Why is my beer getting darker with age?

[jwelch1103]

Even with an airlock on, the Ideal Gas Law applies, and if there was headspace in the carboy- oxidation is likely.

I know people who aren't scientists talk about the 'co2 blanket' that magically covers the beer- but it is a myth. The laws of physics still apply. Long term in a carboy is fine- but it must have 0 headspace and even then small amounts of oxidation occur. Oxygen even comes through the water (or other liquid) in the airlock, and the airlocks themselves allow air in, as do the bungs. Read the results of this study, geared towards Better Bottles, but this part is about the bungs/closures and oxygen uptake: http://www.mocon.com/pdf/optech/Closures - Oxygen Passage Study.pdf

Winemakers do age long term in a carboy, but they use antioxidants at racking, as well as employ techniques like 0 headspace in carboys.

Huh, who'd of thunk?
Very interesting data!

 

[rjstew]

Even with an airlock on, the Ideal Gas Law applies, and if there was headspace in the carboy- oxidation is likely.

I know people who aren't scientists talk about the 'co2 blanket' that magically covers the beer- but it is a myth. The laws of physics still apply. Long term in a carboy is fine- but it must have 0 headspace and even then small amounts of oxidation occur. Oxygen even comes through the water (or other liquid) in the airlock, and the airlocks themselves allow air in, as do the bungs. Read the results of this study, geared towards Better Bottles, but this part is about the bungs/closures and oxygen uptake: http://www.mocon.com/pdf/optech/Closures - Oxygen Passage Study.pdf

Winemakers do age long term in a carboy, but they use antioxidants at racking, as well as employ techniques like 0 headspace in carboys.

I'm not talking about long term storage, the beer was much darker 5 weeks after I put in the fermenter. I would think everyone's beer would be oxidized if oxidation occured in such a short period of time.

 

[boydster]

Are you sure it doesn't just look darker because the yeast is settling? Any beer will look a bit lighter while fermenting, from yeast in suspension reflecting light. Once the yeast settles, it looks darker, even darker than it will appear in a drinking glass, because the light has much further to travel through a carboy than a drinking glass.

 

[Yooper]

I'm not talking about long term storage, the beer was much darker 5 weeks after I put in the fermenter. I would think everyone's beer would be oxidized if oxidation occured in such a short period of time.

I think most beers I've judged in competition over the last 8 or so years HAVE shown signs of oxidation, actually. It's the most common flaw. It may not be severe in every case, of course, but it's present in most homebrews I've tasted from a bottle, especially if they are more than a few weeks old.

Anyway, if you're convinced it's not oxidation, then there must be someplace else to look. I just have no idea what that could be- beer doesn't darken without a cause. However, it could be that it just looks darker in a carboy once the beer has cleared and that is just appearance and it's not really darker. If it really is noticeably darker, darker than the wort was, then there is an issue.

 

[pfgonzo]

Yoop, thanks for linking that study. Was new to me, and quite fascinating.

 

[Pelican521]

Ok, well I'm brewing another IPA again tomorrow (gulp)... I went ahead and bought a kegging system and hoping for the best.

The recipe is very similar to the last IPA I brewed which tasted great at bottling time and then went downhill. Here's my plan which will hopefully reduce any oxidation issues:

Ferment for 2 weeks in primary and if FG is met I'll transfer to my keg. When I rack it, I'll pre-flush the keg with CO2. Not sure what the best way to do this is, I figure I'll hook up the gas on 10 psi and just burp it a bunch of times, unless there is a better way?

All my dry hopping will be done in the keg at room temp with the old dental floss trick which has the hop sack (leaf hops) hang about half way down in the keg. I'm going old school and ditching my auto siphon (I think it's the devil at this point) and just use my standard racking cane when I transfer. I'll flush it again with CO2 once the transfer is finished.

After 5 days I'll throw it in my fridge with some gas to carb up.

Then, hopefully, I'll be sending another post saying how amazing my brew came out

 

[freisste]

When I flush a keg, I just take my tank and open the valve with the outlet pointed into the keg. The adiabatic cooling of the CO2 makes it pretty dense compared to air. The whole keg is full of fog, so I call it good. Maybe not perfect.

Then I rack my beer in, always avoiding splashing. It pushes CO2 out the top. When finished, I close the keg and push in some CO2 through the post. I crack the seal to burp some out, then carb as usual in the kegerator. I've never noticed oxidation, although I'll admit that I'm not sure what to look/taste for in a mild case. My beer certainly doesn't taste like cardboard.

Good luck.

 

[Pelican521]

Thanks for the tip Freisste!

 

[Ski12568]

Now that I've read this, my last 3 batches and now my 4th that is in the secondary has had this problem. All extract brews, the NB Irish red kit, NB witbier, and a pale ale recipe.

I looked at my 2nd pale ale today and it's looking like an amber again.

I was also getting a cardboard off flavor in the first 2 batches but I blamed that on no fermentation temp control. The 3rd one I blamed on hot side oxidation from vigorously stirring my wort at the beginning of cooling.

