Can I fill a keg half way?

Hey all,
I am very new to kegging. I have a friend who I did a co-brew with and who wants to split the beer into two kegs (one for her and one for me). Can I purge the O2 on a half-keg, let it age, and then force carb it like it was a full keg? Does this even work? Any help ya'll can provide would be most appreciated.

You'll just have more CO2 in the keg when it's half full. Make sure you still purge it properly once you fill them.

I use 2.5 and 3 gallon kegs for my beer (more 3 gallon kegs, since I get 6 gallons out). If you're going to be splitting 5 gallon batches often, into kegs, you might want to get the smaller kegs too.

I wouldn't transfer to keg until the batch is otherwise ready to drink. More time in primary means more yeast will settle out before you transfer. The makes for far less sediment in the keg. I typically go 3-4 weeks for moderate (or my 'low') OG batches which are around 1.060. Bigger brews get longer, depending on what they are and such. Once they go to keg, though, they're ready to be carbonated (I use the two week, set and forget, method) and then go to glass. Since I do fill two kegs from each batch, and only put one into the brew fridge from each at a time (has four spots), I have half of the batch (or more if I make a bigger batch) that gets to age in keg. Good way, IMO, to experiment there.

Fill her keg with the full 5 gallons of beer, then use CO2 to push 2.5 gallons to your keg while you hold the air pressure release up. stop transferring when both kegs weigh the same. TADA!

Golddiggie said:

You'll just have more CO2 in the keg when it's half full. Make sure you still purge it properly once you fill them.

I use 2.5 and 3 gallon kegs for my beer (more 3 gallon kegs, since I get 6 gallons out). If you're going to be splitting 5 gallon batches often, into kegs, you might want to get the smaller kegs too.

I wouldn't transfer to keg until the batch is otherwise ready to drink. More time in primary means more yeast will settle out before you transfer. The makes for far less sediment in the keg. I typically go 3-4 weeks for moderate (or my 'low') OG batches which are around 1.060. Bigger brews get longer, depending on what they are and such. Once they go to keg, though, they're ready to be carbonated (I use the two week, set and forget, method) and then go to glass. Since I do fill two kegs from each batch, and only put one into the brew fridge from each at a time (has four spots), I have half of the batch (or more if I make a bigger batch) that gets to age in keg. Good way, IMO, to experiment there.

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Hmm, okay. What do you think about purging the c02 and NOT carbing it for a month? Say I just let it sit in my basement? The beer is relatively low OG (1.058), sat in primary for 2 weeks and then secondary for almost 3 weeks... I'm pretty sure that the sediment formation will be minimal. Would it be okay to just let it chill for a while in my basement? My kegerator is not quite ready yet...

MZRIS said:

Fill her keg with the full 5 gallons of beer, then use CO2 to push 2.5 gallons to your keg while you hold the air pressure release up. stop transferring when both kegs weigh the same. TADA!

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How do you plan on telling when only 2.5 gallons has been transferred?? With no way to see the level in either keg.

As for letting a keg of beer stay in the basement for x weeks... I don't see any issue there. Just be sure to seal the keg, then purge the air/atmosphere from it (fill the keg with CO2 after filling, then purge several times, filling with CO2 between). I usually use 5-10psi to purge, after sealing (some kegs seal at ~10psi, others closer to 15psi). If the yeast you used is a good flocculator, then you've left most behind now.

BTW, with my sanke fermenters, I also use a CO2 push to transfer into serving kegs. This means I don't need to move the fermenters at all before transferring. Not something you can do when just using a siphon (you need gravity to help). So I stir up no yeast/sediment when it's time to transfer.

Golddiggie said:

How do you plan on telling when only 2.5 gallons has been transferred?? With no way to see the level in either keg.

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"stop transferring when both kegs weigh the same. TADA!" - that was in my post.

MZRIS said:

"stop transferring when both kegs weigh the same. TADA!" - that was in my post.

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You're actually making it far more complicated than it needs to be. Plus, how many people actually have two scales that can do this?? IMO, far easier to simply transfer into each keg the correct amount.

BTW, when I'm filling my serving kegs, I have the lid off of the serving keg, but cover the opening with a sanitized (StarSan saturation) cloth/paper towel to keep things from getting into it. I'm able to see the level that the beer is at easily. This way I don't need to worry about overfilling the keg, or releasing the CO2 that comes over with the beer.

work smarter not harder - 2 scales are not required. suite yourself sir!!

case in point: 5 gallons of water weighs 41.7 pounds - so as you transfer, when the keg reaches20lb er so - you know your half way transferred... and you only used one bathroom scale.

