It seems that an IPA I’ve had in bottles for perhaps 2 months or so has become darker in colour and the sediment at the bottom of the bottle that I pour out, seems to be darker and slightly greyish in colour. Does this seem normal? It doesn’t taste like it has gone off. It started out quite golden and has gone more towards an amber/red colour.
The darkening could certainly be from oxidation. As far as the sediment goes, hops do drop out over time so that’s my guess. The only time I ever saw a bottle of Maharaja in my area it was covered with flecks of gray sediment on the bottom of the bottle. As much as I wanted to snap it up, I knew that the sediment meant it was way past its prime.
+1
Interesting. I would say the flavour has probably changed but it doesn’t exactly taste like it has gone off.
Do you think it is likely that the oxidation may have occurred whilst in the bottles? (An interesting thing I noticed lately, where I buy my ingredients etc. from - Their bottle caps never said that they were oxygen barrier caps and recently they have started selling new caps that specifically say that they are ‘oxygen barrier’. I wonder could this be the culprit?)
You are likely not using oxygen barrier cap. The O2 ones cost more, so it is unlikely to be the default cap at your LHBS, and the O2 ones are usually clearly marked (so you know why they cost more) in the shops I frequent.
The darkening of beers is nomal. Oxygen (and other things) in the beer from transfering will darken the beers over time. Some brewers go through great lengths to keep O2 away from beers, doing “closed transfers” so the beer is not exposed to the atmosphere. Hot Side aeration…and many other topics all add opportunities to add oxygen effects to the beer.
This great care in reducing oxygen exposure slows the rate, but does not stop it. The more O2 exposure during your process and bottleing, the faster it will occur. (Note O2 is not the only thing that causes the beer to darken, just one of the main reasons)
I have noticed that beers stored warm, darken much faster than beers stored cold. So that is another tool that can slow it down.
Lastly, I have found that as things drop out of my beers with aging, and it goes from slightly hazy to opulescent to clear, the beer seems to appear to darken. The light simply passes through and you can see all the way through the beer, instead of only part way.
In the end, if it still tasts good, I would not change a thing! If the beer is beginning to get sweeter over time or pick up cardboard flavors, then make sure you are capping good, watch the splashing on transfers, and keep it cold are the easy things. The O2 caps might help as well, but better to keep the O2 out in the first place rather than add stuff to take it back out.
Enjoy!! I am jealous! I have been out of IPA for a couple months and I could really go for one right now!
My guess would be, as others have said, oxidation as the cause of the darkening. Wingnut makes some very good points about taking care to avoid oxygen pickup throughout your process.
On the subject of bottle caps, the choices are oxygen absorbing, oxygen barrier, and regular crown caps. I think oxygen barrier is just a fancy name to get you to pay more for your caps. Any cap with a gasket(all of them!) is an oxygen barrier cap. I’m not convinced oxygen absorbing caps are worth the extra cash. Does anyone know what material these caps contain to absorb oxygen? Or how much oxygen they absorb? I only bottle a few beers here and there from kegs and I admittedly use oxygen absorbing caps for the peace of mind. But I am not convinced they do anything to protect my beer from oxygen. If you really want to stop oxygen in your packaging, I would recommend kegging because ALL crown caps let in oxygen over time.
It’s probable that most of my oxidation issues occur during my bottling stage. It’s something that I’ve always felt uneasy about (the beer being exposed for so long during the process) so I need to think of ways to reduce contact with oxygen for such a relatively long time. I’m not in a position right now to have a kegging set up, but is something I would definitely like to do in the future.
I agree with the O2 absorption comments regarding beer caps. Doesn’t O2 get absorbed into the bottle caps while sitting in the bin?
I also agree with the others regarding the O2 absorption changing the color along with sediment dropping out offering changes in color due to light refraction. This has been a topic discussed on other forums.
In regards to O2 absorption during the bottling stage, I’d like to offer my opinion. Although no one has stated exactly how much O2 is absorbed during bottling, other than “not much” to “not sure,” I have always used a layer of gas over the beer during bottling using a can of “wine preserver” you can get from any major wine store. It is a can of gasses you place in a wine bottle to preserve it by avoiding more oxygenation, but works great with beer too. I moved on to kegging and now ALWAYS place a layer of CO2 gas in every container prior to placing beer in it. I went from bland tasting beers, due to oxygenation resulting in a cardboard-ish taste, to crisp clean beers.
