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Mysterious color change in bottled beer

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Darth_Morris

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Hey everyone!

I've been brewing beer for some time now and have come across a very strange issue. At first I thought it was an oxidation problem, but after being incredibly careful with my racking and bottling, I am starting to think it may be something else. Now, I am not saying my bottling is perfect -- I usually have to stir in the sugar mix (I deal wit large volumes - around 40Gal -- but there is always some variation, so I have to measure the beer volume before adding the sugar solution), and our bottling method uses a machine called enolmatic vacuum filler that essentially sucks up all air from bottles and replaces it with beer. It is not perfect, like I said, but we don't have the means to use CO2 to purge lines and fill bottles yet. This had all been working fine though.

Some of our batches have been bottled looking a nice golden color, characteristic of the Belgian blond we were brewing. Then though, after popping a bottle open after a couple of weeks in conditioning, they have been coming out darker than normal.

Pinpointing the problem has proved super hard because when tasting the beer, I cannot detect any cardboard taste whatsoever. In fact, I think it doesn't taste bad, it is just not what I brewed. The hop character is close to all gone

I was wondering if anyone had any input on this. I've been wondering if this could be caused by any of the following:

1. Improperly sealing bottles (our bench capper wasn't working so great: a recently bought go-no-go gauge told us that). We have since moved on to a different bottle capper that seems to be exactly what we needed.

2. Oxidation from over stirring of priming sugar (I find this improbable as I am very careful with this). I give it a few swirls and make sure not to bubble or raise any liquid from the pot.

3. Maybe it is actually an infection from wild yeast. However I am wondering how this would be the case since I always clean everything with 0.3% Peracetic acid (they don't sell Starzan where I live). Bottles are also left in 0.3% PAA solution prior to bottling to make sure they are sanitary.

Any help to pinpoint this problem will be awesome. I am attaching a couple of pictures to this post: left golden glass contains the beer as it should look, the other one looks browner. Also, I have obtained a few other batches that looked even darker than this one in the glass.

** Please note that the golden beer was bottled 3 days ago so the difference in carbonation is due to it not being fully carbonated yet. I popped it open to look at it and see if anything had changed. The darker beer is about 3 weeks old since bottling


IMG_5657.JPG IMG_5656.JPG
 

Smellyglove

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Oxidization does not have to taste cardboard. When it tastes like cardboard its just a sign of severe oxidization. First steps of oxidization is loss of flavor and aroma, and then darkening of the beer..

Not saying that it is oxidization, but you're at least describing oxidization.
 
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Darth_Morris

Darth_Morris

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Holy fast response! Haha thanks Smellyglove.

I had never had any problems with oxidation before so I wasn't sure it was the culprit. You are correct though. Through a ton of reading I have found out that oxidation has multiple stages. However it has struck me as odd that I haven't detected any strong off flavors other than the lack of hops.

Another person with brewing experience told me a few weeks ago that to him all of this looked like a case of wild yeast infection, which threw me in for a spin. I did some research and found that wild yeast can indeed have some of the same effects that I am seeing here (change in color and aroma). What I haven't seen much of though is gushers. From what I understand, I should expect a few bottles to either explode or gush out at the moment I pop them open. This really hasn't happened. I am still to discard the infection though --I need to compare the FG of bottled -- but at this point I lean away from it (but not fully abandon the idea).
 
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Darth_Morris

Darth_Morris

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*** UPDATE:

I checked the FG of both beers and they are both about the same. This leads me to believe that there is no infection.

Could improperly sealed bottle caps cause oxidation while keeping gas in? Seems like it wouldn't make any sense but it is the one thing I have found to be inconsistent across batches.
 

PlinyTheMiddleAged

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Darth,

That sure sounds like oxidation. As Smelly says, cardboard doesn’t describe mild oxidation effects. I’m a big fan of IPAs but I could never brew a good one that last more than 1-2 weeks in a keg. Hop flavor would quickly fade, malt flavor would start to sweeten, and the beer would start to get dark. Sounds and looks like what you’ve got going on.

