Off taste after 4-6 weeks in Corni kegs

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JCU

Off taste after 4-6 weeks in Corni kegs

Post by JCU » Tue Jun 06, 2017 7:03 pm

Hello All,

The last three all grain brews I've made have all turned sour (slightly acidic) after approx 4-6 weeks storage in Corni kegs. The beer tasted OK before. Have been using the same equipment and methods for 2 years now.
Do you have any suggestions to help elimimate this problem?

BREWING EQUIPMENT
90L steel HLT & lid & sight glass & tap - with gas burner placed underneath
90L steel Mash Tun (insulated) & lid & sight glass & steel filtre & tap (covers diameter of mash tun) - also used as Fermentation Vessel
90L boiler & lid & sight glass & hop filtre tube (metal) & tap - with gas burner placed underneath
Electric pump and hoses to transfer liquor and wort from vessel to vessel
Metal Heat Exchanger and hoses to cool wort before fermentation
Metal ladel for mixing GRIST and liquor
Plastic bucket for grist mixing
Plastic jug for recirculation of wort in Mash Tun
BRIX meter
Hydrometer & test tube

STERILISATION
Starsan mixture used to rinse and soak (5 mins) for all equipment.

BREWS
Typically 65 Litre brews (fermentation vessel). English and Americal IPAs, bitter etc. Ingredients Maris Otter, crystal and chocolate malts, torrified wheat, English hops, protofloc tablet, AMS & DWB water treatments, Safale 04 yeast.

Thank you

Haydnexport
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Re: Off taste after 4-6 weeks in Corni kegs

Post by Haydnexport » Tue Jun 06, 2017 7:57 pm

strip every fitting you have and deep clean everything then soak with a diluted bleach solution or similar. Pay close attention to your heat exchanger and hoses and tap from boiler. Starsan wont kill wild yeast . What yeast are you using? Harvested or fresh everytime?

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Sadfield
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Re: Off taste after 4-6 weeks in Corni kegs

Post by Sadfield » Tue Jun 06, 2017 7:58 pm

Everything post boil needs cleaning with oxycleaner, if you have any beer stone build up use a soak in starsan to remove it, then bleach. That should kill pretty much everything. This included the tap on your kettle if you have one. Strip down as much as you can, ie taps, filters etc, but avoid scrubbing plastics with abrasive cleaning pads.

Your mash tun is also your fv? I wouldn't do that as grain naturally contains Lactobacillus, a souring bacteria that is present in the mash in considerably greater quantities than would be in a dedicated fv. Boiling kills what ends up in the wort, but you'll be asking a lot from starsan to kill what's remains in the mashtun. Remember starsan sanitises, not sterilizes.

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mozza
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Re: Off taste after 4-6 weeks in Corni kegs

Post by mozza » Tue Jun 06, 2017 8:20 pm

JCU wrote:Hello All,

The last three all grain brews I've made have all turned sour (slightly acidic) after approx 4-6 weeks storage in Corni kegs. The beer tasted OK before. Have been using the same equipment and methods for 2 years now.
Do you have any suggestions to help elimimate this problem?

BREWING EQUIPMENT
90L steel HLT & lid & sight glass & tap - with gas burner placed underneath
90L steel Mash Tun (insulated) & lid & sight glass & steel filtre & tap (covers diameter of mash tun) - also used as Fermentation Vessel
90L boiler & lid & sight glass & hop filtre tube (metal) & tap - with gas burner placed underneath
Electric pump and hoses to transfer liquor and wort from vessel to vessel
Metal Heat Exchanger and hoses to cool wort before fermentation
Metal ladel for mixing GRIST and liquor
Plastic bucket for grist mixing
Plastic jug for recirculation of wort in Mash Tun
BRIX meter
Hydrometer & test tube

STERILISATION
Starsan mixture used to rinse and soak (5 mins) for all equipment.

BREWS
Typically 65 Litre brews (fermentation vessel). English and Americal IPAs, bitter etc. Ingredients Maris Otter, crystal and chocolate malts, torrified wheat, English hops, protofloc tablet, AMS & DWB water treatments, Safale 04 yeast.

Thank you
Could be anything post boil so I agree that you should oxi everything. But I'd imagine it's your FV. I had a similar issue with some brews I did years ago. I started brewing again this year with new equipment and some new plastic buckets and no issues.
Cheers and gone,

Mozza

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Re: Off taste after 4-6 weeks in Corni kegs

Post by Fil » Tue Jun 06, 2017 11:31 pm

as above .. paying special attention to everything cold side.. strip the kegs down for a deep clean of everything, down to pulling poppets carefully from inside the posts as that is the 'bottleneck' and use a pressure cooker to get upto 130c at 15psi for a lab grade heat sterilisation which is more effective than chemical sanitation..

if you cant fit your hex in a pressure cooker consider baking it in the oven for a heat treatment guaranteed to sanitise hit 130c..

