have a good way to tell the gravity of the beer.

 

[Steven Barrett]

If it wasn’t stated before, although a spunding valve permits you to ferment under pressure, I don’t think that’s it’s original intent - at least not in the usage of the word spunding. Although you could use your spunding valve to ferment under pressure, I think the traditional way is to ferment at atmospheric then once you are a few points before reaching terminal gravity, close the vessel to capture the remaining CO2 generated by your fermentation into solution. In your case, attach a spunding valve and in case you overshot and created more CO2 than desired, the spunding will bleed that off.

 

[ChiknNutz]

Round 2. Made my first BIAB batch last Sunday, an Orange SMaSH Ale. My plan was to transfer from fermenter to keg after 3 days this time so I would have a better chance of active fermentation. Went ahead and did that last night. Also took a hydrometer reading, came in at 1.025 and my planned FG is 1.018 so I think I am in good shape for spunding.

Relocated spunding valve from fermenter to keg and increased the pressure to around 25-30 psi (it's not exact until it reaches pressure, though it is fairly accurate in psi per revolution). After a few hours, noticed it had already increased to about 5 psi. This morning it was about 28 psi, which is actually just about right for 2.4 volumes at 72 degrees. I bled some off as I thought my target was 25 psi, but went into the calc again afterwards and think I want to shoot for 2.4 volumes, so cranked up again, shooting for around 28 psi.

Overall I do like this process. One issue I've discovered is though I intentionally allow a low psi during initial fermentation (around 5 psi max) so that I can use that pressure for the transfer, I am finding that is inadequate and still need to supplement with bottled CO2. I was not so impatient this time and let the transfer go for a few hours using the original pressure, but it seemed to stall. I then hooked up the CO2 and let it go for another hour or so. That completed the transfer but I thought part of the goal was to use the CO2 for the transfer. I could of course increase the pressure during fermentation, but it seems the jury is out on whether or not it's a good idea to ferment under pressure.

 

[Steven Barrett]

I don’t think many people are fermenting under pressure in order to use that pressure to transfer to kegs. It’s my understanding they are doing so because it results in less expression of phenolics and thus a cleaner tasting beer.

If one of your objectives is closed transfers, there are several users here that use gravity to transfer from fermenter to purged keg in a closed environment which alleviates the need to pressurize your fermenter or supply CO2 as the driving force, so if you want to continue to ferment under pressure but need supplemental force, you can use gravity instead of CO2. Also using larger diameter and shorter tubing will reduce your friction losses, so your fermenter pressure will be able to do more work to push the beer into the keg.

 

[ChiknNutz]

Due to the design of the kegmenter, you must use some sort of a pressurized transfer. I haven't tried it yet as I've only used for two batches thus far, but I imagine if I were to elevate that above the keg, it would probably work better. The small pressure delta would get it going and then should continue on it's own if elevated high enough to overcome frictional losses. It's not objectionable to use the bottled CO2, just looking at ways to improve the process.

 

[VikeMan]

It’s my understanding they are doing so because it results in less expression of phenolics and thus a cleaner tasting beer.

I know fermenting under pressure can suppress esters, but I have never found any data to indicate it suppresses phenols. Do you (or anyone) know of any?

 

[Vale71]

If you were to spund the beer to 15 PSI you'd have to leave exactly half of the fermenter volume empty to have enough pressure to transfer the whole volume of beer without supplemental CO2. If you did you would then run into the issue of transferring somewhat carbed beer at an ever dwindling pressure which might cause serious foaming issues. I'm afraid you'll have to either try your hand at gravity transfer or accept the need for bottled CO2 as propellant.

 

[Vale71]

I know fermenting under pressure can suppress esters, but I have never found any data to indicate it suppresses phenols. Do you (or anyone) know of any?

Pressure fermentation also suppresses higher alcohols of which phenols are a subgroup so I'd expect pressure to suppress their expression as well. Anyway I'm not sure how much of an effect it will have compared to the usual parameters such as yeast strain and level of precursor in wort.

 

[VikeMan]

Pressure fermentation also suppresses higher alcohols of which phenols are a subgroup so I'd expect pressure to suppress their expression as well.

I know that some higher alcohols are phenol derived, but since when are phenols a subgroup of alcohols? i.e. AFAIK chemist define alcohols and phenols separately.

 

[Vale71]

You're right, my bad.

 

[ChiknNutz]

Pretty happy with how this is going so far.

 

[Bassman2003]

Cool. Glad to hear of your progress. The procedure is pretty easy, just finding the right time is what takes some effort.

 

[Yesfan]

Subscribed.


I have a 10G batch of pale ale I'm kegging later tonight. I'm new to spunding too, but this batch I attached the valve to my conical after fermentation started to slow down. Has been holding at 10psi the past couple of days.

 

[RePete]

Following. I was going to buy a Kegmenter and haven’t yet. Interested in you results.

 

[Steven Barrett]

Seems like a lot of you are using your spindijg valve to carbonate in the fermenter and then transfer the carbonated beer to the keg. Can anyone explain why? I thought the typical process was to ferment under atmospheric pressure, then transfer the beer with a few gravity points to go into the keg then close the keg and the spunding valve is there to bleed off any excess pressure in case you transferred it with too many gravity points remaining.

 

[bmullins393]

Round 2. Made my first BIAB batch last Sunday, an Orange SMaSH Ale. My plan was to transfer from fermenter to keg after 3 days this time so I would have a better chance of active fermentation. Went ahead and did that last night. Also took a hydrometer reading, came in at 1.025 and my planned FG is 1.018 so I think I am in good shape for spunding.

Relocated spunding valve from fermenter to keg and increased the pressure to around 25-30 psi (it's not exact until it reaches pressure, though it is fairly accurate in psi per revolution). After a few hours, noticed it had already increased to about 5 psi. This morning it was about 28 psi, which is actually just about right for 2.4 volumes at 72 degrees. I bled some off as I thought my target was 25 psi, but went into the calc again afterwards and think I want to shoot for 2.4 volumes, so cranked up again, shooting for around 28 psi.

Overall I do like this process. One issue I've discovered is though I intentionally allow a low psi during initial fermentation (around 5 psi max) so that I can use that pressure for the transfer, I am finding that is inadequate and still need to supplement with bottled CO2. I was not so impatient this time and let the transfer go for a few hours using the original pressure, but it seemed to stall. I then hooked up the CO2 and let it go for another hour or so. That completed the transfer but I thought part of the goal was to use the CO2 for the transfer. I could of course increase the pressure during fermentation, but it seems the jury is out on whether or not it's a good idea to ferment under pressure.

Thanks for sharing your experience! Truly helpful!