Also - this closed transfer system doesn't require any extra sanitation steps or worry if your kegs and lines are already clean ....

Golddiggie said:

Just be sure to seal the keg, then purge the air/atmosphere from it (fill the keg with CO2 after filling, then purge several times, filling with CO2 between). I usually use 5-10psi to purge, after sealing (some kegs seal at ~10psi, others closer to 15psi).

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Okay, thanks! This will be the first time I keg anything, so how do I know what PSI level my keg seals at? And when you say that you usually use 5-10 psi to purge, do you mean that you first seal the keg, then add 5-10psi into it, purge the 5-10 psi, then repeat a few times?

homebrewbeliever said:

Okay, thanks! This will be the first time I keg anything, so how do I know what PSI level my keg seals at? And when you say that you usually use 5-10 psi to purge, do you mean that you first seal the keg, then add 5-10psi into it, purge the 5-10 psi, then repeat a few times?

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Use the regulator on the CO2 tank to see what it takes to stop the keg from hissing around the lid. Then you know.

For the purge, you don't need as much pressure to do the job. So you can dial back to 5psi. Simply pull the pressure relief valve ring (or what the lid has for the release, if it's not a pin lock lid). Let it vent fully, then place the gas QD back onto the post and fill the keg again. With more volume to fill, it usually takes a few more hits to get a full purge (or enough to make it not matter). Typical is 5-8 purges (I believe) with the normal amount of headspace. With more, you might want to do 10.

MZRIS, you need to account for the keg weights too. Not just the liquid inside. Water weight is not identical to beer weight. It might be splitting hairs, but it's better to be accurate than sloppy. I also neither own, nor would trust, a bathroom scale to be accurate in this. I do have a scale that could do the job (use it for my grain, goes to 55#'s) but it's a moot point for me.

Golddiggie said:

Use the regulator on the CO2 tank to see what it takes to stop the keg from hissing around the lid. Then you know.

For the purge, you don't need as much pressure to do the job. So you can dial back to 5psi. Simply pull the pressure relief valve ring (or what the lid has for the release, if it's not a pin lock lid). Let it vent fully, then place the gas QD back onto the post and fill the keg again. With more volume to fill, it usually takes a few more hits to get a full purge (or enough to make it not matter). Typical is 5-8 purges (I believe) with the normal amount of headspace. With more, you might want to do 10.

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Thank you so much, Goldiggie! I really appreciate your help! This sounds very doable!

"Water weight is not identical to beer weight. It might be splitting hairs, but it's better to be accurate than sloppy."

the water weight was an example. you have to do your own weighing - also this is beer making not rocket fuel, but to each his own.

"MZRIS, you need to account for the keg weights too. Not just the liquid inside."

yea yea, i forgot you needed to post every variable possible to get the idea across.

Hmmmm, one more question actually. If I were to just go ahead and carb the beer and let it sit in my basement for a few weeks, would that be okay? Or should I only let it sit if its purged and sealed, but not carbonated?

homebrewbeliever said:

Hmmmm, one more question actually. If I were to just go ahead and carb the beer and let it sit in my basement for a few weeks, would that be okay? Or should I only let it sit if its purged and sealed, but not carbonated?

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Doesn't really matter. But carbonating at higher temperatures needs more pressure (PSI) than at serving temperatures. This chart will show you how much gas you need to use at the different temperatures to attain the CO2 volumes level you desire.

You can also partially carbonate the kegs (lower PSI for 2-3 weeks) if you wish. Then finish the carbonating at serving pressure, once the kegs have reached serving temperature (24-48 hours from going into the brew fridge/keezer/etc.). Just be sure to check the pressure level of the keg once it's been chilled. That way you'll know if you need to purge it to get to the CO2 volumes level or not.

Golddiggie said:

Doesn't really matter. But carbonating at higher temperatures needs more pressure (PSI) than at serving temperatures. This chart will show you how much gas you need to use at the different temperatures to attain the CO2 volumes level you desire.

You can also partially carbonate the kegs (lower PSI for 2-3 weeks) if you wish. Then finish the carbonating at serving pressure, once the kegs have reached serving temperature (24-48 hours from going into the brew fridge/keezer/etc.). Just be sure to check the pressure level of the keg once it's been chilled. That way you'll know if you need to purge it to get to the CO2 volumes level or not.

