Beer batches consistently turning sour

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foxbat

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Sadly I think this batch is also turning sour too. It seems to have lasted longer than others before it was detectable but I'm definitely noticing an increase in acidity. I'm at a bit of a loss really now, I've totally stripped everything down on the last brew and kept things simple with as little messing as possible. I guess the only thing I can think of is the CO2, but I've got 2 bottles from 2 different suppliers and I'm pretty sure I've had the sour issue when using both bottles.

One interesting thing, I just hooked up the full keg to see if there is a difference between that and the keg I've been using and I would say I can taste the sourness on both, but more so on the one with less in that I've been using.
Have you tried taking the pH as the beer matures to confirm that your tastes are correct?
 

mcinnes01

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Have you tried taking the pH as the beer matures to confirm that your tastes are correct?
No that is a good shout I'll do that now. Although I wonder if the fact it's carbonated will reduce the ph slightly anyway?
 

mcinnes01

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So before carbonation it was ph 4.49 now it's about the same pretty much (not sure how perfectly accurate my ph meter is) but within 0.1 of the original value anyway.
 

foxbat

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So before carbonation it was ph 4.49 now it's about the same pretty much (not sure how perfectly accurate my ph meter is) but within 0.1 of the original value anyway.
I guess you're more interested in any decrease over time rather than absolute accuracy.
 

mcinnes01

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I guess you're more interested in any decrease over time rather than absolute accuracy.
Yeah I think you're right, it's much of a muchness. Got one reading 0.1 below and another 0.1 above. I'll probably get a new ph meter the one I have is a bit knackard now but I'm sure is there or there abouts.

My thoughts are currently tending towards an issue happening in the kegs as the beer tasted fine before kegging (and also for a period afterwards). The alternative is that it is something in the wort that develops as the beer matures or something coldside either from in the fermenter or on the way in to the kegs and it develops as it matures. Although I also replaced my racking line with 3/8 beer line and a new 1.5" tc connector for it this time (my old racking line was a little too wide).

Kegwise since I boiled all the disconnects and lids this time, all I can think is something in the dip tube that isn't getting got or in the keg itself. Or I'm perhaps coming back to oxidation, maybe some oxygen pickup in process. Not sure how oxidation tends to present, if its a quick thing or grandually gets worse (as in a set amount of oxygen got in, not that there is a leak and this gradually degrades all the beer in the keg).

Like I say I have been water / co2 purging my kegs for a long while and I even added k-meta to help clean up any additional oxygen.

If it oxygen only thing I can think of is shelling out for a DO meter and measure before and after kegging.

My other thought was something in the co2 side, either the manifold, bottle, regulator of main pipe. I replaced the pipework after the manifold and boiled all the pushfits before kegging this time. Also I have co2 of 2 different suppliers and I've had the issue whilst using both.

Not sure if there is a test I could do that perhaps doesn't require the effort involved in brewing another beer to perhaps identify the issue, but could perhaps pinpoint something between fermenter and keg?

I did wonder if there could be anything in my process that is creating some oxidative precursor compounds or the grain even? I have got a brand new sack of marris otter so I could potentially do a pure base malt brew with that to rule out an issue with grain?
 

Nicks90

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This all sounds horribly complicated and adding loads of this, loads of that, dropping trub, taking samples, millions of parts and pipes and stuff. Each and every stage can cause an issue.

Can I suggest for your next brew you buy 25l ashbeck water, sterilise your fermentation bucket and do a simple ale and add NOTHING to it but yeast.
Leave it for 2 weeks, no samples no gelatin no nothing.
Then use a simple syphon tube and bottle half of it in PET bottles and the rest do what you normally do with kegs and stuff.
In terms of sanitising the bottles, again don't go silly as you may be introducing sour notes through chemical overload.
Rinse the bottles in hot soapy water. Rinse with tap water. Starsan and rinse with tap water again. Yeah I know it's supposed to be no rinse, but I don't want to drink Starsan thank you very much and tap water is clean.
Add 1/2tsp sugar and bottle using a piece of tube as a syphon.

