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Color and taste over time

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smadaus

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So I made an IPA in November, bottled it two weeks before Christmas and it was ready to drink by Christmas. When I transferred the beer into the secondary it was a yellow color and very bitter and hoppy. When I opened the bottle at the end of December is was significantly darker but still tasted amazing. About a week or two later I noticed that the beer was even darker and the hop flavor was fading fast. It got really malty and the alcohol flavor is becoming present. I am not sure what is happening but does anyone have insight on this. Also is there something that you can add that helps with color and flavor retention. I know that over time beer changes but significant changes over two week periods seems like a lot. Let me know what you guys think. Thanks.
 
Darkening color, fading hops, and muddled/malty flavor are all classic signs of oxidation. It's basically a loss of freshness that you're experiencing. This phenomenon doesn't happen immediately, especially at cold temps, but rather progresses gradually until it's very evident.
 
Darkening color, fading hops, and muddled/malty flavor are all classic signs of oxidation. It's basically a loss of freshness that you're experiencing. This phenomenon doesn't happen immediately, especially at cold temps, but rather progresses gradually until it's very evident.
So the cure is... drink up fast?
Getting that oxidized in just a few months seems awful fast, doesn't it?
 
I'd say not really. It is what it is, unfortunately, and has no cure. I have a high ABV strong ale that I kept in secondary on oak for about 8 weeks before kegging. I tasted it maybe 3 times to judge its readiness by briefly opening the carboy and sampling with a wine thief. It was fine up til the very end. Now after a couple weeks on tap, it's going south in a similar way to what you describe. Such a bummer. There must have been too much headspace, and I opened the carboy too often. Lesson learned.

We do a ton of fear-mongering about infection, but I think oxidation is a far bigger risk to our product and harder to avoid given typical hombrewing practices.
 
I kept the beers at room temp until I was ready to drink it and then I throw one in the frig for a couple hours. Do you think the oxydation happened while in the bottles or through transfers and bottling?
 
There are solutions but they involve transferring from cylindroconicals against CO2 counter pressure and things like that so that they are not readily available to guys starting out with carboys and bottling buckets. Done properly beer will keep for over two years though I won't claim that there aren't some changes.
 
So the cure is... drink up fast?
Getting that oxidized in just a few months seems awful fast, doesn't it?

Not fast at all, actually. The number one flaw I pick up in beers I judge in competition is oxidation.

It is far too common, I'm afraid. Just racking the beer and packaging it combine to allow oxygen contact.

This beer we're talking about was made in November, so it's four months old. We laugh at it, but even commercial beers have packaging dates, or those "born on" dates so the beer has a definite shelf life. Commercial breweries avoid oxygen far more them homebrewers, but still have a recommendation to drink the beer fresh. They purge with c02, force carbonate with c02, push the beer with c02, etc- all in closed spaces to avoid oxygen. The beer is always protected from oxygen pick up.

Redhook Brewery showed me that they even clean their lines with low-dissolved oxygen water for their rinse (without any beer contact at all!) because oxygen is the scourge of beer.

Luckily, if we homebrewers drink our beer fresh, we can avoid most of the staling reactions. For beers aged long-term, like a barleywine, oxidation can actually be a pleasant part of the flavor profile (those nutty, sherry notes). We should do everythiing in our power to prevent oxygen pickup for beers we want to age a bit.
 
I've found that most of my beers taste *better* after at least six months.
That said, I brew a lot of dark malts and high-abv beers, so they need that time.
Also, to the extent that temperature matters, my cellar stays pretty cool: 45-55 in the winter, and 65-70 in the hottest parts of the summer, so that might be extending my shelf life.
 
Redhook Brewery showed me that they even clean their lines with low-dissolved oxygen water for their rinse (without any beer contact at all!) because oxygen is the scourge of beer.

At Old Dominion rinse water and any oxygen it contained was rinsed out with beer which was packaged and the first n cases sold to the employees at discount. From what I could tell it was never around long enough to get oxidized.
 
Not fast at all, actually. The number one flaw I pick up in beers I judge in competition is oxidation.

It is far too common, I'm afraid. Just racking the beer and packaging it combine to allow oxygen contact.

Can you describe the way to identify oxidation related flaws? Is it a taste changer, mouthfeel deminisher, hop presence destroyer, or something else?
 
Darkening, diminishment of hops bitterness and flavor, development of caramel - iike flavors (production of diacetyl), paper or cardboard flavors plus all the other stuff that doesn't come to mind.
 
Darkening, diminishment of hops bitterness and flavor, development of caramel - iike flavors (production of diacetyl), paper or cardboard flavors plus all the other stuff that doesn't come to mind.

Yep, those are some of them. Another one that occurs (and is actually kind of nice in a barleywine) is a "sherry" type flavor, a madeira wine flavor.

An oxidized amber ale may taste a lot like brandy, due to the development of the caramel flavors AJ noted, since it darkens and tastes a bit sweeter and the hops bitterness fades. So I would note that along with the madeira/sherry flavor notes as they are similar.
 
