Persistent oxidised beer problem

[Seeker]

I have a persistent off flavour that's crept into my beers, two of which have been bad enough to tip away.

I thought it was an infection at first, but I now think it's oxidation (I'm putting the change down to my taste getting more refined). I can now detect a distinct wet cardboard taste. In most beers it's been very slight, but in two of them it was really bad.

It's co-ioncided with a number of changes which has made it very tough to track back, and I now think it's probably been there quite a while.

I'm making UK ales, with Maris otter + crystal, and hop pellets which are always frozen, but not shrink wrapped and can be up to 12 months old.


I BIAB with a 40ltr urn, then no chill into a Bunnings cube, either poured straight in or through a silicone tube, both showed the problem. The cubes I'm now using are hard to get all the air out so the last ones have had a fair bit in, and this seems like a possible cause.

I've then been chilling in a swimming pool - not going to do that any more as it's probably not required and adds risk.

Then ferment in the same cube or into a fermenter - both ways have show the problem.

The last two I did were a FWK and an IPA. My IPA is slightly funky, but the FWK was perfect, which leads me to thinking the problem is not post fermentation, as the only difference was I added gelatine to my IPA.

Both kegs were filled with sanitiser and then evacuated with CO2, filled with a hose then head space vented about 5 times.

I'm pretty sick of it and I really thought I'd have nailed it by vastly improving my kegging, but that's not been the case.

 

[Seeker]

Just to add - the reasons I don't think it's infection based;

No change to body.
Under carbed (flat) beers are just as bad.
Bottled beers have been as bad.
Everything else about the beer is fine.

 

[Topher]

Perhaps its changes to your water? FWK was probably made with filtered and treated water.

Have you changed your sanitiser?

Do you cold crash? Is your ferment temp controlled?

How much Crystal malt?

Im sure someone here can answer this better.

 

[Seeker]

Last few beers have been rain water - I was using filtered tap water before that. I think it's occurred with both, but is certainly there with rain water (all the last beers have been rain water or tap drip filtered through Britta clone filter - it is past it's best, but water was tasteless)

Sanitised with bleach then Star San, cleaned with Napisan.

The Napisan has changed a few times, and is the one with blue flecks in it, but fermenters have been bleached after cleaning. I have only recently started using bleach, and it MIGHT coincide.

I don't normally cold crash - temp controlled at 20c (FWK and my IPA both fermented at same time, same temp)

Crystal varies - 100 - 400g - 23ltr batch.

Been adding water treatments; Calcium sulphate & Epsom salts & occasionally PH buffer (not in rain water though).

 

[antiphile]

I'm not a no-chiller so give this post little credibility. If the cubes are being stored for any length of time without excluding all the air, I'd agree it's quite possible that is the problem. From my limited knowledge, I'd prefer to have the cube absolutely full before sealing it up and cooling it.

Hope you find the solution soon. Cheers

 

[Vini2ton]

I thought the whole no-chill idea worked on basic food preserving principles. If you have air in your cubes then it''s all wrong isn't it?

 

[wobbly]

If you think your issues may be associated with your water then you could/should have a read of this topic http://www.homebrewtalk.com/showthread.php?t=198460
Yes I know 121 pages are a lot to digest but there are some good sound advise contained therein.
AJ deLange and Martin Brungard are well qualified water chemists and co reviewed Palmer's book on water.

Cheers

Wobbly

 

[NealK]

A couple of things I would try:
Stop using bleach, starsan will sanitise very well after stuff has been cleaned with sodium perc (or napisan)
When filling your cube use a silicon hose and try to eliminate all splashing. I have found that opening the tap just over half way not only helps with this but also helps keep the trub in a nice cone.
Other things to consider:
How many taps do you have? When were they last stripped and cleaned?
Have you been regularly stripping and cleaning the posts etc. of your kegs?
When filling your kegs are you getting any splashing?
Do you use gladwrap or a lid and airlock?
Do you cold crash before kegging?

 

[Seeker]

How many taps do you have? When were they last stripped and cleaned?

Single picnic tap - stripped every time.

Have you been regularly stripping and cleaning the posts etc. of your kegs?

Yes, every time.

When filling your kegs are you getting any splashing?

Yes I am getting some, but flushed the last one with CO2 before filling, also the FWK got splashed much worse as I made a mistake, and that was not affected.

Do you use gladwrap or a lid and airlock?