90 ag brews in and only had 2 go wayward.
If the bottles taste good after 2 weeks, it's the messing about that's introducing sourness via chemical or bacteria
 

mcinnes01

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Cool yep my mate just said something similar in terms of splitting the batch to see if one process causes the issue over another. I could definitely give bottling a go. I've got a plastic bucket fv I used previously so I could even split half in my chronical and half in the bucket I suppose.

In terms of dumping trub I only did this twice on the last batch in order to get it below the racking port on the fermenter, I guess that is always required in a conical fermenter vs a bucket though. I did conciously try to keep the messing about to a minimum really with this beer other than fining it really. Yes there are some chemical additions which I suppose you can say are complications, but even in a rudamentory wine bucket / demijohn setup you would add some sodium metabisulphite and finings. There was also a lot less starsan contact with this beer which I agree is an acid in and of itself and I was a little perplexed by the no-rinse nature when I first started. However this beer was kegged using k-meta / water solution to purge the kegs instead of starsan. I could try rinsing I guess with boiled water in terms of any racking tubing after santising like you say.

I also thought this was a fairly simple brown ale too, so short of going to a smash ipa I'm not sure how much more simple I can go recipe wise.

I was thinking maybe do 46l batch just using my new marris otter and maybe 150g of citra in kettle additions (similar to the brown ale). I won't adjust my water chemistry and I will just add yeast nutrients and a protofloc as usual.

I'll split 23l in my chronical, 23l in my bucket fermenter.

I'll clean as usual, sanitise then rinse with boiled water on both and my transfer pipe.

Then a packet of verdant yeast in both and leave for 2 weeks. My chronical I can temperature control, the bucket will just have to deal with a range of temps between about 15 and 19 as I have no other means of controlling that. I won't cold crash to avoid oxygen pickup and obviously this isn't possible on the bucket.

I'll then keg some of each fermenter and bottle some of each fermenter. I'll rinse the kegs and components with starsan and boiling water and liquid purge as usual. I'll follow the bottling process above.
 
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Nicks90

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I did conciously try to keep the messing about to a minimum really with this beer other than fining it really. Yes there are some chemical additions which I suppose you can say are complications, but even in a rudamentory wine bucket / demijohn setup you would add some sodium metabisulphite and finings. There was also a lot less starsan contact with this beer which I agree is an acid in and of itself and I was a little perplexed by the no-rinse nature when I first started
Nope
Cant say I have ever 'fined' a beer, or added metaB to any brew I have ever done. Why? They all drop clear anyway and why force stop the yeast by poisoning it with chemicals?
Bang it in a bucket and let it do its thing till its done. I don't even lift the lid on mine, not even once, till the 2 week mark. I then take a peek and if it looks done I'll then put it in my cellar for a couple of days to drop clear, then bottle it.
In fact I will let you in to a secret.... I haven't taken a final gravity reading on probably the last 20 brews. I know the yeast profile of the yeasts I use and know that yeast X will attenuate blah% and should finish in 5 days at 20c according to the yeast data sheet. So 14 days at 18-20c will mean it's either a) done b) totally f%@ked and will be rank.
I take the FV up to the kitchen and draw off a half pint to prime my syphon tube and take a taste. If its tastes good I start cleaning bottles and bottle it up.
Job jobbed
Don't over think it
 

mcinnes01

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Ok I've got an interesting update, out of the 2 corney kegs full I started with, I transfered 5l to a mini keg from one of them. As I said the beer was fine at first, then after a few days or week started to develop a mild acidity and eventually turned very acidic. The 5l I transfered to the mini keg is still drinkable now, and ony has a mild acidity.

