When is spunding worth trying?

[Turfgrass]

I'm interested in the idea of spunding to carbonate in a keg after first fermenting with a carboy, but when is using a spunding valve used most of the time? Currently trying to learn the reasons as to why and how to spund. Do you transfer to keg/spund with a couple points above FG or do you use CBC yeast to complete and scrub O2. Thoughts?

 

[cactusgarrett]

Without getting into a debate on the type of carbonation, some people (including myself) find natural carbonation different than/preferred over forced carbonation.

In this case, you'd transfer the contents of the carboy over to a keg then just seal her up. Ideally, you'd know the expected FG (via experience with this recipe or a fast ferment test), so you know what gravity would be "too late" to make the transfer, and thus undercarbonating it (naturally). You'd want to err on the side of making the transfer with higher gravity than your target, as that's what the spunding valve does - acts as a pressure relief valve when the pressure gets above your target.

Adding new yeast isn't necessary, even if you miss your window to transfer (and run the risk of undercarbing), because there's still plenty of yeast in solution. In that case you'd either add sugar (if you were looking to naturally carbonate - like one big bottle), or you'd force carb with CO2 the rest of the way. You shouldn't, however, assume that the remaining fermentation in the keg is going to scrub all oxygen picked up in the transfer, so you should still practice good anti-oxidation measures (ie. purging the keg with CO2 before transferring).

 

[Spartan1979]

Without getting into a debate on the type of carbonation, some people (including myself) find natural carbonation different than/preferred over forced carbonation.

In this case, you'd transfer the contents of the carboy over to a keg then just seal her up. Ideally, you'd know the expected FG (via experience with this recipe or a fast ferment test), so you know what gravity would be "too late" to make the transfer, and thus undercarbonating it (naturally). You'd want to err on the side of making the transfer with higher gravity than your target, as that's what the spunding valve does - acts as a pressure relief valve when the pressure gets above your target.

Adding new yeast isn't necessary, even if you miss your window to transfer (and run the risk of undercarbing), because there's still plenty of yeast in solution. In that case you'd either add sugar (if you were looking to naturally carbonate - like one big bottle), or you'd force carb with CO2 the rest of the way. You shouldn't, however, assume that the remaining fermentation in the keg is going to scrub all oxygen picked up in the transfer, so you should still practice good anti-oxidation measures (ie. purging the keg with CO2 before transferring).

If you're spunding in a keg, I still assume that you are still using CO2 from a tank to provide serving pressure. Over time, wouldn't a lot of that natural carbonation be replaced the CO2 from the tank?

 

[bkboiler]

If you're spunding in a keg, I still assume that you are still using CO2 from a tank to provide serving pressure. Over time, wouldn't a lot of that natural carbonation be replaced the CO2 from the tank?

if you spund to 2 volumes...cold crash, then serve at 15psi, it'd take until the end of the keg to be 50:50 ratio of "natural" CO2 to dispense gas

I started spunding to avoid dry airlocks...suckback, cold crash issues and also CO2 is darned expensive around here...

Further...it saves time on waiting for the beer to carb! And goes hand in hand with pressure transfers which IMHO are easier than siphoning.

 

[Jim R]

I think you are asking the wrong question. The question should probably be - When is pressure fermentation worth trying? A spunding valve is just a piece of equipment to help and allow pressure fermentation. I would instead start to research pressure fermentation.

I also don't think the answer to this question about when to consider pressure fermentation is to allow for natural carbonation. For me, that is a nice side benefit but not the real purpose or goal of pressure fermentation.

 

[Turfgrass]

if you spund to 2 volumes...cold crash, then serve at 15psi, it'd take until the end of the keg to be 50:50 ratio of "natural" CO2 to dispense gas

I started spunding to avoid dry airlocks...suckback, cold crash issues and also CO2 is darned expensive around here...

Further...it saves time on waiting for the beer to carb! And goes hand in hand with pressure transfers which IMHO are easier than siphoning.

At what point do you start the spunding valve process?

 

[Turfgrass]

I think you are asking the wrong question. The question should probably be - When is pressure fermentation worth trying? A spunding valve is just a piece of equipment to help and allow pressure fermentation. I would instead start to research pressure fermentation.