And if its something thats got into your dispense system, i would suggest pulling/replacing all the beerline and perhaps gas too, (its cheap enough) as well as giving taps and jg fittings a good clean and bleach soak (i dont think they will take 130c in a pressure cooker if you have spares it might be worth sacrificing 1 to test?)

Also Check up on this and dont rely on me as gospel but afaik Starsan isnt effective against yeasts, and souring could be a wild yeast infection PAA is the no rinse sanitiser used in the dairy industry which is more effective against wild yeast strains than starsan, if its a wild yeast thats found a home elsewhere and is releasing spores in your breweries direction all the sanitation in the world relying on starsan could be ineffective. PAA isnt very expensive but will deteriorate giving off a vinegar aroma as it does, and if sprayed take more care to avoid the eyes and breathing in the vapour..
ist update for months n months..
Fermnting: not a lot..
Conditioning: nowt
Maturing: Challenger smash, and a kit lager
Drinking: dry one minikeg left in the store
Coming Soon Lots planned for the near future nowt for the immediate :(

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Re: Off taste after 4-6 weeks in Corni kegs

Post by Jocky » Wed Jun 07, 2017 7:30 am

Your mash tun also being a fermenter absolutely screams out at me as the problem here.

Grain is covered in lactobacillus and a mash never gets hot enough to kill it - it's a great big bacteria soup. Starsan is effective, but there's always nooks and crannies for bacteria to hide in, and with the amount of it in the mash it's going to miss something.

Use a separate fermenter that you can keep clean and sanitary, keeping it away from grain or other infection sources. If you must use one of your vessels then use your boiler - you will have got it boiling hot for an hour, which is a good way of sanitising, but honestly a £10 plastic bucket is going to be way better than using your mash tun.
Ingredients: Water, Barley, Hops, Yeast, Seaweed, Blood, Sweat, The swim bladder of a sturgeon, My enemies tears, Scenes of mild peril, An otter's handbag and Riboflavin.

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Re: Off taste after 4-6 weeks in Corni kegs

Post by Haydnexport » Wed Jun 07, 2017 1:21 pm

Oh, wow I missed that jocky! I'd be pointing the finger at your mash tun / fermented then!

Fil
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Re: Off taste after 4-6 weeks in Corni kegs

Post by Fil » Wed Jun 07, 2017 5:23 pm

me too, now you bring it to my attention it sticks out like a sore thumb!!

sight glass in the tun too YUK!! i would stop that practice asap, plastic buckets are cheap as chips compared to the waste of a whole batch!!

As an aside.. in my own experience buckets between brews can present a way too tempting storage solution, and i have retired way too many brew buckets to gardening/waste collection duties due to the odd scratch down to careless storage of items within, Consequently i switched to the 4" neck wine fermentors the smaller neck prohibits easy storage of items within but is still big enough to get an arm in to help clean..
ist update for months n months..
Fermnting: not a lot..
Conditioning: nowt
Maturing: Challenger smash, and a kit lager
Drinking: dry one minikeg left in the store
Coming Soon Lots planned for the near future nowt for the immediate :(

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Jocky
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Re: Off taste after 4-6 weeks in Corni kegs

Post by Jocky » Thu Jun 08, 2017 9:12 am

Fil wrote:me too, now you bring it to my attention it sticks out like a sore thumb!!

sight glass in the tun too YUK!! i would stop that practice asap, plastic buckets are cheap as chips compared to the waste of a whole batch!!

As an aside.. in my own experience buckets between brews can present a way too tempting storage solution, and i have retired way too many brew buckets to gardening/waste collection duties due to the odd scratch down to careless storage of items within, Consequently i switched to the 4" neck wine fermentors the smaller neck prohibits easy storage of items within but is still big enough to get an arm in to help clean..
My preferred fermenters are the Speidel HDPE ones. They seal up air tight, are smooth on the inside, and have strong handles for carrying. Cost a few more quid than a plastic bucket, but worth the extra IMHO.

But anything is better than using a mash tun. No practical way you can sanitise a sight glass, tap etc
Ingredients: Water, Barley, Hops, Yeast, Seaweed, Blood, Sweat, The swim bladder of a sturgeon, My enemies tears, Scenes of mild peril, An otter's handbag and Riboflavin.

JCU

Re: Off taste after 4-6 weeks in Corni kegs

Post by JCU » Wed Jun 14, 2017 7:06 pm

Thanks everyone. I'm using fresh dried yeast every brew. Safale 04 mostly.
And from now on will use dedicated fermentation vessels without sight glasses or taps. Just a stock pot and lid.