Gladwrap or a cube lid. Actually I think all the affected beers have been jerry cans with lids loosely fitted. I also think they may all have been no chilled or fermented in those blue Bunnings jerry cans. I was using the white ones, but broke a few. The blue cans have probably been used for no-chilling and/or fermenting every problem beer. The FWK was fermented in the cube it came in.
I have noticed that the blue cubes smell when you add Star San ( a bit sulphureus). I wonder if they could be reacting with heat or chemicals!?

Do you cold crash before kegging?

Not usually no. The current affected beer was kegged and then chilled to around 3-4c and gelatin added, but I usually only chill to around 8c.


I'll drop the bleaching and squeeze all air out next brew, and maybe drop the blue cans too.

 

[Reman]

Bleach has to be thouroughly rinsed or you will get off flavours, I'm sure you can guess how I know.

 

[Seeker]

They get well rinsed, but how to tell it's all off?
Also they may get left for a month soaking in bleach.

 

[manticle]

How are you rinsing that bleach?

 

[Spiesy]

I've never had cubes or fermenters smell sulphurous, maybe like hops or malt, but not like yeast by-products. Get some PBW and boiling water in there, and use a fermenter for a fermenter, man! Much easier to clean.

 

[manticle]

Cubes are easy to clean too.

 

[Seeker]

Rinsing with water until run off doesn't smell or feel slimy.

I can get a Jerry can and fermenter in my fermentation freezer.

Unless I'm doing 25ltr I use a Jerry can normally.

Smell is very chemically when star San is added. Maybe something getting freed by the acid?

 

[manticle]

If you really need to use bleach, rinse well with boiling water and/or sodium met solution.
Not saying this is the cause of the issue but leaving bleach in fermenters for a month then just rinsing is not a great idea.

 

[Jack of all biers]

I BIAB with a 40ltr urn, then no chill into a Bunnings cube, either poured straight in or through a silicone tube, both showed the problem. The cubes I'm now using are hard to get all the air out so the last ones have had a fair bit in, and this seems like a possible cause.

I don't no-chill, but I think if you are fairly positive it is oxidation you are tasting then I think your above description of transfering your hot wort to your cube is the likely cause. Too much carelessness when dealing with hot wort and splashing or exposing it to large surface areas of air is a big problem.

To reduce oxidation in hot wort never pour. If you have stopped doing this by using a silicone tube, maybe have a look/think about how you have done it in the past. Have you ensured the tube is at the bottom of the cube? Have you ensured that the pour is slow until the outlet of the tube is well covered (at least 2 inches)? Have you ensured that there is no sucking of air into the tube and that it fills with wort once the tube outlet is covered? Lastly, (as has been expressed by others already) leaving air in the cube is inviting some oxidation in your still hot wort. I would keep these air exposing factors to a minimum in your next brew and see if this improves things.

If you are absolutely sure you have reduced all oxidation exposures (and I mean be thorough in your examination of your methods) then maybe think about improving your fermentation/yeast management/conditioning procedures.

This is because Aldehyde (Trans-2-nonenal) will have a cardboard/papery flavour and has an extremely low taste threshold. It could be produced by poor yeast management/health/highly flocculent strains/use of finings prior to full attentuation, insufficient conditioning time, bacterial infection and more. Good sanitation, good pitching rates, using healthy yeast and allowing proper fermentation and conditioning times would over come this problem. I suggest this would be an unlikely cause to your issue, because if you are having problems with the cardboard flavour then you would also have other green beer type flavours. I only mention it as another slight possiblity to consider after you have completely eliminated oxidation which is the likely cause.

 

[Jack of all biers]

When filling your kegs are you getting any splashing?

Yes I am getting some, but flushed the last one with CO2 before filling, also the FWK got splashed much worse as I made a mistake, and that was not affected.

Do you use gladwrap or a lid and airlock?

Gladwrap or a cube lid. Actually I think all the affected beers have been jerry cans with lids loosely fitted. I also think they may all have been no chilled or fermented in those blue Bunnings jerry cans. I was using the white ones, but broke a few. The blue cans have probably been used for no-chilling and/or fermenting every problem beer. The FWK was fermented in the cube it came in.
I have noticed that the blue cubes smell when you add Star San ( a bit sulphureus). I wonder if they could be reacting with heat or chemicals!?

For some reason, prior to my last post the above post and those after it were not visible to me. Umm... I think you have stated your oxidation problems in both the splashing and in loose fitting lids. Not ideal. Also check the underneath of the blue bunnings jerry cans to see what type of plastic they are. If a 2 and triangle symbol or HDPA they should be ok as far at the type of plastic goes, but if you can get any sucking of air in or out then you need to use cubes that don't do that.

 

[Spiesy]

Cubes are easy to clean too.

