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Corny Keg actual volume redux

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ChiknNutz

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Looking at moving up to kegs and have found some contradicting information regarding the actual volume of a corny keg. Most of the resources I've found suggest they are just a bit over 5 gallons, like maybe 5-1/4. One resource I found says they are closer to 6 gallons. The reason for my question is am considering going the route of corny keg fermentation for 5 gallon batches. I am in the market for another fermenter and want to move towards kegging so this will serve both purposes. Who can provide the truth?

Additionally, it seems the ball lock variety is preferred which I presume is due to more accessories being available for ball locks than pin locks. Is this the main reason or are there other reasons to ensure ball lock over pin lock? Many thanks.
 

day_trippr

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I have many versions of 5g ball lock kegs that I cut the gas dip tubes down to stubs. I can fit 5-1/4 gallons in any of them before overflowing the prv. But more than 5 gallons will slow down carbonation.

Cheers!
 

Transamguy77

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@Pfhredd that is a pretty good article, I think ball locks are more common because they are more narrow and can fit more into a chest freezer than pin locks.
 

Sebastian Weetabix

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Easiest way to tell the difference between ball lock and pin lock.

Ball Lock = Pepsi
Pin Lock = Coke
Coke is shorter and fatter whilst Pepsi is tall and thin.
I have used this criteria for the past twenty years and I’ll use it for the next twenty.
 

day_trippr

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fwiw, pin lock technology was a Coke brands exclusive. Everyone else used ball locks.
And there are now a lot of kegs that were converted from pin lock posts and burst-style PRV lids to ball lock posts and auto-reset/manual PRVs.
I have no idea which holds more - I assume as the OP is thinking of fermenting in them the largest volume would be the way to go...

Cheers!
 
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ChiknNutz

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Thanks for the input. I read up on the differences betwixt the two and don't see one as superior, just different. One may be better for a given scenario than another. In regards to capacity, seems that Corneykeg.com may be overly optimistic on the volume. It appears you can use them as a fermenter with some concessions and workarounds, but add'l volume would be a lot better I think. I saw a thread on here about 6.5 G corny kegs offered by William's Brewing a couple years ago, but seems poor quality led them to quit carrying them (and there were of Chinese origin). That would be the sweet spot I think. I've also seen the 7.6G Kegmenters but then you are approaching the same price point of more purpose-built fermenters like Spike, SS Brewtech and such.
 

corax

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I don't think there's anything inherently superior about ball-locks, but don't underestimate the importance of the availability of accessories and (especially) replacement parts. I've had pin-lock kegs for many years, and while they work well enough, it's getting very difficult to keep them maintained due to the scarcity of parts. I don't think it's even possible to get a new post anymore, and the used ones you can find are hit and miss.
 

Dr_Jeff

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Back at home I have a number of extra posts for the Cornelius brand of pin lock kegs, and possibly a few of the Spartanburg posts, what do you need?
I'll be returning home in mid June.


I don't think there's anything inherently superior about ball-locks, but don't underestimate the importance of the availability of accessories and (especially) replacement parts. I've had pin-lock kegs for many years, and while they work well enough, it's getting very difficult to keep them maintained due to the scarcity of parts. I don't think it's even possible to get a new post anymore, and the used ones you can find are hit and miss.
 

cmac62

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In our brew club only one member uses pin lock so we had to put at least one pin lock line on our bar build. If you want to take your brew anywhere you will need to ensure pin locks are supported. Ball locks are most likely the standard for homebrew events. :mug:
 

lump42

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Looking at moving up to kegs and have found some contradicting information regarding the actual volume of a corny keg. Most of the resources I've found suggest they are just a bit over 5 gallons, like maybe 5-1/4. One resource I found says they are closer to 6 gallons. The reason for my question is am considering going the route of corny keg fermentation for 5 gallon batches. I am in the market for another fermenter and want to move towards kegging so this will serve both purposes. Who can provide the truth?

Additionally, it seems the ball lock variety is preferred which I presume is due to more accessories being available for ball locks than pin locks. Is this the main reason or are there other reasons to ensure ball lock over pin lock? Many thanks.
If you're looking to ferment in kegs, a couple options are to brew smaller batches (4-4.5 gal), purchase some 10 gal corny kegs to ferment 5 -5.5 gal batches, or convert Sanke kegs. One of the problems with 10 gal corny kegs is availability. Used ones are far and few. New ones can be pricey. MoreBeer did recently released 10 and 15 gal Torpedo corny kegs. They look like Sanke kegs with corny posts and lid.