I started adding sugar directly to the fermenter and waiting for fermentation to restart (about an hour or so) and then package directly from the fermenter (no need to stir - the yeast will take care of that for the most part). With active yeast to protect against oxygen, you might have some better experience. The downside is you might get a bit more yeast on the bottom of the bottle.

PlinyTheMiddleAged
 
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Darth_Morris

Darth_Morris

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Hi Pliny,

I’ve heard that IPAs are particulrly suceptible to oxidation issues and that if you plan to dry hop then you better brace yourself because its very easy to oxidate beer in this way. I currently have an IPA finishing fermentation in a galon container so I hope all is well with that one.

That idea about the fermenter sounds like a good one. I did try something like that at one point but the sugar solution didn’t seem to mix homogenously in the FV and I ended up with bottles with either no carbonation or lots of it. Maybe I should give it another go at some point.
 

ESBrewer

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I suspect that it is sedimentation of particles (mainly yeast but also protein and haze complexes) combined with some oxidation. Is there a lot of sediment in the bottles after 3 wks? It seems obvious from the pictures that the darker beer is much more transparent in nature indicating that a lot of material has dropped during 3 wks. This will darken the color a lot. But there is probably some degree of oxidation as well, especially if you mean that the aroma of the hops has faded and because the color change is so substantial. Is this pilsner malt and light colored wheat only? Some amount of aromatic malt that brings deeper color?
 
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day_trippr

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It's oxidation. And the home brewing world should rue the moment some nitwit forever related "oxidized beer" character with "cardboard" and "sherry", as the much more subtle tell-tale off-notes begin waaaay before those come to pass...

Cheers!
 
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Darth_Morris

Darth_Morris

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I suspect that it is sedimentation of particles (mainly yeast but also protein and haze complexes) combined with some oxidation. Is there a lot of sediment in the bottles after 3 wks? It seems obvious from the pictures that the darker beer is much more transparent in nature indicating that a lot of material has dropped during 3 wks. This will darken the color a lot. But there is probably some degree of oxidation as well, especially if you mean that the aroma of the hops has faded and because the color change is so substantial. Is this pilsner malt and light colored wheat only? Some amount of aromatic malt that brings deeper color?
Right, the 3 week old bottle is definitely clearer because of the yeast and other stuff dropping out. However I have observed good batches after 3 -5 weeks in a bottle and they drop clear AND appear golden in color. So I rule out its any kind of suspended sediment.

The recipe is mostly pilsner malt, with some pale ale in there and a TOUCH of carahell and caraAroma. By touch I mean an almost negligible amount (about 1% of total weight each of those).

It's oxidation. And the home brewing world should rue the moment some nitwit forever related "oxidized beer" character with "cardboard" and "sherry", as the much more subtle tell-tale off-notes begin waaaay before those come to pass...

Cheers!
thanks day_trippr! I think you and everyone else might be right here. No change in FG and stale flavors seem to pinpoint to oxidation. I am just at a loss as to why it is happening now as opposed to before. The last few batches shave all come out brownish and it makes no sense. The whole bottling technique is the same as at the beginning.
 
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Darth_Morris

Darth_Morris

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Hey everyone,

So, going back to the oxidation issue, I was hoping I could get some more help. I am having lots of trouble pinpointing the source of oxidation. Any ideas might help. Here's a quick run down of how I bottle and a few points that I think are the interesting ones to figuring out the problem. Sorry for the long read:

Racking Process
I plug a sanitary hose to the racking tube on my FV. Everything to this point has been either sanitized using 0.3% PAA or, in the case of connections, sprayed with Starzan solution (I managed to bring some back from the states last time I was there).

Sanitary hose from FV goes to a chugger pump, and then another hose goes from the pump to a large stainless steel pot I have. The hose connects to a valve on the lower side of the pot.

Afterwards, I rack by opening the valve on the FV and the one on the pot. I don't switch on the pump yet so I don't agitate the beer flowing at the beginning and going into the pot. I let gravity do its work, and then when I see that gravity is no longer helping, I switch on the pump and fill the pot with around 120L (~31gal) of beer, ready to be primed with sugar.