To me I feel the mild acidity in the mini keg was perhaps oxygen that was present in the beer from the previous keg and although it has slightly increased in acidity from when I first transferred beer to the mini keg, it has oxidised at a much slower rate. I feel like that is just the action of the existing oxygen in the beer and it has stopped or slowed the beer oxyidating much further than the 2 original corney kegs.

Is there a way I could be doing something wrong with my kegs where by oxygen is some how getting in to them after the beer is in them? I'd have thought the positive pressure of the co2 would prevent this but maybe there is something happening, like some form of venturi action in the co2 lines pulling in some oxygen, or some issue with the seals, disconnects or o-rings etc? They were brand new AEG kegs and are still in perfect condition as far as I can see. I've had the kegs about a year and haven't had issues previously with them, but now I am getting a consistent issue once with beer is kegged.

My co2 setup is Regulator with pushfit 3/8 connector, to manifold with 3/8 push fit connector. Then the manifold splits to out to 4x 5/16 pushfits. I tend to only use one of these for 2 kegs and then there is a pushfit 3/8 T in the kegerator and I then have the check valve gas disconnects on either end of the T again with 3/8 pushfits.

I have in the past had a few issues where my co2 has escaped if the pipe is on a tight angle to a pushfit connector, but I did replace all the gas line as I said this time and was consciously trying to check for and avoid and connection pulling on a tight angle in the pushfits.
 

mcinnes01

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I fully fill the kegs with santisier (or k-meta solution this time) then purge them with co2 and then close pressure transfer in to the sealed kegs. I tend to pressure them up to 3 bar before I do my closed transfer then drop the pressure down to the same as the fermenter (2psi), to ensure the lids have sealed properly on the kegs.
 
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Do you leave your CO2 on all the time or switch it off between bursts?

If you switch it off, do you ever remove the gas disconnect?

If you do, do you then purge the gas pipe before you connect the disconnect to the keg?
 

mcinnes01

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Since letting my gas go I tend to turn it off between bursts, but I don't disconnect anything else. I did make sure I purged the gas lines before connecting the disconnects and afterwards to ensure there was no co2 in.
 
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I’m clutching at straws a bit now but there are two things that I can think could be possibilities (in theory anyway)…

First, you have an infection (acetobacter) in one or both of your 19l cornies but not in your 5l (or didn’t have) so the infection in the 5l is only whatever you brought in with the beer. The infection in the 19l is more established and having a greater impact.

The other possibility (maybe): When you turn off your CO2, and assuming you are using a manifold with a check valve, the pressure in the gas pipe from the gas bottle to the manifold may seep away if your seals are not perfect. This opens up the possibility for air to get into that pipe. When you open up the gas valve you push that air into your keg. It’s a long shot but if you have no other candidates this might be worth exploring. You’d just need to not switch off your CO2 to test this one - but would need a fresh brew first.

The other option of course is that you’ve already oxidised your beer some time after primary fermentation but I’m sure that must have been explored and discounted.
 

mcinnes01

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Thanks for your ideas, I too am clutching at straws a little so any thoughts are more than welcome :)

I'm hoping to get a brew in either just before or just after new year, so I'll perhaps try to incorporate some of your potential ideas. My friend is a 5 gallon glass carboy brewer and he always rinses it with boiling water prior to filling, so perhaps on top of a deep clean of my kegs and the dip tubes I could also adopt this idea prior to co2 purging.

I know a lot of the LODO guys like to use boiled water so perhaps I'll maybe start following some of those processes, including filling the kegs with boiled water for purging instead of just tap next time. I've also got a few different mash options on my kettle and the last few brews I've used the sparge hat or sparge manifold which both spray wort over the grain during the mash. I may go back to the pipe sat on the grain bed to reduce introducing more oxygen whilst mashing or maybe look at a sparge manifold I can sit on top of my grainbed to distribute it a little more evenly. I've also read about pre-boiling your water and using some sodium-metabisulphite to remove oxygen from your mash and sparge water, so maybe I'll give that a go too.

