Strange Maturing Situation With Kegs

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ferretlegs

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Hi Everyone, long time lurker, first time poster.

I've had the HB bug for just over a year now and as I am somebody who likes to put a few away, I have made quite alot of batches over that period :icon_cheers: . I've done tonnes of reading over the last year and have hopefully moved past most of the beginner mistakes. Did about 20 K&K batches and have now moved to extract brewing and using beersmith for the last 40 or 50 batches.

Up until now, I have been able to identify most issues with my resulting beer through reading but there has been one strange thing that I have yet to explain. So I now turn to the collective wisdom of AHB to see if anyone has come across this.

The issue is maturation/conditioning in kegs - I very quickly moved to kegging and kegerator setup after first couple of batches. I usually do 60litre extract batches which basically fills about 3 kegs after leaving them for about 3 weeks in the primary. I usually leave these to room condition for about a week or two, then I chill for a week in one fridge and then gas in the kegerator for a week.

Now ever since I have been kegging, I have noticed that the beer always tastes quite green at the start (of course I pour a few pots into a saucepan to clear sediment first) but the strange thing is that the beer improves markedly every day from that point after tapping. By close to the end of the keg (say 3 days later), its pretty darn good stuff - then it runs out :( Now its surely impossible that the beer has matured suddenly in just those three days. I tested this by leaving kegs for a week or two longer and even shorter (both in warm and cold conditioning), but they never seem to be ready to go first day regardless of how long I leave them. It seems only as the keg is consumed that it improves, very noticably, each day.

So my question is, how can this be? I cant always be drinking the keg right at the perfect time that it is maturing because I have varied the conditioning time by up to 4 weeks. What is it about the keg being consumed that forces the beer to mature faster? My best guess is that there is something about increased headspace, or the fact that most sediment has been drawn off, or some other reason that forces the beer to start conditioning faster. I know that I generally drink my kegs pretty quick (I guess alot of people have this problem) but as I said, I have done the experiment by leaving them the extra weeks to see if that was all it was.

I have taken to the practice of tapping my kegs a bit early with a cheap tap and piece of line, just to get this process going. It seems to help. But I would like to get to the bottom of what is going on here - this process doesnt seem to happen with bottles. So what is happening guys?

Thanks in advance!
 
Just a guess, but it could be that when you first tap the keg, you're getting rid of the yeast and your seeing that as the improvement in flavor.

Do you cold condition your beers in the fermenter or use gelatin prior to kegging?
 
Just a guess, but it could be that when you first tap the keg, you're getting rid of the yeast and your seeing that as the improvement in flavor.

Do you cold condition your beers in the fermenter or use gelatin prior to kegging?
Thanks for your reply - that may be a possibility as I do notice that the beer does progressively clear over those days as well. I dont cold condition the fermenter or use any finings. What I dont understand though, is that if I have pumped out the yeast at the start, why does the beer continue to clear very quickly from there. What I mean is why hasnt the yeast dropped out at all up until this point, and its only after I start to drink it that the yeast decides it better drop out now and hence clear up within a day or so? Why cant that happen at the start before I tap the keg, or what is it about drinking the keg that makes the yeast get on with dropping out?
 
G'day Ferretlegs,

No science to answer your question, but I have (and I'm sure many others have too) found that a keg always tastes its best just before it blows :icon_cheers:

Cheers SJ
 
What I suspect is happening is that you are experiencing a pretty extreme version of the effects of CO2 scrubbing.
Its very important to understand that CO2 doesnt just go into the beer and stay there, there is a constant exchange of CO2 between the head space and beer, CO2 is a very powerful solvent and it will carry other volatiles with it in this case out of the beer and into the head space (as the head space increases volatiles will move into it naturally but the CO2 speeds this up dramatically).
What your question points up is that you have some problem in your brewing process that is filling your beer with undesirable volatile products; I suspect that you need to look at your yeast pitching rate, maybe the quality of your boil (what is your evaporation rate).
3 weeks in primary is too long, why are you leaving your beer there that long, if its to finish the ferment then you must be under pitching or brewing way outside the recommender temperature for your yeast.
I know a lot of guys around here say to primary ferment for 2 weeks, personally I would be reluctant to leave a beer on the yeast cake for that long and would be racking at the end of the first week, but by 3 weeks you could easily be adding some off flavours as the yeast starts to break down.
The very rapid improvement of the beer in the keg is a symptom of a problem in your brewing process, thats what you need to fix.
MHB
 