I make the sugar solution using boiled water and then add it, slowly, to the beer in the pot. Then I give it a few gentle swirls to make sure the sugar mixes well, and then proceed to start bottling. This is done through a tube I connect to the valve on the lower side of the pot (the one that previously had the chugger pump attached). Tube goes from the pot towards the enolmatic bottle filler. Then I just start filling to my hearts contempt.

Filling Process
Every bottle is filled by the vacuum pump extracting air from the bottle and causing a pressure difference that fills the bottle with beer. Now, here is one of the points I wonder if its an issue or not (like I said, we've had good batches that have kept well for over 2 months bottling this way): the bottle is filled from around the top. There is a vacuum seal on the bottle, which allows the air to be removed and replaced with beer, but there has to be some contact with air, right? And the splashing has got to do something. We've had good batches though.

Bottles are then promptly capped and stored in boxes away from sunlight.

Points of Interest
1. Hot side aeration during mash: This to me seems highly improbable (and I feel like I am opening a can of worms mentioning it), but I thought I should bring it up. From what I understand, HSA occurs only at large scale breweries, nothing like the sorts of what I am doing. My mash volume is around 160L. I do add water first and then the grains on top because it is just more streamlined for me in that way. After that I mix using a large spatula and let the mash do its thing. First runnings are collected in a 5gal bucket and then added back to the top of the mash. There is some splashing.

2. HSA during cooling: After the temperature of the wort is dropped, I send the beer to the fermenter. At this point, I let it splash inside the FV since I am trying to aerate it. The temperature is usually in the 30s (celsius - like 90s F). It is very hard to cool it down more than this because the weather is so hot right now.

3. During transfer to bottling bucket: A sight glass is attached to the FV's racking tube and I check there if there is any air in the line. As soon as I open all valves, the beer pours out with some force and bubbles do end up here and there, but they are gone quite shortly after that.

4. Swirling motion when adding sugar solution. Could this be causing a problem? It is very gentle.

5. During bottling: The large volume of beer and single spout on the enolmatic means we bottle for a LONG time. Usually around 3-4 hours. I know this is a pretty long time for bottling, but like I mentioned before, we didn't have issues at the beginning. The pot's lid is kept on the whole time to prevent infections and try to keep the CO2 in.

Sorry for the long post guys, I'm trying to get all this sorted out before I bottle again and mess up another batch. Never had this problem when doing 5gal batches.

Cheers!
:mug:
 

Jwood

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Have you ruled out the chugger pump transfer from FV? I would suspect that isnt a very "gentle" or low agitation/O2 process, but i could be wrong.
 
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Darth_Morris

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Have you ruled out the chugger pump transfer from FV? I would suspect that isnt a very "gentle" or low agitation/O2 process, but i could be wrong.
Hi J! I can’t say I can rule it out completely but I think it is an unlikely culprit. The batches that came out first were all completely fine and were much more agitated by the pump since I was still getting the hang of our brewing process.

Something tjat came to mind though is that we recently had a giant heat wave and I think this may have affected the bottles during priming. They were sitting at RT somewhere around 22-27C (~70-80F) and when the heat started the temperature went up to 30-40C (~86-104F). Could this have caused an increase in oxidation rate or stressed out the yeast enough to change the beer’s character? Yeast packet says I shouldnt let temp rise above 20C. Obviously RT is on the warmer side of the range where I would like to keep my bottles priming but it’s all we can manage right now
 

Jwood

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Hi J! I can’t say I can rule it out completely but I think it is an unlikely culprit. The batches that came out first were all completely fine and were much more agitated by the pump since I was still getting the hang of our brewing process.

Something tjat came to mind though is that we recently had a giant heat wave and I think this may have affected the bottles during priming. They were sitting at RT somewhere around 22-27C (~70-80F) and when the heat started the temperature went up to 30-40C (~86-104F). Could this have caused an increase in oxidation rate or stressed out the yeast enough to change the beer’s character? Yeast packet says I shouldnt let temp rise above 20C. Obviously RT is on the warmer side of the range where I would like to keep my bottles priming but it’s all we can manage right now
The effects of oxidation are definitely accelerated at higher temperatures, but it doesnt explain why the oxidation is occuring in the first place unfortunately.