I also don't think the answer to this question about when to consider pressure fermentation is to allow for natural carbonation. For me, that is a nice side benefit but not the real purpose or goal of pressure fermentation.

Thank you for the suggestion and I will research pressure fermentation.

 

[Dr_Jeff]

At what point do you start the spunding valve process?

For me, I put the spunding valve on when I close the fermenter, immediately after pitching the yeast. Initially set low, then turn it up every few days, until it gets to the desired setting, it stays there until I transfer the beer. I usually cold crash, close to 33-34 and it stays there for several days, and I'll transfer either fully carbonated or mostly carbonated beer into pre-purged kegs.

 

[cactusgarrett]

At what point do you start the spunding valve process?

You make the transfer at a time when there's more gravity than would otherwise be needed to carbonate your keg, but that depends on the expected FG of your batch, so obviously that would vary. For example, if I expected my pilsner to go from 1.055 to 1.013, I'd probably start spunding around 1.023 or so; enough to overshoot the desired psi, but not enough where the majority of the fermentation is done under pressure.

 

[El Duderino]

At what point do you start the spunding valve process?

I attach mine to my fermenter after High Krausen, and set to 15psi. the beer is pretty well carbonated after cold crash when I transfer to a keg

 

[VikeMan]

I attach mine to my fermenter after High Krausen, and set to 15psi. the beer is pretty well carbonated after cold crash when I transfer to a keg

~1.7 volumes, assuming you were spunding at ~ 68F at the end. You may already know this, but FWIW, you can use the keg force carbonation charts/calculators to figure out what level of CO2 you'll get from spunding at "X" pressure and "Y" temperature.

 

[kmarkstevens]

Just in case you didn't realize this, you don't NEED a spunding valve (it's embarrassing how long it took me to figure this out). You can spund (a bit randomly) by adding ~1/2 cup of plain white sugar (or corn sugar or DME) to the keg and let that ferment and build up pressure for a few days or a week. The yeast revive, process teh sugar, produce alcohol and CO2 that carbonates the keg.

The spunding valve merely allows you to accurately spund to the desired carbonation level. David Heath Homebrew has a couple of video tutorials, including this one: (11) Spundit V2 vs Blowtie Full Comparison for Homebrewers - YouTube

 

[VikeMan]

Just in case you didn't realize this, you don't NEED a spunding valve (it's embarrassing how long it took me to figure this out). You can spund (a bit randomly) by adding ~1/2 cup of plain white sugar (or corn sugar or DME) to the keg and let that ferment and build up pressure for a few days or a week. The yeast revive, process teh sugar, produce alcohol and CO2 that carbonates the keg.

The spunding valve merely allows you to accurately spund to the desired carbonation level.

Okay, there are two different methods here, and only one of them is spunding.

Adding sugar to finished beer and allowing it to carbonate in a sealed keg isn't spunding. It's the same thing as bottle conditioning (but in one big bottle), and it can be done as accurately as you want. The amount of sugar needed for a given level of CO2 is easily computed.

Spunding to carbonate, on the other hand, is when you allow the primary fermentation to finish with a pressure relief valve set to the pressure (at a given temperature) that will result in the CO2 level you want, because any excess pressure will be released.

Neither is inherently more accurate than the other.

 

[verboten]

When is it worth trying? When you have the money to buy or build a valve.

I’ll never go back.

 

[kmarkstevens]

Okay, there are two different methods here, and only one of them is spunding.

Fair point and accurate too!

My point is that there is no need to go buy a spunding valve if you want to test out what the spunding result will be, or something equivalent to the spunding result. Some folks (me) got hung up on getting a crappy spunding valve before trying keg conditioning. Sure, it's not literally spunding, but unless I'm missing something the result will be more or less the same.

In my humble experience, I have found either spunding or keg conditioning has a sweet spot of about a gallon of well conditioned perfectly carbonated beer. Then need the CO2 to push out the rest or really get into the rabbit hole.

 

[VikeMan]

Sure, it's not literally spunding, but unless I'm missing something the result will be more or less the same.

A couple of differences.... Carbonating with added sugar increases ABV (as does bottle conditioning). Spunding doesn't. And the open transfer to the keg (or opening to add sugar) increases O2 uptake. This is a major reason some people (especially the LODO folks) spund.

In my humble experience, I have found either spunding or keg conditioning has a sweet spot of about a gallon of well conditioned perfectly carbonated beer.

