Beers changing flavor after a few weeks

“If you leave head space in your bottle you're leaving O2 in the beer.”

There is most definitely some oxygen in the headspace of a beer that has just been bottled. During the bottle conditioning phase a true secondary fermentation takes place:

· The yeast consumes the priming sugar (fermentation)

· The yeast utilizes oxygen within the bottle during the secondary fermentation

· The yeast produces CO2 as part of the fermentation which carbonates the beer

The bigger issue with bottling is that the cap liners are not oxygen impermeable and therefore over time oxygen will indeed ingress into the bottle over time. This ingress is a slow process and as I have reported above I obtain long shelf-lives for moderate gravity non-hoppy bottled beers: about 9 months.

There are caps that have oxygen scavenging ability and therefore will mitigate the ingress of oxygen through the cap liners. I have zero experience with these types of caps.

Kegging has the advantage that a sealed keg is oxygen impermeable.

Cheers!

 

I'm wondering if the mesh bag over the end of your auto siphon could be the culprit, I've tried this before myself and had a bottled ipa turn out the same way as yours did. Could the beer flowing through that fine mesh cause enough turbulence to pick up some O2?

 

“Could the beer flowing through that fine mesh cause enough turbulence to pick up some O2?” There should be no oxygen dissolved within the beer.

Cheers!

 

+1 - I think you shoud avoid using it.

BTW do you store your beers in a cool dark place?

 

Esteban (@Tebuken ) brings up a very good point. The oxidation processes in beer follows the Arrhenius Equation. If you have a dedicated beer refrigerator where you can store your bottled hoppy beers that will ****** oxidation (e.g., hop fade). Cold storage ******s the oxidation processes.

Cheers!

 

Yep. Or put another way... No new oxygen will get into your beer as a result of putting a mesh bag over the end of the auto siphon, assuming the bag is on the input end. (Apart from a negligible amount forced in by agitation at the surface of the beer as the porous bag is being pushed through the beer surface on its way to the bottom.)

Putting it on the output end would be a great way to dissolve lots of O2. It sounds silly, but IIRC it has been done.

 

OP: I had one more thought.

Apart from the EZ-Cap bottles you're using, how are you sanitizing your caps?

 

Cool. Just checking.

 

Until that bag is fully submerged, you're continuously running beer through it at the Beer to Air Interface (BAI, it's a technical term). I wouldn't do that.

ETA: and even after its submerged, you're still probably making some fine bubbles that are getting to the surface, increasing surface area, and thus O2 dissolution.

 

Ah, I thought you had submerged the mesh bag on the end of the autosiphon in the fermenting bucket.

In your case, the mesh bag acts like a faucet aerator. Rather than the beer flowing as a continuous stream, the mesh bag basically slices into tiny, mesh-sized streams, increasing surface area and allowing increased contact with the air.

Take the aerator of your kitchen sink faucet if you can. You'll notice a distinctly different stream that comes out as opposed to when the aerator is attached.This is essentially the difference between the mesh bag in the bottling bucket versus not.

 

Or find a way to keep large amounts hop debris out of your fermenter, such as bagging your dry hops.

 

OP, this is what I do. 5 gallon paint strainer bags, boiled for a few minutes with a couple stainless steel bolts for weight and tied with sanitized fishing line. I've done up to 6 oz of dry hops for 5 gallons in a single bag. On bottling day I use a pair of sanitized tongs to wring the bag into the bottling buck at the very bottom when it's empty. The farther the beer falls and splashes, the more oxygen you're letting in. Then I gently pour in my priming solution, and rack the rest on top.

 

I personally bag my dry hops in a sanitized muslin bag which includes marbles to weigh down the bag. No clogged siphon for me!

Cheers!

 

What size bag are you using? 6 oz of pellet hops in a 5-gal. bag spreads out plenty.

I saw a picture somewhere on these forums of Sierra Nevada prepping dry-hop bags of whole leaf Cascade for Bigfoot. The bags were stuffed tight. If it's good enough for Bigfoot, it's good enough for me.

 

Seems to me that the problem in some cases at least...is a failure to drink enough beer to approach equilibrium