Why do you have to purge?

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jonmohno

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Just got a new 3 gallon keg kit, I have 2 gallons of Ranger-cloneish in it, not knowing about volume to psi levels, I set it @ 16 thinking I only need half for doing the quick method. I believe Im wrong about that and should have just set it @30 after further researching. Anyway....

Its been 30 hrs and Im wanting to check it, my first glass will be wasted anyway with sediment due to some "hard times" racking from using loose leaf hops. I got more sediment in it than I was bargoning for.I used a hop bag on my siphon to filter and that didnt work so I took it off and got hop leafs stuck in my auto-siphon- I eventually got most of it in my keg loosing a good 3-4 beers. I should have just funnel/strained the last of the carboy that I couldent siphon. Not to mention the little black-flapper -valve came out of the siphon. NOw I got to find a way to put it back in.

So why do I need to purge it before setting it to 10 then dispensing some? And do I need to purge all of it till it stops? Then set it at 10 before dispensing some? I was going to not purge it andsee what happens but I thought Id better ask first since Ive never kegged before.
 
Well,I purged it.Set it to 8 and its carbed and looks like nitrous looks. I hate to say it but its almost too hoppy at this point but its carbonated. So do you just leave the lines open and gas on? set at serving pressure? or do I need to close the valve/valves since its carbed? Do you shut your lines when its carbonated or do you need to keep them open @10psi- until the keg is gone even if you drink it over a period of 2 months?
 
You purge to get the oxygen out. The CO2 is "heavier" so in theory when you fill the keg with gas, the oxygen goes to the top. Purging blows the oxygen out. Do it a few times and walla you have no oxygen to oxidize your beer. Just pure CO2 goodness.

You can keep the gas on or off once its carbed, up to you. Unless you have a leak you are not using any more gas by leaving it on. The beer/headspace will only take so much gas, then no more.
 
How long did you actually wait between your first post and just doing it? :D
Yes, you need to leave the gas on at your serving pressure.
The reason for purging is if you tried to pour a beer at 30 PSI it would shoot out too fast and you would be left with just foam in your glass. no need to completely purge to 0 PSI and then pump it back up. I ususally turn the reg back down to "0", then purge till it drops just under my target temp, then wind the reg back up.
but most of the time I just set and forget for 2ish weeks.
 
You purge to get the oxygen out. The CO2 is "heavier" so in theory when you fill the keg with gas, the oxygen goes to the top. Purging blows the oxygen out. Do it a few times and walla you have no oxygen to oxidize your beer. Just pure CO2 goodness.

You can keep the gas on or off once its carbed, up to you. Unless you have a leak you are not using any more gas by leaving it on. The beer/headspace will only take so much gas, then no more.

Thanks but I was talking about purging it using the quick carb/few day method before you serve it. Yes I did purge it once I initially racked it and gassed it up. Thanks.:mug:
I set it at 8.It seemed to be shooting out fast foamy still even after purging and turning it down to 10. Im now on my second short pour already. :)

Its weird it shot up to 20 psi when I opened the air line valve after I first purged it and I had thought I was turning it down, I was able to get it back down to 10 shortly though. That confused me,does this mean I need to purge it again a little since it shot up to 20-then I just turned it down. Does that mean there is 20 psi in the beer now and just 10 psi in headspace since the regulator was reading 10? Well I did turn it to 8 now because of how fast the second short pour was coming out. Or do I really need to keep it at 10 for the duration?
 
Venting after force carbing prevents having a mess. Without venting the beer would rocket out of the tap, make a bunch of foam and end up flat.
Btw, 16 psi isn't very much to force carb for a day especially if it wasn't already cold.
 
Venting after force carbing prevents having a mess. Without venting the beer would rocket out of the tap, make a bunch of foam and end up flat.
Btw, 16 psi isn't very much to force carb for a day especially if it wasn't already cold.

I cold crashed it.It was cold when I racked it,then it went straight to the fridge.It is 2 gallons in a 3 gallon keg-if that matters I dont know. Should I turn off the small red line valve,purge it again, then open the valve with not touching the regulator which is now set at 8 and see if then comes out flat?
 
I think what he is saying is you might not be carb'd fully yet. I would leave it at 8-10 (whatever your desired CO2 volume requires) for another week, gas on the whole time. From what you said about how it looked when you did pour it I would say undercarbed.
As you mentioned if force caqarbing most would set at 30 psi for a day, and then drop to serving pressure.
 
Well you're already pouring brews and you only had it set to 16psi so I wouldn't vent anymore. Just set it to whatever you want to serve and call it a day. Better to let it be undercarbed for a few days than to have to deal with overcarbing.