How is "a gallon" (in particular) significant?

Then need the CO2 to push out the rest or really get into the rabbit hole.

Yes, you need additional CO2 to push the beer out of the keg to serve, regardless of how you carbonated it. If you don't, you overcarbonated it.

 

[Golddiggie]

Fair point and accurate too!

My point is that there is no need to go buy a spunding valve if you want to test out what the spunding result will be, or something equivalent to the spunding result. Some folks (me) got hung up on getting a crappy spunding valve before trying keg conditioning. Sure, it's not literally spunding, but unless I'm missing something the result will be more or less the same.

In my humble experience, I have found either spunding or keg conditioning has a sweet spot of about a gallon of well conditioned perfectly carbonated beer. Then need the CO2 to push out the rest or really get into the rabbit hole.

I've tried those DIY spunding valve setups before. Never as good as the Blowtie was when I used one. I still have both versions on hand from when I was using kegmenters (sanke kegs). Now I'm using the SS Brew Tech spunding valves that are beyond excellent if you have a conical fermenter (they connect to a 1-1/2" TC fitting). I have one on each of my conicals now. I also have the gas manifold which includes a gauge, gas post and PRV (15psi which is the listed working pressure limit for the conical). The SS Brew Tech spunding valve is a one-way valve that you add Starsan to. Fill to above the line of holes in the unit and you're done. IMO, ANY spunding valve that doesn't send the CO2 through an airlock (or otherwise creates a break between the gas flow and inside the fermenter) is not worth using.

I use the spunding valve to set the fermenting pressure level I want for the recipe. There's other benefits besides having a batch PARTIALLY carbonated when it finishes. I also leave the spunding valve in place for when I carbonate in conical, to prevent any issues. It's worked great for the batches I've used the method with. I do chill the finished beer to a set level (about 50F) and let the yeast settle fully before I dump the yeast and then start carbonating. I'm using a carbonation stone to do that (dropping the beer temp to about 35F for that part). A few days later, the batch is ready for keg and can.

I would have though people who keg would realize that as CO2 is used up to push the beer out, you need to add more in to maintain pressure levels. It's not brain science after all. If you thought you could get away without adding CO2 into a keg and push the entire keg of beer out, while maintaining the carbonation level, well... Not going there.

 

[VikeMan]

The SS Brew Tech spunding valve is a one-way valve that you add Starsan to. Fill to above the line of holes in the unit and you're done. IMO, ANY spunding valve that doesn't send the CO2 through an airlock (or otherwise creates a break between the gas flow and inside the fermenter) is not worth using.

IMO a sanitizer cup on a spunding valve is a solution in search of a problem. I've never had an issue from not using one, and it doesn't seem to present enough of a risk for the big boys to use them that way. The only time I've seen a commercial brewer with that style of valve (i.e. with a sanitizer reservoir), they weren't putting any sanitizer in it. But I suppose I would agree that it takes a very close to zero risk even closer to zero.

 

[Craiginthecorn]

I think you are asking the wrong question. The question should probably be - When is pressure fermentation worth trying? A spunding valve is just a piece of equipment to help and allow pressure fermentation. I would instead start to research pressure fermentation.

I also don't think the answer to this question about when to consider pressure fermentation is to allow for natural carbonation. For me, that is a nice side benefit but not the real purpose or goal of pressure fermentation.

Traditionally-speaking, I believe you have this reversed. A spunding valve was used solely to carbonate, simplifying the process of kräusening, which usually involved adding fresh wort ("kräusen") to fully-fermented beer. Instead, the spunding valve is added late in fermentation to capture a precise amount of dissolved CO2. This is the process followed by Jack’s Abbey, which makes non-traditional lagers.

Pressure fermentation is a newish idea which attempts to emulate the naturally occurring pressure at the bottom of gigantic commercial cylindroconical fermenters. The claimed benefit is being able to suppress ester formation, allowing you to produce a lager-like beer at warmer temperatures than normal, which also means the fermentation is complete much sooner.