Another possibility came to mind. I rack the beer immediately after the fermentation has reached the desired Final Gravity into 3 x 18.9L corni kegs, e.g. 1.010 or 1.012. Could this be causing the sourness by diacetyl being present in the beer? Do I need to perform a diacetly rest?

Thanks

Fil
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Re: Off taste after 4-6 weeks in Corni kegs

Post by Fil » Wed Jun 14, 2017 9:05 pm

afaik the diactyl flavours (no i can never spell it..) are 'thick oily' buterscotchy rather than sour, sour 'smells' more of a lactobacillus or wild vinegar yeast and my gut suggests the nooks and corners of the sight glass tube and its plumbing and its probable cooler than the mash temperature is the most likely suspect, but a near close to ocd approach to a thorough clean up and the change in habits already committed to should sort you out

some diactyle content can be of beneft with more complex malty flavoured brews, and unless having a noticeable issue or aiming for a dry clean lightly malted flavour in the final result, it may not be worth it.
ist update for months n months..
Fermnting: not a lot..
Conditioning: nowt
Maturing: Challenger smash, and a kit lager
Drinking: dry one minikeg left in the store
Coming Soon Lots planned for the near future nowt for the immediate :(

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Jocky
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Re: Off taste after 4-6 weeks in Corni kegs

Post by Jocky » Thu Jun 15, 2017 9:04 am

JCU wrote:Thanks everyone. I'm using fresh dried yeast every brew. Safale 04 mostly.
And from now on will use dedicated fermentation vessels without sight glasses or taps. Just a stock pot and lid.

Another possibility came to mind. I rack the beer immediately after the fermentation has reached the desired Final Gravity into 3 x 18.9L corni kegs, e.g. 1.010 or 1.012. Could this be causing the sourness by diacetyl being present in the beer? Do I need to perform a diacetly rest?

Thanks
Diacetyl isn't sour - it's like butterscotch.

Sourness only comes from bacterial infection (lactobacillus, acetobacter), or massively extreme oxidation (i.e. leave the beer in an open bucket for several weeks - ethanol oxidises to acetalaldehyde which oxidises to acetic acid).
Ingredients: Water, Barley, Hops, Yeast, Seaweed, Blood, Sweat, The swim bladder of a sturgeon, My enemies tears, Scenes of mild peril, An otter's handbag and Riboflavin.

JCU

Re: Off taste after 4-6 weeks in Corni kegs

Post by JCU » Mon Nov 06, 2017 5:07 pm

Thanks everyone, this seems to have worked.
One other question; how can I brush out, thoroughly clean the heat exchanger (sealed unit) and metal coiled pipe (5mm in diameter - 2 metres in length).

Thanks,
JCU

FermentedCulture

Re: Off taste after 4-6 weeks in Corni kegs

Post by FermentedCulture » Mon Nov 06, 2017 6:39 pm

It's a possibility that it was the S-04 yeast that produced this flavour because it makes lactic acid. Apparently ncyc 1026 is the same as whitbread b which is s-04.

https://catalogue.ncyc.co.uk/saccharomy ... isiae-1026 (strain information: high lactic).

There have been posts on other forums about this yeast developing sour notes over time like with your original post so it could just be it is more pronounced as the flavour profile changes. Reviews I've read usually lead to descriptions of: twang, yoghurty, tart, sour.

While I personally wouldn't ferment in the mashtun, I would have thought that the temperatures it is heated to in the mash tun would be enough to pasteurise it (hence stuff like "raw ale")? You could probably work out how much pasteurisation occurs by inputting your mashing regime here: https://sizes.com/units/pasteurization_unit.htm

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Re: Off taste after 4-6 weeks in Corni kegs

Post by orlando » Tue Nov 07, 2017 1:08 pm

JCU wrote:
Mon Nov 06, 2017 5:07 pm
Thanks everyone, this seems to have worked.
One other question; how can I brush out, thoroughly clean the heat exchanger (sealed unit) and metal coiled pipe (5mm in diameter - 2 metres in length).
A dishwasher powerball tablet dissolved in about 5 litres of hot water and a 1/2 hour soak at least. Then flush like mad till the water runs clear. Might be worth repeating if you are horrified by the colour of the water coming out. Once you are happy it is clean, bake in the oven or pressure cook it for 20 mins at 15 p.s.i. Alternatively if you have some caustic soda crystals use these but ensure contact time is circa 1/2 hour only.
I am "The Little Red Brooster"

Fermenting:
Conditioning:
Drinking: Southwold Again,

Up Next: John Barleycorn (Barley Wine)
Planning: Winter drinking Beer

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