The colder the liquid the quicker it absorbs co2 so starting it cold helped.
 
Yeah I do think it is undercarbed and I would be hesitant to crank up the pressure because of the likelihood of overcarbing at this point. It is only two gallons so it shouldn't take more than a few days to be where you want it since you are most of the way there.
 
Cool. I think. I am going with instinct and safety as well. Just being cautious.Im just wondering why its carbed mostly then, considering the norm. I was starting to get paranoid about sediment clogging the metal tube as well causing a bunch of air or something as well. Is this something to worry about?

Kegging seems alot harder to get desired co2 volumes than the standard priming sugar/volume of beer bottleing somewhat so far. I definatly do not want to overcarbonate this.
So are you saying if I would have set it at 30 for two full days,purged then dropped the regulator to 10 that it would have been possibly overcarbed that way?
 
Yes, 30 for two days on a two gallon brew that started cold would likely end up overcarbed. Sediment shouldn't be a clogging problem except in extreme cases.

Set and forget is really the best for carbing and having sediment free brew but it takes too long for me, especially since I only have one line for beer.

For instance my keg kicked last night, I racked another cold brew in the keg and set to 30. I'll leave it at 30 for a day and a half, vent some gas off and set to serving pressure. The first brew is usually undercarbed because I find my diptube doesn't carb as well...yeah I overcarbed before because of that fact.
 
Yes, 30 for two days on a two gallon brew that started cold would likely end up overcarbed. Sediment shouldn't be a clogging problem except in extreme cases.

Set and forget is really the best for carbing and having sediment free brew but it takes too long for me, especially since I only have one line for beer.

For instance my keg kicked last night, I racked another cold brew in the keg and set to 30. I'll leave it at 30 for a day and a half, vent some gas off and set to serving pressure. The first brew is usually undercarbed because I find my diptube doesn't carb as well...yeah I overcarbed before because of that fact.

Thanks man. 3 weeks @10 was a disapointing kegging reality to find out after buying a keg. I never knew that. The more I read, its 3 weeks @10 psi. Just like bottleing 3 weeks 70 deg. GRRR! Well I think Im glad I set mine at 16 for 30ish hrs and decided to drop it now better this than doing 30 and overcarbing it for 2 days. I can tell my beer is needing some "conditioning" anyway Im pretty shure I got a mouthfeel or two of hop sediment/yeast/beer. I racked too much junk too. Id imagine I will get a good pour on my 3rd or 4th in a week or two.
 
So why do I need to purge it before setting it to 10 then dispensing some? And do I need to purge all of it till it stops? Then set it at 10 before dispensing some? I was going to not purge it andsee what happens but I thought Id better ask first since Ive never kegged before.

If I understand your original question. You wanted to know why you purge when your keg is at 16 psi and you lower it to 10psi. The reason is anytime you adjust the regulator to less than keg pressure you should purge the keg so the pressure from the keg doesn't push the beer back into your regulator and mess it up with beer. If you have a check valve it will stop it from entering the regulator but you will still have a gas in line with beer between the check valve and keg. Purging only gets rid of the headspace pressure and doesn't uncarb your beer
 
Ok,Im starting to get this, I poured about 5 oz and started seing it go flat. Although my little 3 oz pour is carbed.So I turned it up to 11 and am going to leave it for at least a week or two now. I still believe I will get a foamy/sediment pour in a week or two but after that I think it will be good to go. My racking was terrible but I can see this turning out good as most bottled beer Ive made.
 
I think its getting steady.I poured some last night came out fast at first,then a steady-slow flatish pour. Ended up with half a glass of foam in a pint glass/so I got about 6-8 oz. Overall it seemed mostly carbed,just 4 finger head( a bit much),I purged then turned it down was going for 8 but ended up at 9 now. I think I will end up lowering it more by the end of the week. A weird chemical taste is kinda there still but fading that I was getting, I keep thinking of the smell of idophor in the keg after sanitizing it,that and some kind of gassy/propaneish like thing. Its fading though.

By the way are you suppose to sanitize your air-line? Every video I see I never see that part being sanitized.
 