Chris White and John Blichmann did an experiment which was discussed on this episode of BeerSmith. Their rather simple experiment produced generally positive results. Brülosophy recently did a detailed exBeeriment. Their results appear to at least temper the claims of the proponents of pressure fermentation. Testers could readily distinguish the pressure fermented sample from the traditionally fermented samples. Also, lab results showed higher levels of esters in the spunded beer. This is not really surprising, given that the pressure-fermented beer was fermented at ale temperatures. Interestingly, the majority of testers preferred the pressure fermented beer.

 

[Smudgey]

The benefit for me is when crash cooling under pressure it reduces the risk of O2 suck-back. I've had this happen in brand new ways too many times in my short brewing-life to mention without being embarrased about it. It became worth it for me after watching my beer (and mood) darken, again. Following an attempt to finish the keg late one night (before it got worse) I ordered a blowtie2 and some push-fits and a whole bunch of 'cheap' items /fittings that added up to a big enjoyable beered-up splurge. The next bad brew I clicked 'add to cart' on the fermzilla. I've never made the exact same mistake twice, but the problem for me is I've just found so many new ways to screw this bit up.

I've only splunded the last few brews but its nice not risking the CO2 in my gas bottle to leaks crashing under pressure, seals on mylar balloons leaking, surprise cold crashes by wrong fermention profile setups (actually more than once) etc... Splunding from a fermzilla saved a recent brew from a really inventive surprise cold crash: I shorted the AT1000 cooling relay by drowning it in starsan after mixing up the in-out posts while daisy-chain purging kegs.

Not using bought gas for more than topping up/serving feels nice too. Right now I'm day six of trying to carb a stout using CO2 vented at 15psi from an ESB currently in the fermenter. I ran a line from the fermenter from a push-fit Tee (placed before the valve) into the fridge and onto its carb stone. I chose this rather than spunding from the stout keg - just thoughts about all the volumes of CO2 passing through stripping / adding flavor. When i add a picnic tap to sample it technically I'll be serving a few using spunding pressure also.

 

[cactusgarrett]

(My OCD is kicking in and it's gonna drive me nuts if I don't say it )
It's SPUNDing. No "L".

 

[Bassman2003]

I think you are asking the wrong question. The question should probably be - When is pressure fermentation worth trying? A spunding valve is just a piece of equipment to help and allow pressure fermentation. I would instead start to research pressure fermentation.

I also don't think the answer to this question about when to consider pressure fermentation is to allow for natural carbonation. For me, that is a nice side benefit but not the real purpose or goal of pressure fermentation.

I agree with Craig, spunding and pressure fermentation are two separate practices. The OP is asking about post-fermentation practice, or at least end of fermentation practice. That is spunding which gets carbonation from the yeast activity in your serving vessel.

The toughest part of spunding is knowing when to release the kraken so to speak. I wound up buying a tilt which helps me know when I am 5-6 points away from the target FG. When I dry hop, I will let the beer finish out, add some sugar and CBC yeast, wait for activity (10- 30 min) then spund. The dry hops are added with about 10 gravity points remaining.

I am glad to see more posts about this technique as I have enjoyed it sing I took the plunge.

 

[Smudgey]

It's SPUNDing

Spluttering, splurging... and spunding. Big thanks to your OCD!

 

[kmarkstevens]

I believe the OP w

I'm interested in the idea of spunding to carbonate in a keg after first fermenting with a carboy

The easiest way to dip your toe in the water is to pressure carbonate. Fill your keg from the carboy, dump in 1/2 cup sugar, and wait a week. Pull the pressure release valve, and it should obviously have some CO2 under pressure. Try the beer and check if you can see and/or taste a difference, or if you like the taste.

Your keg may be overcarbonated after it is chilled. Either drink frothy beer or bleed off the pressure release valve. If it's undercarbonated, hook up your CO2 tank and push it out. I find that there is maybe a gallon that seems to be perfectly carbonated in there, and when the sweet spot is getting under carbed, then turn on the CO2. When using an actual dialed in spunding value, your beer will be carbonated at the level you desire. That said, at some point it will become under carbed and you'll have to turn on the CO2.

If you like the resulting bubbles, taste, mouth feel, etc, then I would look at the Blowtie or something similar and start doing actual spunding. Anyhoo, it's a really easy test to see if spunding might be for you.

 

[VikeMan]

The easiest way to dip your toe in the water is to pressure carbonate. Fill your keg from the carboy, dump in 1/2 cup sugar, and wait a week. Pull the pressure release valve, and it should obviously have some CO2 under pressure. Try the beer and check if you can see and/or taste a difference, or if you like the taste.