Next time I'll try and not transfer to secondary. I also noticed a lot of head space in my 5 gal fermentor after transfer.

It's a bit discouraging but Im not going to be a quitter

 

[opiate82]

Now that I've read this, my last 3 batches and now my 4th that is in the secondary has had this problem. All extract brews, the NB Irish red kit, NB witbier, and a pale ale recipe.

I looked at my 2nd pale ale today and it's looking like an amber again.

I was also getting a cardboard off flavor in the first 2 batches but I blamed that on no fermentation temp control. The 3rd one I blamed on hot side oxidation from vigorously stirring my wort at the beginning of cooling.

Next time I'll try and not transfer to secondary. I also noticed a lot of head space in my 5 gal fermentor after transfer.

It's a bit discouraging but Im not going to be a quitter

Getting oxygen into your wort before pitching yeast is a good thing. The yeast need that oxygen at the start of fermentation. Your "hot side oxidation" is not causing your issues and if you don't have a good method to oxygenate your wort prior to pitching yeast, vigorous stirring is a good practice to get some in there.

 

[Ski12568]

I now wait to stir hard once the temp gets below 80F. I give the carboy a good shake too once it's to temp and in there. Before I was stiring hard during the boil and once I started cooling

 

[Ski12568]

http://www.howtobrew.com/section1/chapter6-9-3.html

 

[opiate82]

Go ahead and Google "Hot Side Aeration Myth." Basic consensus is that unless you need your beer to have a 6 month+ shelf life it is a non-issue at the homebrew level. One of those brewing boogy-men that has carried over from commercial practices that isn't really applicable to homebrewing practices.

Not saying that avoiding it isn't a bad idea (it can't hurt), but based on what you are describing I don't think hot side areation is your issue and you should look elsewhere in your processes.

 

[Ski12568]

I agree it isn't the issue, I still have the problem after changing my ways

 

[campbellmike]

I'm a novice but how much head space are you leaving in the bottles? I only bottled my first few batches but I used the bottling bucket with valve and minimum head space. I had zero color change and no oxidation that my taste buds could detect.

 

[Ski12568]

I leave about an inch in the bottles, it's the 5 gal carboy that has the large amount of headspace and that's also when the color changes. I'll post a pic of it in a bit

 

[Ski12568]

Here's what it looks like now. That's pellet hops floating at the top.

It's and APA recipe using extra pale liquid extract, cara-pils, crystal 10, and a little pale malt for specialty grains. Looked like a pale ale before transfer. I will not be transferring the next version

 

[unionrdr]

It's going to look darker in that carboy due to the width of the bottle. Get it in a glass & it should look a bit lighter.

 

[Ski12568]

Is that too much head space for a secondary? If so I need to add more water on my next brew, that's a 5 gal carboy

 

[unionrdr]

If the one in the pic is 5G, then you've got less than 4G in there.

 

[Ski12568]

Yeah, it's a 5gal

 

[unionrdr]

Fermenting a 5 gallon kit as less than that can add color & ABV. It can also get darker from boiling too much of the LME in the kit or recipe by maillard reactions.

 

[Ski12568]

It was a lot lighter when I transferred. I am going to take pictures with my notes at all stages from now on. I'll wait to see what it looks like in the glass. This happened to me with the NB witbier also. Looked like an amber

 

[Ski12568]

Seems as though I was over reacting with the color in secondary. This beer turned out great!


Still working on my carbonation, this is my first time kegging

 

[BrewinBromanite]

I've noticed the same thing on many batches. It often seems darker in the fermenter than in a glass. There's a lot more ability to have light pass through a 12 oz glass than a 5+ gal fermenter full of beer, which I'm assuming is the major culprit to the perception of increased darkness in the fermenter vs lighter final product in a glass.


Sent from my iPhone using Home Brew

 

[Pelican521]

Ok, since it's halloween, I thought I'd bring this thread back to life...

I've since decided to buy a kegging system and my hand again at an IPA that I brewed back in September to see if I could finally produce a decent IPA.

So right now I'm enjoying the best IPA (or any beer) that I've ever brewed. It's been kegged about 5 or 6 weeks and shows zero signs of oxidation. The flavor is crisp and clean with no muddy flavors and the color is exactly like when I racked it. The aroma and taste are very distinct of the hops I used unlike all my other bottled batches where they all tasted/smelled the same no matter which hops I used. Unlike all my other bottled IPA that suffered chill haze no matter how long I kept in the fridge, this is the clearest beer I've brewed.

It was also the easiest brew to date as I didn't secondary, and racked it at 12 days right to the keg (FG hit at 10 days). I dry hopped 3 oz of whole leaf in the keg in a muslin sack suspended by floss.

If anyone was in the same boat as I was with trying to brew an good IPA, kegging might be the solution!

Cheers!

 

[Vinbo7]

I think I found the real reason to your beer darkening in an earlier post in the thread here. It was happening at bottling time: you describe using oxi clean and then flushing that with Star San in your bottles. The earlier post described how if oxi clean isn't rinsed entirely then it reacts with the star San and causes the beer to darken.