I hope this was helpful. I have an O2 meter, which I plan on experimenting to determine how much O2 is absorbed during bottling. I’ll post it when done.
Cheers,
O2 caps are activated when wetted. I guess it’s magic.
They have a limited working time from what I have read, and don’t stop further o2 from seeping in any better than other quality caps.
How is it possible for oxygen to seep into a bottle after it is capped and carbonated?
Just curious
The seals aren’t 100% perfect. The amount would be small I’m sure.
yup, over 50 or 100 years you’ll lose all your carbonation too.
I always set caps on the bottles as I fill them. Basically, fill a bottle, move wand to next bottle, set cap on the top of just filled bottle.
My reasons are likely completely bogus but it has always worked for me. I assumed that by setting the cap on the bottle loosely, any CO2 that comes out of solution will push oxygen out of the bottle and the cap will make it less likely that more air (or bugs) will find its way back into the bottle. Low tech, easy and maybe effective who knows.
Paul
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I always set caps on the bottles as I fill them. Basically, fill a bottle, move wand to next bottle, set cap on the top of just filled bottle.
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Yes, I normally do this too.
I wonder would it be better to rack to a ported Better Bottle, rather than a bottling bucket, and bottle from there? The smaller neck would surely allow less contact with oxygen during the process? I’m also beginning to think that the tubing that I use with my auto siphon when racking to bottling bucket is a touch too loose and the beer is being aerated to some degree at this point?
According to our resident yeast expert, S Cerv…, much of the oxygen will be consumed by the yeast as the carb.
I’d bet a six pack that more oxygen is introduced from the head space after capping and jostling the bottles around. Unless of course co2 is used to purge the headspace of each bottle.
Edit - phone changed of to if. So ducking irritating. [emoji12]
According to Charlie P, The Home Brewer’s Companion, referring to plastic pet bottle:“although there is pressure in a bottle of beer and it seems that because of that outward pressure, no air would ingress into the beer, it doesn’t happen that way. Why? Because the outward pressure is created by only carbon dioxide gas. There is no oxygen gas inside the beer pushing outward ; consequently, it’s as though the oxygen sees a void and thus makes it’s way in, slowly. There is a very small amount of air ingress through the seal of a bottle cap as well.” He cites Boyle’s law “which has to do with the observation that gases will seek equilibrium in the environment they are capable of inhabiting.”
It seems as though “air tight” doesn’t necessarily mean “oxygen impermeable”. And PET plastic and crown cap gaskets are oxygen permeable but what about the rubber gasket on Grolsch-type botlles or kegs? Is it oxygen impermeable? I don’t know. What about the oxygen permeability of modern beer bottles which are a glass-plastic blend vs. Old-school recyclable bottles which are 100% glass. So what is truly THE best way to protect beer from oxygen? My guess is a keg with the headspace purged occasionally.
BTW, Charlie P is still the man just as much as anyone whom is more recently “beer-famous”.
I have noticed the quality of my beer seems to go down a noticible amount (color and carb) when I bottle from a keg. After a few months of reworking my bottling process I think it may be due to temperature swings in my cheap garage fridge (24 to 48 degrees F), but I am still testing and measuring. Has anyone else seen where temperature changes in the glass bittle affect the seal of the bottle over time? Or am I chasing a unicorn?
I wonder if the reason why it is darker is simply because the yeast has dropped out of suspension. When a beer is cloudy it usually doesn’t look as dark as when it is clear. All you have to do is check out a fermentation in a carboy. Even a red beer will look “milkish” during fermentation and will actually appear to darken as the yeast drops out.
As far as the rest of the conversation: I do think oxidation can cause beer to darken. And I do think that active yeast during natural carbonation will help minimize the effects of o2 pick up. But this is only if oxygen pick up is minimal.
As far as the oxygen absorbing caps go, they work pretty well. But some have shown that they also absorb hop aroma. So consider that when using them.
I know, it’s hard to believe that it happens but it does. It has to do with atmospheric pressure and the exchange of gasses. Cans will oxidize too due to the seal at the top of the can, though some think less fast as bottles (though I have my doubts after seeing a few canning lines in action and seeing a few cans seeping at the seams.)