Your keg may be overcarbonated after it is chilled. Either drink frothy beer or bleed off the pressure release valve. If it's undercarbonated, hook up your CO2 tank and push it out. I find that there is maybe a gallon that seems to be perfectly carbonated in there, and when the sweet spot is getting under carbed, then turn on the CO2. When using an actual dialed in spunding value, your beer will be carbonated at the level you desire. That said, at some point it will become under carbed and you'll have to turn on the CO2.

As mentioned before, you can carbonate with sugar in a keg to a very precise desired level of CO2. This does not have to be guess work, or require bleeding off of pressure or the addition of CO2 from a tank to get that level. The carbonation calculations (built into several calculators available on line) are straight forward.

Regardless of how the keg is carbonated, it's not a standard practice, or even a good practice, to just rely on headspace CO2 to push beer until it becomes noticeably undercarbonated (not to mention slowed to a trickle). Are you doing this because you think it's saving you CO2? There's no reason not to turn on the CO2 right away. At the correct (equilibrium) pressure, no CO2 is being used anyway, until beer is dispensed and the regulator opens for long enough to replenish the CO2 concentration that was reduced because of the pint of new headspace. Getting the CO2 level right in the first place (easy with calculators or tables) and then serving at the equilibrium CO2 pressure is the way to have a perfect pour every time. (That, and using the appropriate length of beer line for the pressure.)

Or, you can suffer with inconsistent pours, and turn the CO2 on and off in a doomed attempt to compensate.

 

[Jayjay1976]

Do it because natural carbonation is vastly superior to force carbing, and besides, there are a lot worse ways to spund your time.

 

[kmarkstevens]

There's no reason not to turn on the CO2 right away.

CAMRA and English style ales don't believe in CO2. I'm also lazy, brew lots of different recipes in varying quantities, so dumping in some priming sugar with some what random results works just fine for me. YYMV

That said, I use the blowtie spunding valve. I am just pointing out that anyone wanting to test out how beer carbonated in the serving vessel versus force carbonating can do it very easily with buying additional gadgets. If you track the gravity closely, one can simply rack to the carboy when there is about 6 points left (eg FG+1010, then rack at 1016).

 

[VikeMan]

I am just pointing out that anyone wanting to test out how beer carbonated in the serving vessel versus force carbonating can do it very easily with buying additional gadgets.

And I'm just pointing out that they can add a precise amount of sugar and avoid creating problems for themselves. Why anyone would recommend "dumping in some priming sugar with some what random results" is baffling to me, honestly. You do you, but I wouldn't recommend it for others.

 

[cactusgarrett]

The carbonation calculations (built into several calculators available on line) are straight forward.

I don't keg carbonate with sugar, but is there a reliable tool for this - keg priming instead of bottle priming? From what I understand, priming 5 gallons in a keg requires a significant less amount of sugar than 5 gallons in separate 12oz bottles due to headspace. All online calculators I've seen don't differentiate keg vs bottles, so the potential to overcarbaronate a keg is high.

Sorry to derail the spunding vs keg conditioning conversation; just wanted to note that there's more to it.

 

[VikeMan]

I don't keg carbonate with sugar, but is there a reliable tool for this - keg priming instead of bottle priming? From what I understand, priming 5 gallons in a keg requires a significant less amount of sugar than 5 gallons in separate 12oz bottles due to headspace.

That's an old myth that just won't die. If you're putting 5 gallons of beer into a corny keg, use the same amount of sugar as you would for bottling. The total headsapce is almost the same. There are a few discussions on this. Here's a recent one:

https://www.homebrewtalk.com/threads/first-keg.691008/#post-9080801
And I can tell you from practical experience that when I've carbonated with sugar in kegs, my CO2 levels seemed bang on what I would have expected in bottles.

 

[Craiginthecorn]

Keg or bottle conditioning also has the advantage of reducing diacetyl, regardless of sugar source. Both the relatively slow fermentation and pressure contribute to this benefit.

 

[cactusgarrett]

And I can tell you from practical experience

Great - this is the stuff I like to hear. Like I said, I don't do it, but for the greater good I thought it might need to be touched on.