You say it has been fine before but on the latest couple beers it is an issue. Does it seem style or recipe dependent? See the link below for an example of how quickly the appearance can change of a NEIPA and the effect of just bottling vs kegging and O2 on appearance.

http://brulosophy.com/2018/03/12/th...oning-on-new-england-ipa-exbeeriment-results/
 
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Darth_Morris

Darth_Morris

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The effects of oxidation are definitely accelerated at higher temperatures, but it doesnt explain why the oxidation is occuring in the first place unfortunately.
right! I am sure oxidation occurs in my beer. I don't use CO2 at any point in my tubing or bottling system. The beer is racked onto a large pot and then immediately is bottled. Therefore there IS contact with oxygen, which I thought might definitely cause oxidation. Then, I thought that perhaps the exposure to air + the high temperatures during priming could result in an acceleration of the beer turning color and flavor dulling out.

You say it has been fine before but on the latest couple beers it is an issue. Does it seem style or recipe dependent? See the link below for an example of how quickly the appearance can change of a NEIPA and the effect of just bottling vs kegging and O2 on appearance.
It seems to be style and recipe independent. I've only brewed the one kind of beer and it was doing great at first and then it kind of just stopped coming out right. No change anywhere in the recipe nor brewing technique.

**EDIT:
J, I saw the link you posted up there. I love that site, its full of little tips and experiments that try to answer most questions I've had. Anyway, the particular page you sent me shows almost exactly what I witness with my beers, except mine is a Belgian Blond and it is only bottle conditioned. The color change is almost exact, but in my case much more accelerated. This is weird because from what I understand, the higher your hop utilization, the higher your rate of oxidation will be. My recipe only has about 17 IBUs. Also, if I leave one of the "good" beers out for around 12 hours, it turns brown.
 
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Darthbrewder

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Has your water profile changed? Could you be getting some excess copper, iron or manganese in your water, wort or beer?

I know these metals are oxidizers. It could be possible that your water had changed, maybe.
 
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Darth_Morris

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Ah, a fellow Darth!

Has your water profile changed? Could you be getting some excess copper, iron or manganese in your water, wort or beer?

I know these metals are oxidizers. It could be possible that your water had changed, maybe.
I am actually going to be running some tests this week on the water supply using a kit I have from LaMotte. I have a hunch this might not be the issue though.

What I am wondering is if hot side aeration might have anything to do. Since I didn't have a stone I could use to oxygenate the beer in the fermenter, I resorted to good ol' fashioned wort splashing. Since it has been summer here and the temperatures have been extremely hot, I had a very hard time bringing the temperature of the wort below 30C using immersion coils, so what I did was just throw the wort into the fermenter using a chugger pump and a sanitized hose. This would create lots of splashing, aerating the wort nicely, and then the chiller attached to the fermenter would take care of the temperature difference and cool down the wort to pitching temperature (18C).

I didn't believe too much in HSA, but this might be one of the things I did change from the beginning, when I was trying to do everything by the letter. Anyone ever had any issues with this? I've read temperature needs to go below 26C to ensure HSA won't happen. Also, does the fact that staling reactions appear noticeable after a couple of weeks in bottle help pinpoint the problem?
 

Darthbrewder

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Any update on this? I am quite curious to find out if you found out where your problem is coming from.
 

ncbrewer

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Filling Process
Every bottle is filled by the vacuum pump extracting air from the bottle and causing a pressure difference that fills the bottle with beer. Now, here is one of the points I wonder if its an issue or not (like I said, we've had good batches that have kept well for over 2 months bottling this way): the bottle is filled from around the top. There is a vacuum seal on the bottle, which allows the air to be removed and replaced with beer, but there has to be some contact with air, right? And the splashing has got to do something. We've had good batches though.
I think the bottle filling is the most likely culprit, and your heat wave is making things worse.
 
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Darth_Morris

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Hey guys,

Well I ended up ditching the enolmatic and moving over to bottling using a bottling wand. It’s not the best solution but it seems to be working better, fingers crossed. I am using that until an order I placed for a proper CO2 4 head bottle filler arrives
 
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