What I suspect is happening is that you are experiencing a pretty extreme version of the effects of CO2 scrubbing.
It's very important to understand that CO2 doesn't just go into the beer and stay there, there is a constant exchange of CO2 between the head space and beer, CO2 is a very powerful solvent and it will carry other volatiles with it in this case out of the beer and into the head space (as the head space increases volatiles will move into it naturally but the CO2 speeds this up dramatically).
What your question points up is that you have some problem in your brewing process that is filling your beer with undesirable volatile products; I suspect that you need to look at your yeast pitching rate, maybe the quality of your boil (what is your evaporation rate).
3 weeks in primary is too long, why are you leaving your beer there that long, if it's to finish the ferment then you must be under pitching or brewing way outside the recommender temperature for your yeast.
I know a lot of guys around here say to primary ferment for 2 weeks, personally I would be reluctant to leave a beer on the yeast cake for that long and would be racking at the end of the first week, but by 3 weeks you could easily be adding some off flavours as the yeast starts to break down.
The very rapid improvement of the beer in the keg is a symptom of a problem in your brewing process, that's what you need to fix.
MHB
Thanks very much for your reply, I will answer the easy stuff first. The only reason I leave in primary for three weeks is that I have yeast action for about 7 - 10 days and I leave for another week to let things settle out after its died down. To be honest, I was guided about this period by Palmers comments in how to brew who seemed to suggest 3 weeks was OK (section 8.2.3 of the online book). In terms of pitching, I use mr malty's calculator, which recently is about 2 cups of thick re-used yeast slurry, or 3 x packs of saf-us5 if I'm using new - temps are between 20-22c. I'm not sure what my evaporation rate is but I do a 60 minute boil. For my 60l batch, I actually do two boils simultaneously using 2 x 18l pots with about 14l each in them, this 28l is then topped up with water in fermenter - all figured out with beersmith, late malt additions etc to make it all right in terms of hop util etc. (basically a 30litre recipe in beersmith done twice)
I certainly appreciate your comments and I had not considered that the CO2 could be drawing out volatile elements, but I'm still not sure where I have gone wrong in the process. I certainly havent tried a shorter primary run, which is what I will try next. Thanks for the feedback - keep the comments coming everyone!
 
I have experienced beers getting better and also worse in the keg over time (last one lost a lot of hop flavour very quickly for some reason).
I sometimes find initial slightly cloudy pours more flavourfull, possible from the yeast.
I wonder if theres some heavier compounds other than yeast that hang around the bottom of the keg and get drawn out first.
 
Do you do the same recipe each time or chop and change?
 
Do you do the same recipe each time or chop and change?
Same recipe each time, I'm not a sophisticated beer maker yet and wanted to get something basic that works consistently before becoming more fancy. Because I originally came from CUB products, I just make a very simple beer as per following:

1. Bring about 14 litres water close to boil
2. Add 0.5kg pale liquid malt extract and bring to full boil
3. Add 25gm POR in hopsock for 60mins, another 10gm when only 15 mins to go
4. Late malt addition of 2kg also when at 15 mins to go
5. 1.8kg dextrose after flameout
This is done identically in two pots at same time, both pots cooled in sink with running water around it for about 20mins, both then added to same fermenter and topped to 60l - pitch temp is about 24c and drops to our standard room temp of 20-21c overnight, about 12-24hr lag time for full-on krausen. I have also done a few with an additional 500gm crystal malt steeped for 30mins at 75c, this gets added (to one pot only) with 15mins to go as well when I do it.

The only modifications I've done is to play around with the hops a bit to change flavour versus bitterness but thats about it. i.e. less hops for full hour and more in the last 20 mins etc. I always use Saf-US5, though I have been harvesting it on and off, here and there, over last 6 months rather than using new packets every time.
Overall, it all turns out fine if its left long enough (but I always seem to be drinking them too early, but thats my fault), I just cant understand why the main improvement only seems to happen after tapping, rather than leaving it for long enough...
 
+2 for thinking 3 weeks really isn't that long for it to sit in a yeast cake
 

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