 

[SFC Rudy]

When I carbonate in a keg, I use half the amount of sugar as I would for bottles. Works every time. I've also used the full amount with no issues.

 

[Beermeister32]

For naturally carbonated Corney kegs, I usually use 3/4 cup corn sugar, works out to about 4.3 ounces. Heat it with a small amount of distilled or other non-chlorinated water in a pan, take a big funnel and dump it in. Purge headspace 15 cycles.

 

[micraftbeer]

At what point do you start the spunding valve process?

I spent some time staring at and fiddling with the calculations from some website that went into the science behind calculating when is the right time. The takeaway I had was there is a precise way to calculate this. But that was way more complicated than I wanted to deal with, so it seemed like when you get to the last 10% of gravity drop, you crank up the spunding pressure to around ~30 psi, and you should have sufficient sugars left for the yeast to get ~2.5 vols of CO2 (if that's you're thing) if fermenting at around 68-70F. The hardest part is really knowing what your FG will be so you can calculate when you're 10% away (yes, there's a way you can take a sample and let it ferment out on the side and measure FG that way, but that sounded like more trouble than it was worth to me).

Of course, if you spunded at 30 psi through the whole process, you won't have to worry about timing that last 10% right. There is limited info/actual test data of pressurized ferments out there, but what there is out there seems to indicate spunding at 30 psi can lead to higher ester formation. So trying to not crank up your pressure until later in fermentation might be worth it.

 

[hootowl]

The SS Brew Tech spunding valve is a one-way valve that you add Starsan to. Fill to above the line of holes in the unit and you're done. IMO, ANY spunding valve that doesn't send the CO2 through an airlock (or otherwise creates a break between the gas flow and inside the fermenter) is not worth using.

I'm using a manifold from Spike that uses the 1-1/2" triclamp. Has a gauge and a PRV. No airlock. Not sure why you would need an airlock. Doesn't the pressure keep contaminants from entering through the PRV? When it's forced to release it's releasing under pressure... like a one way valve. So are you saying that during the release, contaminants can travel in even though the pressure is pushing out?

 

[Golddiggie]

I'm using a manifold from Spike that uses the 1-1/2" triclamp. Has a gauge and a PRV. No airlock. Not sure why you would need an airlock. Doesn't the pressure keep contaminants from entering through the PRV? When it's forced to release it's releasing under pressure... like a one way valve. So are you saying that during the release, contaminants can travel in even though the pressure is pushing out?

PRV is a one way release at 14psi device. NOT to be used for spunding or fermenting under pressure. I use the spunding valve from SS Brew Tech since it's actually for spunding/fermenting under pressure where you can set it to the PSI you desire. You want to put liquid in the cup (I always use Starsan solution in mine) so that you can actually see the activity. IMO, it's also an additional layer of protection from anything going inside. Especially if you almost fill the fermenter and something gets into the works. With the models I have (CF10) I'm not putting that much into them. Even if I decide to brew a batch that's higher (~12 gallons in) I doubt I'll have anything get into the spunding valve.

 

[hootowl]

PRV is a one way release at 14psi device. NOT to be used for spunding or fermenting under pressure. I use the spunding valve from SS Brew Tech since it's actually for spunding/fermenting under pressure where you can set it to the PSI you desire. You want to put liquid in the cup (I always use Starsan solution in mine) so that you can actually see the activity. IMO, it's also an additional layer of protection from anything going inside. Especially if you almost fill the fermenter and something gets into the works. With the models I have (CF10) I'm not putting that much into them. Even if I decide to brew a batch that's higher (~12 gallons in) I doubt I'll have anything get into the spunding valve.

Thank you. I have a lot of headroom and haven't had any issues with beer getting into the PRV. I modified this valve to allow adjustability. They had it staked to one setting. I cut out the dimple that keeps you from adjusting it. I simply set it low, watch the gauge and adjust the PRV to the PSI I want. In my case using Spike Flex fermentors with the high pressure lid. I have it set at 15psi and keep a good eye on it. I'm using the Spike manifold and the domed lid which gets my PRV way up high.

 

[Jayjay1976]

You don't need an airlock when using a spunding valve.

 

[hootowl]

You don't need an airlock when using a spunding valve.

That's what I think but the higher cost ones using 1.5 triclamp have a reservoir.