New 1/2 bbl (15.5gal) sanke kegs ones run around $120-180. 1/4 bbl sankes run $100- Remove the spear and valve and use a 2" TC adapter. 1/2 bbl a bit large for a 5 gallon batch though. It can still be done, they'll just take up more space. The 1/4 bbl would take up about the similar space as corny kegs.
 
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ChiknNutz

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I am starting to lean strongly towards the 7.6G Kegmenter, then push over to corny kegs for serving. I am reading up on pressurized fermentation and this is an enticing option with any chamber capable of holding pressure. I have just barely started to research what all that entails, but seems like something I'd like to do. Correct me if I am wrong, but doesn't this also perform natural carbonation at the same time? If so, this approach is becoming very appealing. There will definitely be some costs associated with going this route as I have none of it now...kegmenter, corny keg, CO2 tank, spunding valve, add'l fridge, misc fittings and hoses, etc. Still, after botting my last batch, I have quickly grown weary of bottling and want to move on from that, except for maybe the occasional bottling.
 

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I am starting to lean strongly towards the 7.6G Kegmenter, then push over to corny kegs for serving. I am reading up on pressurized fermentation and this is an enticing option with any chamber capable of holding pressure. I have just barely started to research what all that entails, but seems like something I'd like to do. Correct me if I am wrong, but doesn't this also perform natural carbonation at the same time? If so, this approach is becoming very appealing. There will definitely be some costs associated with going this route as I have none of it now...kegmenter, corny keg, CO2 tank, spunding valve, add'l fridge, misc fittings and hoses, etc. Still, after botting my last batch, I have quickly grown weary of bottling and want to move on from that, except for maybe the occasional bottling.
I just got a kegmenter, and it is well made. Comes with a floating dip tube, so it's easy to rack off above the yeast/trub cake. I think the tube length on the floating dip tube needs to be tuned so that the pick up end stays submerged better than with the stock length tube. The thing is very large in diameter. It won't fit in the 7 cu. ft. chest freezer I have been using as a fermentation chamber.

Brew on :mug:
 
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ChiknNutz

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I just got a kegmenter, and it is well made. Comes with a floating dip tube, so it's easy to rack off above the yeast/trub cake. I think the tube length on the floating dip tube needs to be tuned so that the pick up end stays submerged better than with the stock length tube. The thing is very large in diameter. It won't fit in the 7 cu. ft. chest freezer I have been using as a fermentation chamber.

Brew on :mug:
Are you using it for pressurized fermentation and/or carbonation too? I am just learning about it, but seems like a good process. The Kegmenter seems like a good value proposition given the versatility.

I am still on the fence about an FC as my basement does a remarkable job of maintaining good fermentation temps. Though it of course doesn't allow for cold crashing, which I so far don't need but may at some point.
 

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I've only done one fermentation so far, and it was not pressurized, for the most part. Towards the end, I would swap the blow-off tube for a pressure gauge. If the pressure built up, fermentation was still going, so I'd swap back to the blow off tube.

For the initial part of the fermentation, I took the poppets out of the keg post and QD, so that they would be less likely to clog if I got krausen blow off.

My main reason for getting is was primarily for O2 avoidance during cold crash and kegging.

Brew on :mug:
 

Carolina_Matt

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I ferment/serve out of kegs. When I measured it a while back, the keg (ball lock) was about 5 1/4 gallons.

I measured 5 gallons and put it into the keg, and it went right up to the top of the cylinder. That's where I try to fill my wort to as well. Then I use the curved top for headspace, and that's probably about 1/4 gallon.
 

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I can tell you for a known fact that every ball lock keg I have is JUST BARELY over 5 gallon capacity. Doubt it is even 5.25 but maybe. Could be possible to rig something up, but I would not want to ferment a 5 gallon batch in one. For starters, my 5 gal batches are roughly 5.5gal into the fermenter usually, and definitely wouldn't fit if you want a true 5 gallons of finished beer. Random other comments:

-Ball lock is definitely the way to go; the availability difference vs. pin lock is massive, at least today.
-Fermentation temp control would be non-negotiable for me, and prioritized ahead of anything else you are talking about.
-I'm a fan of the Fermentasaurus/Fermzilla family of fermenters for your pressure-fermentation needs. They are relatively cheap and light weight and hold plenty of pressure. Being an ale guy, I've never actually fermented under much pressure though; I just use them for when I'm going for absolute max possible oxygen exclusion or know I will definitely want to cold crash (NEIPA, etc). For my purposes I have an open blowoff tube most of the way, but when fermentation is winding down I replace that with a spunding valve and then do cold crash/closed pressure transfer to a fully purged keg.
-I still do plenty of batches in normal fermenters too (ported plastic Big Mouth Bubblers are my go-to) and in terms of O2 exclusion, I just don't cold crash in those, but still drain through the port to a purged keg. So the only O2 coming in is in the air entering the headspace during the transfer. As long as there is a layer of hop material and/or I stop before air enters the transfer hose, I've never noticed any issues and feel this method is going to be pretty good and far less prone to oxygenation than open transfer to a separate bottling bucket, bottles, etc.
 