My home has well water that runs through an oxidizer and then a softener, and lastly (as needed) through an RO unit. I assume it is about as oxygen rich as it can get. Should I do something to mitigate this? What can be done?
 
Several things but then you don't need to do anything and in fact your water isn't any higher in oxygen than anyone else's - about 8 mg/L at room temp. Heating the water in the HLT will get rid of most of the oxygen. Some brewers go to great lengths to deoxygenate mash water and to protect it and grist component from airborne O2, to make sure that no O2 contacts the mash or wort and so on. There is a big thread going here on LDO which gets into all this. If you read that and decide that you want to be an LDO accolyte then follow some of the procedures they talk about. For most it is sufficient to take reasonable steps to protect everything on the hot side from O2 (and oxidizing agents), to oxygenate thoroughly at pitching and then to be fanatical about keeping oxygen out of the finished/packaged beer. That is where you need to focus. O2 in the package is a recipe for quick staling. Being fanatical about O2 on the hot side may, in the opinion of some, get you a slightly better tasting beer. That you will have to decide for yourself.
 
Several things but then you don't need to do anything and in fact your water isn't any higher in oxygen than anyone else's - about 8 mg/L at room temp. Heating the water in the HLT will get rid of most of the oxygen. Some brewers go to great lengths to deoxygenate mash water and to protect it and grist component from airborne O2, to make sure that no O2 contacts the mash or wort and so on. There is a big thread going here on LDO which gets into all this. If you read that and decide that you want to be an LDO accolyte then follow some of the procedures they talk about. For most it is sufficient to take reasonable steps to protect everything on the hot side from O2 (and oxidizing agents), to oxygenate thoroughly at pitching and then to be fanatical about keeping oxygen out of the finished/packaged beer. That is where you need to focus. O2 in the package is a recipe for quick staling. Being fanatical about O2 on the hot side may, in the opinion of some, get you a slightly better tasting beer. That you will have to decide for yourself.

AJ, I've measured my water after heating with a DO meter and heating alone doesn't remove the majority of the oxygen, at least not quickly. The water coming out of my tap measures 11-12 ppm and if I heat it to 150 F it will read between 5-8 ppm. It's possible in general to have dissolved gas in a liquid in excess of the saturation level for a given temperature and this can be accomplished several ways (e.g. Bubbling the gas through the liquid, allowing the liquid/gas to equilibriate at a low temperature and then heating it, etc). The same principle is why people can use pure O2 and a diffusion stone to reach DO levels in excess of 8 ppm at room temperature. Of course if you let the wort sit out long enough the partial pressure of oxygen in the atmosphere will eventually suck that oxygen out and bring the DO level down to 8 ppm.

As wise as it is to minimize oxygen exposure post-fermentation, there's another factor involved which I think most people overlook but I'm gradually becoming of the opinion that it is just as important. We actually have to consider the specific pathways that are involved in oxidation at the various parts of the brewing process, and post fermentation the main pathway for oxygen to inflict damage on the beer is via Fenton-like processes catalyzed by trace transition metals.

Something I've noticed is that some homebrewers' beer seems to show signs of oxidation damage far more quickly than others, even when their packaging procedures are similar. I believe that the underlying culprit here is the different levels of iron, copper, manganese, etc that people have present in their brewing water, as well as differences in the passivity of their brewing equipment. A lot of photos of brew kettles and such that I see show signs of poor passivation, including the rainbow colored oxides and sometimes even small rust spots. Those are going to be major sources of iron leeching into the wort and that iron is going to stick around into the finished beer and catalyze the formation of superoxides from any available source of free oxygen.

ALL brewing equipment should be stainless steel and the oxide layer should be like-new every time you brew. Water high in iron or copper should be treated with RO, and as a final precaution it's not a bad idea to use a chelating agent like gallotannin to treat the water before use. The commercial breweries that really know what they're doing are just as obsessive about ridding their source water of metals and making sure their equipment is immaculate as they are about minimizing oxygen exposure.
 
AJ, I've measured my water after heating with a DO meter and heating alone doesn't remove the majority of the oxygen, at least not quickly.
No. To completely deoxygenate it you have to get it hot enough that the Henry coefficient (solubility) goes way down and then do something to try to get it into equilibrium with a very low oxygen environment as, for example, agitating it under or sparging it with a gas that contains no oxygen. This is the method typically used by breweries (i.e. countercurrent sparging with nitrogen or CO2 in a resin bead column) but you can get more exotic than that by pumping in hydrogen with the proper catalyst present which reduces the oxygen to water.



As wise as it is to minimize oxygen exposure post-fermentation, there's another factor involved which I think most people overlook but I'm gradually becoming of the opinion that it is just as important. We actually have to consider the specific pathways that are involved in oxidation at the various parts of the brewing process, and post fermentation the main pathway for oxygen to inflict damage on the beer is via Fenton-like processes catalyzed by trace transition metals.
You are probably correct that most home brewers would not be aware of this but almost any article you read on the subject in the professional literature mentions it (at least that's my impression as I'm typing this).
 
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