Ok. heres an update. This weird chemical taste is annoying. Any chance only rinsing a brand new keg then sanitizing it is bad? Im confirming a aroma/taste that reminds me of what something tastes like when freezer burned,like that almost exactly. I did keg this knowing of a screw up too. In half my mash since I do a double stove top mash to achive 2.5 gallons. I accidently added too much baking soda to one of the mash pots and couldnt bring my mash ph down from it. Im guessing this is it.It reminds me of a gassy propane/freezer burn refrigerated tast of like other food in something like when butter gets other tastes in it.Its actually a pretty good beer just has this. Not shure if I used tap water for the starter in this one as well which Im also suspisious of now. Possiblitly of chlorine in a starter??? Ive used it before with no problems.
Anyway not an ideal first kegging mostly because I already was skeptical before I kegged it. But its still a drinkable beer just has this offness I cant get passed,it reminds me of the smell of the keg/idophor before I kegged it also. Maybe its just my dryhopps are old?? I got them from my lhbs which is semi-unstable sometimes as far as storage/age freshness.I got leaf hops from them thinking(fresh) its a win-win when now I think I just got screwed again from old stuff from the lhbs. Nothing dumpable though,its otherwise good,just doesnt seem to go away. Does anybody ever have issues with Co2 exchange? Is this ever an issue? Because I have another brand new 5 # tank which Im thinking about driving further to fill rather than exchange locally? Im kinda in the dark about kegging here.
 
The off flavor could be from the beer line. If you pour two beers in quick succession does the first one have a stronger chemical flavor? Some people, like myself, are more sensitive to it than others, but some chemical flavors will leach out of standard beer line into the beer as it sits. I switched to accuflex bev-seal ultra barrier lines, and no longer have any issues with the plastic/chemical taste.
 
The off flavor could be from the beer line. If you pour two beers in quick succession does the first one have a stronger chemical flavor? Some people, like myself, are more sensitive to it than others, but some chemical flavors will leach out of standard beer line into the beer as it sits. I switched to accuflex bev-seal ultra barrier lines, and no longer have any issues with the plastic/chemical taste.

Well today, a kegged Ranger I have, I did a back to back with a commercial Ranger. I have an utterly annoying aroma,its not going away and it smells like freezerburn/propane/metal.could it just be old hops I dryhopped with?The beer itself tastes pretty good and quite good now actually( but I didnt brew it spot-on exactly either) but the annoying aroma just makes me kinda not like it. I already new I made a mistake on the batch so Im hoping it is only my mistake and not just kegging in general.

Standard beer line is creeping me out now that you say this, I mean it cant be good if you taste/smell it more than hops. Wow,beer line can overpower dryhopping aroma?? Thats messed up. If I get this same thing with a next batch I keg, I may give up on kegging then, I know I messed up half(used 2 pots to mash) my mash because of adding way too much baking soda accidentally to raise my ph a little then tried to fix it by adding more and more gypsum to get it low but my ph stripwas still reading in the purple. And I was afraid of adding waay too much gypsum at that point so I stopped messing with it.

Is there any way I can just take off the beer line and rinse it then just use it when I randomly pour a pint? I really dont like the fact that beer sits in the line for many days. Something is really affecting the taste/aroma of this my first assumption was the Co2 exchange(thinking dirty/refrigerater-gassy metallic) making it weird. I hope not because I have another brand new 5# co2 tank I would like to fill with clean co2 rather than exchange if thats even an issue with exchanging.

Well, I just poured another pint after about an hour though,I would say its not there as much now but I still notice it a little, hop aroma is pretty minimal also. What do you suggest I do since I only pull a pint of it a few times a week? Pull off the dispenser tube line ? Then just put it on when I want a pint? And pull it off again? Your right though this aroma/taste is going away pulling another pint,didnt pour it back to back (sat in the line about an hour for my second pour)but IM about to go get another just to investigate.At this point my senses are getting a bit dulled so I dont know how "accurate" my results will be. Oh well, its still a good beer only if that "thing" about it would just go away.

Im really hoping its only from the too much baking soda in part of my mash or just old dryhopps?? . The bad smell is way more intense on the first one though,notice it a bit still on the 3rd glass but its not as offensive. I think Im going to rinse my keg with boiled water after sanitizing with the idophor also from now on,Im suspisous of that also, I noticed the keg didnt drain well like it does from tipping bottles upside down which is what I do when bottleing but I do sometimes rinse them with preboiled/cooled water before I bottle. I also want to mention I had a quite a bit of headspace like a gallon maybe. Think I got almost 2 gal into a 3 gallon keg,whether that has anything to do with it too.
 
Another update. Aroma is getting better. Im chaulking this up to ****ty old hops I dryhopped from my damn lhbs. The beer is really good clearing well and now good going on 4 weeks,so Im thinking I got bunk leaf hops. Its a great beer but isnt exactly a ranger,but very good. I wont give up on kegging.
 
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