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ChiknNutz

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I can tell you for a known fact that every ball lock keg I have is JUST BARELY over 5 gallon capacity. Doubt it is even 5.25 but maybe. Could be possible to rig something up, but I would not want to ferment a 5 gallon batch in one. For starters, my 5 gal batches are roughly 5.5gal into the fermenter usually, and definitely wouldn't fit if you want a true 5 gallons of finished beer. Random other comments:

-Ball lock is definitely the way to go; the availability difference vs. pin lock is massive, at least today.
-Fermentation temp control would be non-negotiable for me, and prioritized ahead of anything else you are talking about.
-I'm a fan of the Fermentasaurus/Fermzilla family of fermenters for your pressure-fermentation needs. They are relatively cheap and light weight and hold plenty of pressure. Being an ale guy, I've never actually fermented under much pressure though; I just use them for when I'm going for absolute max possible oxygen exclusion or know I will definitely want to cold crash (NEIPA, etc). For my purposes I have an open blowoff tube most of the way, but when fermentation is winding down I replace that with a spunding valve and then do cold crash/closed pressure transfer to a fully purged keg.
-I still do plenty of batches in normal fermenters too (ported plastic Big Mouth Bubblers are my go-to) and in terms of O2 exclusion, I just don't cold crash in those, but still drain through the port to a purged keg. So the only O2 coming in is in the air entering the headspace during the transfer. As long as there is a layer of hop material and/or I stop before air enters the transfer hose, I've never noticed any issues and feel this method is going to be pretty good and far less prone to oxygenation than open transfer to a separate bottling bucket, bottles, etc.
Thank you for the insight! Based on everything I've researched so far, I think I'd rather ferment in something larger than a corny keg. I am still looking into the Kegmenter but if the only real draw is it is a larger keg, it may not be a good value overall. Many suggest pressure transfers are a good thing, so that is one of my considerations and several vessels offer that w/o spending hundreds to get there.

Regarding your point about fermentation control, perhaps I should bump this up the list of priorities after all. I don't fancy frequent ice bath changes, so I think the most cost effective and convenient method is a dedicated fridge or freezer with an Inkbird setup. If this is a dedicated FC, then I will need two fridges (one for FC and one for kegs). Wasn't really wanting to do that just yet, just a lot to bite off at one time.

Regarding the spunding valve, do you vent to ambient or have it connected to another keg to salvage the CO2? I've looked a bit into spunding valves, but most of the ones I've seen so far seem to just vent to ambient air and don't have a means to connect a line to the pressure relief side. Are you using the spunding valve merely as a means to build up pressure in the fermenter so you can pressure transfer?
 

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I got the kegerator first and kept doing the ice baths for a while, but there is no comparison; get a dedicated ferm chamber as soon as you can.

For the ferm chamber, mine is a craigslist chest freezer that I got for $125; it was about a year old. 7.5cu ft I think. It will hold two normal carboys with ease. The fermentasaurus sticks up a bit, so I made a top for it out of construction insulation sheets from Home Depot with a custom hole for the top of the fermenter and it works great. The other benefit is that I can get to the gas/liquid posts without opening up the chamber. I just wrap the exposed part in towels to insulate/keep the light out. The liquid level is still well below the top part that is sticking out.

The spunding valve vents to the air, but during primary fermentation I will hook up the blowoff tube to a keg or two and use the fermentation gas to purge. It is a good way to save some bottle gas for sure, works great. You could probably purge a dozen kegs from one 5gal fermentation if you wanted... I don't have that many. I just have some extra tubing; gas to gas and liquid to liquid jumpers for whatever setup I'm doing.
 

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I got the kegerator first and kept doing the ice baths for a while, but there is no comparison; get a dedicated ferm chamber as soon as you can.

For the ferm chamber, mine is a craigslist chest freezer that I got for $125; it was about a year old. 7.5cu ft I think. It will hold two normal carboys with ease. The fermentasaurus sticks up a bit, so I made a top for it out of construction insulation sheets from Home Depot with a custom hole for the top of the fermenter and it works great. The other benefit is that I can get to the gas/liquid posts without opening up the chamber. I just wrap the exposed part in towels to insulate/keep the light out. The liquid level is still well below the top part that is sticking out.