Not as easy. You can't just get your hand in there to give them a wipe.

 

[dicko]

As it has been said, splashing hot wort will cause oxidation
Just on a side note, stale hops that are poorly stored can offer many strabge flavours to the finished beer.

Handle hot wort very carefully and go and buy some new hops that are supplied in nitrogen filled packs from a reputable hbs.

One other thing...how long are you boiling for?
Boiling drives o2 from wort

Good luck with it

 

[Seeker]

Boil is for 90 minutes with 15-20 rest after flame out.

Interesting about hot transfer splashing. I'd read somewhere that it's not a problem due to near boiling liquid not absorbing oxygen.

I'll avoid from now on, thanks

 

[dicko]

When I no chill I inject a bit of Co2 into the bottom of the cube and transfer wort through a silicon hose.
I also run the wort very slowly for the first few litres and tilt the cube towards the hose end so as the wort coming into the cube is discharging under the surface as soon as is possible.

 

[TheWiggman]

I used to splash my hot wort into the fermenter on my first few brews because I thought I was doing the right thing, and I got a 'character' from the beer I'd rather not have that was similar to oxidation. Try avoiding any splashing on your next brew with a known recipe and see how you go.
As you said, the fact the FWK tasted fine and your brew didn't alludes to your ingredients or process being at fault.

 

[Seeker]

Thanks guys.

I might actually kettle chill the next one to rule out any possibility of oxidation during transfer - I need it straight in a fermenter anyway.

 

[manticle]

Not as easy. You can't just get your hand in there to give them a wipe.

I won't say one is easier than the other but if you rinse your cube immediately on emptying then put enough boiling percarb solution in so that the krausen ring is submerged when the cube is upside down, you have no need to scrub/wipe. Usually 2-3 litres and a quick shake does it for me but you can turn it upside down and just leave for a few hours or overnight if not in a rush. If you're one of those people who leaves their fermenting vessel to develop krausen crust then it becomes more difficult (not impossible).

 

[Nick667]

I used to splash my hot wort into the fermenter on my first few brews because I thought I was doing the right thing, and I got a 'character' from the beer I'd rather not have that was similar to oxidation. Try avoiding any splashing on your next brew with a known recipe and see how you go.
As you said, the fact the FWK tasted fine and your brew didn't alludes to your ingredients or process being at fault.

You did well.
I didn't figure it out for years. Just recently in fact.
Palmers online book has it hiding there under 'Metallic' in off flavours. Aerating over 26C is a no no.
I thought I was doing the right thing as well.
There must be hundreds of home brewers falling for the trap and getting that nasty homebrew taste.
I all grain now but when I used to kit and kilo I, and most others, would throw that water in there.

 

[Jack of all biers]

Palmers online book has it hiding there under 'Metallic' in off flavours. Aerating over 26C is a no no.

Read again. From Palmers 'online book' under the chapter 7 'Boiling and cooling'

'7.4 Cooling the Wort

At the end of the boil, it is important to cool the wort quickly. While it is still hot, (above 140°F) bacteria and wild yeasts are inhibited. But it is very susceptible to oxidation damage as it cools.'

And in the next paragraph;

'Minimize splashing to avoid oxidation.'


EDIT - Okay, now you can call me finicky. The only reference to metallic in off flavours (or anywhere else) in Palmers brew manual is in reference to metal oxides, not oxidation. Huge difference.

 

[Jack of all biers]

I'd read somewhere that it's not a problem due to near boiling liquid not absorbing oxygen.

This is kind of right in that O2 (oxygen) won't absorb into the liquid via suspension. However the oxygen molecules are easily bonded to other chains at the high temperatures of the hot wort and form various oxide chains (which is the process of oxidation). These oxide chains can later break down chemically and thereby cause the off flavours and other problems (ie staling of the beer).

The difference between O2 suspension (aeration) and oxidation (O2 spliting to form oxides with other molecule chains) is the misunderstanding here.

P.S. for the chemists out there, please excuse my laymans description/understanding of the oxidation process.

 

[michaeld16]

Not as easy. You can't just get your hand in there to give them a wipe.

I like to avoid any physical wiping of plastic just wiping your hands along plastic will scratch it, hot pbw will remove most krausen gunk in little time, or just cold napisan as I use most of the time will remove the crud in a day or to.

 

[Kev R]

If you are using bleach you should not be rinsing with starsan. Rinse the bleach with lots of water then use starsan. Starsan is an acid and bleach is a chlorine think it makes chlorine gas, used to kill troops in ww1. May also leave some in your brew (chlorine not troops)