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Okay, so say my basement is about 65*F right now. So I carb the beer to about 28 PSI (its an anchor steam clone, so around 2.5 CO2 Vols) and let it sit for 2-3 weeks. At about that time, my kegerator will be up and running, so I move it into the keezer, let it chill for 24-48 hours so it gets nice and cold (~45*F), then purge to get the PSI down to around 15 (again, 2.5 CO2 Vols for that temp)? Then I let it sit for awhile to adjust before I can drink it? Or can I drink it right away? Or do I have this whole thing wrong? Ha, sorry, but the kegging process seems so complicated for the first time (as did almost everything else about brewing beer...)

homebrewbeliever said:

Okay, so say my basement is about 65*F right now. So I carb the beer to about 28 PSI (its an anchor steam clone, so around 2.5 CO2 Vols) and let it sit for 2-3 weeks. At about that time, my kegerator will be up and running, so I move it into the keezer, let it chill for 24-48 hours so it gets nice and cold (~45*F), then purge to get the PSI down to around 15 (again, 2.5 CO2 Vols for that temp)? Then I let it sit for awhile to adjust before I can drink it? Or can I drink it right away? Or do I have this whole thing wrong? Ha, sorry, but the kegging process seems so complicated for the first time (as did almost everything else about brewing beer...)

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I would let it sit for a day (or so) once you've gotten it to the right psi at temperature. Purging kicks up the sediment in the keg.

Get one of these, or make one, to test the pressure of the fully chilled keg. If it's close to where you want it to be, then you won't need to purge it. That means you'll be closer to drinking from the keg. :rockin:

Wow, that is a nifty little gadget! Especially because I'll have my CO2 tank and regulator inside of my keezer. I have heard that it takes a while for pressure gauges to accurately read PSI when they are cold (or more specifically, that they take longer to adjust.

A 5# CO2 tank will read 800 PSI on the high pressure side when at room temp. When chilled to serving temp, the same setup will read about 500 PSI. Simply because of the temperature difference.

I have my CO2 tanks outside the brew fridge. For one thing, I have immediate access to the regulator valves. This allows me to see, at a quick glance, the pressures. It also frees up space inside the brew fridge for kegs. Plus, I'm not limited to a maximum CO2 bottle/tank size. I'm currently using a 20# tank (would never fit inside the fridge). I also have a 10#, a 5# and even a single 2.5# tank. Plus, several paintball gun bottles (12-20oz). Chances of me ever running out of CO2 is pretty remote.

Golddiggie said:

A 5# CO2 tank will read 800 PSI on the high pressure side when at room temp. When chilled to serving temp, the same setup will read about 500 PSI. Simply because of the temperature difference.

I have my CO2 tanks outside the brew fridge. For one thing, I have immediate access to the regulator valves. This allows me to see, at a quick glance, the pressures. It also frees up space inside the brew fridge for kegs. Plus, I'm not limited to a maximum CO2 bottle/tank size. I'm currently using a 20# tank (would never fit inside the fridge). I also have a 10#, a 5# and even a single 2.5# tank. Plus, several paintball gun bottles (12-20oz). Chances of me ever running out of CO2 is pretty remote.

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Yes, but from what I understand, the reduction in PSI does not mean that you loose any CO2 and can carb/push just as many kegs as if the tank were at room temperature. I thought about putting my tank on the outside, and maybe I will eventually, but for the space I have, it seems better to keep in in the fridge. As of right now, I can fit 4 kegs plus a 10# CO2 tank in the fridge. Eventually, I may want to do more than 4 kegs, and at that point I'll look into keeping the tank outside my fridge.

The volume of CO2 remains the same at either temperature. Especially since the tanks are filled up by weight. What you really care about is the reading on the low pressure side of the regulator. Make sure that's where it needs to be in order to carbonate/serve the keg(s) and you'll be fine.

Okay, got it. Thanks again for your help!

homebrewbeliever said:

Hey all,
I am very new to kegging. I have a friend who I did a co-brew with and who wants to split the beer into two kegs (one for her and one for me).

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Yes, that’s a good ratio!

O2? Oh, air… wow, a lot going on here.

MZRIS said:

Fill her keg with the full 5 gallons of beer, then use CO2 to push 2.5 gallons to your keg while you hold the air pressure release up. stop transferring when both kegs weigh the same. TADA!

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I think that’s a good idea… what woman, worth her weight, doesn’t have a scale?!? Crap... did I just say that!?!

Otherwise, make sure your sitting keg will have enough co2 to keep the lid on, especially if the beer isn’t carbonated (cool basement and some will go into solution)… you could over carb it and two days before serving / chilling shake it up and let it sit in a warm room and release the pressure release valve every so often.