The spunding valve vents to the air, but during primary fermentation I will hook up the blowoff tube to a keg or two and use the fermentation gas to purge. It is a good way to save some bottle gas for sure, works great. You could probably purge a dozen kegs from one 5gal fermentation if you wanted... I don't have that many. I just have some extra tubing; gas to gas and liquid to liquid jumpers for whatever setup I'm doing.
This is a great idea! So would you hook up multiple kegs in a series from the fermenter, and put your spunding valve on the last one? I'm doing about 14 gal batch of cider in my shiny new Fermzilla AR 60L tomorrow. I could see purging all 3 serving kegs like this with Star San in the first one. Is there a practical way to determine if the kegs are fully purged without buying a gas flow meter?
 

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I got the kegerator first and kept doing the ice baths for a while, but there is no comparison; get a dedicated ferm chamber as soon as you can.

For the ferm chamber, mine is a craigslist chest freezer that I got for $125; it was about a year old. 7.5cu ft I think. It will hold two normal carboys with ease. The fermentasaurus sticks up a bit, so I made a top for it out of construction insulation sheets from Home Depot with a custom hole for the top of the fermenter and it works great. The other benefit is that I can get to the gas/liquid posts without opening up the chamber. I just wrap the exposed part in towels to insulate/keep the light out. The liquid level is still well below the top part that is sticking out.

The spunding valve vents to the air, but during primary fermentation I will hook up the blowoff tube to a keg or two and use the fermentation gas to purge. It is a good way to save some bottle gas for sure, works great. You could probably purge a dozen kegs from one 5gal fermentation if you wanted... I don't have that many. I just have some extra tubing; gas to gas and liquid to liquid jumpers for whatever setup I'm doing.
This is a great idea! So would you hook up multiple kegs in a series from the fermenter, and put your spunding valve on the last one? I'm doing about 14 gal batch of cider in my shiny new Fermzilla AR 60L tomorrow. I could see purging all 3 serving kegs like this with Star San in the first one. Is there a practical way to determine if the kegs are fully purged without buying a gas flow meter?
There is a limit to how many kegs you can purge from one 5+ gal fermentation. The more kegs you have in the chain (the more volume that needs to be purged), the higher the residual O2. I did an analysis here for purging a single 5 gal keg. With kegs in series, the last keg will have higher residual O2 then the first keg in the chain. Unfortunately, there is no way to calculate how bad that effect will be. But then, I can't think of a reason that you need to purge more than one 5 gal keg for one 5 gal batch of beer - you don't need two kegs for one batch (if the kegs match the batch size.)

If you are purging kegs with a spunded fermentation, it's better to put the spunding valve on between the fermenter and the keg(s) than at the end of the chain.

Brew on :mug:
 

DVCNick

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I guess you could hook up a bunch in series if you wanted, and put a spunding valve on the last one if you wanted the whole system (i.e. your fermentation) to be under pressure, but I haven't done that. Also I only have one each liquid to liquid and gas to gas jumper hoses made up.

My "on deck" keg is filled as full as I can get it with starsan at all times. If I'm using a non pressurized carboy, I purge the keg with bottle gas, into another keg. Fill the purged keg with beer, and the keg full of starsan is now the "on deck" keg.

However, if I'm using the fermetasaurus I have a ready source of pressurized Co2 during the fermentation, so might as well use it. I push starsan from one keg to the next just like I do with bottle gas; it just takes a little longer. It is still shockingly fast at peak fermentation though... I want to say as little as a couple hours at high krausen? I just leave the second (receiving) keg open and when I see bubbles coming up, I know it's done; I pull the empty/purged keg from the system, move the full one to the front of the line, and repeat. Then I have an extra liquid purged keg saved for another batch.

I only have four kegs so that's the end of it for me, but if you have enough hoses and kegs I'm sure you could set them up to purge a whole bunch in series without having to touch it.
Since I'm liquid purging, I'm pretty confident the oxygen content is very low, but if you are just spraying C02 into an air filled keg I'm sure it takes longer to get an acceptable concentration.
 

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I've never measured the volume in a corny keg, but I typically allow a full gallon of headspace to avoid blowoff disasters. I've been brewing 8-gallon batches and splitting the wort across two kegs that I tee together then vent via spunding valve.

I've been pondering the idea of high-gravity brewing and post-fermentation dilution, but haven't tried it yet: have any ferment-in-the-keg folks tried high gravity dilution?

The BlowTie spunding valve has a push-connect fitting on the outlet so it's easy to makeup a jumper line to use the gas to purge an empty keg
 
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