I'll report back after my experiments 🙂

Any ideas in terms of acetobacter if there are any test I can do for it's presence? I have a reasonably powerful microscope so I could try swabbing and cultivating some plates although I haven't done this since A level science 😆
 
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I am wondering if your starting mash temp is too low - it does sound very low to me - I usually start at 63/65ish depending.

Temps in the low 50s will encourage bacterial activity that will produce a sourness. The bacteria will be killed in the boil but the sourness will remain

Why do you feel you need to do a protein rest at all with today's modern well processed malts?

How about trying a brew where you start at 65 and don't drop below during the mash and see what that does
 
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Thanks for your ideas, I too am clutching at straws a little so any thoughts are more than welcome :)

I'm hoping to get a brew in either just before or just after new year, so I'll perhaps try to incorporate some of your potential ideas. My friend is a 5 gallon glass carboy brewer and he always rinses it with boiling water prior to filling, so perhaps on top of a deep clean of my kegs and the dip tubes I could also adopt this idea prior to co2 purging.

I know a lot of the LODO guys like to use boiled water so perhaps I'll maybe start following some of those processes, including filling the kegs with boiled water for purging instead of just tap next time. I've also got a few different mash options on my kettle and the last few brews I've used the sparge hat or sparge manifold which both spray wort over the grain during the mash. I may go back to the pipe sat on the grain bed to reduce introducing more oxygen whilst mashing or maybe look at a sparge manifold I can sit on top of my grainbed to distribute it a little more evenly. I've also read about pre-boiling your water and using some sodium-metabisulphite to remove oxygen from your mash and sparge water, so maybe I'll give that a go too.

I'll report back after my experiments 🙂

Any ideas in terms of acetobacter if there are any test I can do for it's presence? I have a reasonably powerful microscope so I could try swabbing and cultivating some plates although I haven't done this since A level science 😆
You can Google tests for acetobacter but you can just strip down the keg and give all the parts a soak in bleach. You will obviously need to give it all a damn good rinse afterwards. You can then reassemble, wash and sanitise as usual. I would personally replace all the rubber seals too even if this shouldn’t be necessary.

You could do this with one keg and if it fixes the problem do the same with the other.
 

moto748

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I am wondering if your starting mash temp is too low - it does sound very low to me - I usually start at 63/65ish depending.

Temps in the low 50s will encourage bacterial activity that will produce a sourness. The bacteria will be killed in the boil but the sourness will remain

Why do you feel you need to do a protein rest at all with today's modern well processed malts?

How about trying a brew where you start at 65 and don't drop below during the mash and see what that does

That sounds a sensible and simple idea which is surely worth a try.
.
 
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I am wondering if your starting mash temp is too low - it does sound very low to me - I usually start at 63/65ish depending.

Temps in the low 50s will encourage bacterial activity that will produce a sourness. The bacteria will be killed in the boil but the sourness will remain

Why do you feel you need to do a protein rest at all with today's modern well processed malts?

How about trying a brew where you start at 65 and don't drop below during the mash and see what that does
The OP reported the beer is fine for a few days and then the off-flavour starts to develop.
 

mcinnes01

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Yes I can certainly try a single step mash, the low temperature first step I've adopted more from brewing thick mashes on some of my neipas or dipas and for proteolytic enzymes and beta-glucanase activity. I was finding it helped a little to avoid a stuck mash and improved my efficiency, but I think I'll continue with a simple smash ipa whilst I root out this issue so it probably isn't necessary. I have also read a few bits and pieces around the protein degradation being seen as more of a job for the maltster so I'm happy to skip that step and see if it helps.

Out of interest do you have any more details or can point me in the direction of some more info around what souring bacteria opperate in these lower ranges or is it the lactobacillus genus again?

In terms of my kegs, I think you're right I'll try some fairly aggressive cleaning this time and see where I get and I've been meaning to get some new o-rings for my valves so some new rubber seals for the kegs seems sensible too.
 
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