Sour beer making sides of my plastic bottles 'thinner'

[rruotolo]

I like using plastic to bottle my beers in. It's lighter, and I can see how the carbonation process is going just by giving the bottle a squeeze.
Problem: I have a kettle brewed sour I made. I moved it from the secondary to the bottling bucket, added some corn sugar and bottles it. It's been about a day and the bottles are now 'thinner' than yesterday. Thinner as in the sides of the bottle are buckled a little inward. I can slowly open one of the screw caps off and hear a little air going INTO the bottle. I've had this same thing happen a number of months ago with a long sour I made, when I went too long (about 14 months) and it turned to vinegar. I think I did the same this time, with a pH= 3.4, which is pretty sour, but the taste is gone.

Anyone heard of this and know what's going on? This kettle sour is a kit I've had good luck with in the past.

 

[sibelman]

Has the temperature dropped?

 

[sibelman]

I've seen plastic bottles shrink like this, over months, as something diffuses out through the plastic. Hasn't been beer, though. Hmmm...

 

[rruotolo]

The temp hasn't dropped - it's been in a temp controlled fridge. And it's been in there for only a day. The bottles are also considerably softer than when put in there a little over 24 hrs ago, so this isn't a temp/pressure thing -the brew is acting funny. This same thing happened with the long-term sour (mentioned in OP)

 

[bruce_the_loon]

The temp hasn't dropped - it's been in a temp controlled fridge. And it's been in there for only a day. The bottles are also considerably softer than when put in there a little over 24 hrs ago, so this isn't a temp/pressure thing -the brew is acting funny. This same thing happened with the long-term sour (mentioned in OP)

You say they are in a temperature controlled fridge, is the set temp for the fridge lower than your ambient room temperature. I know I get plastic bottles collapsed slightly like this when putting an unpressurized bottle at room temp into a cooler environment. Even 3 or 4 degrees can do it. Once they are pressurized by the carbonation in a few days, they should go hard again.

Consider that while the beer in the bottling bucket might have been at or close to the fridge temperature, the air remaining in the headspace was not and would shrink when cooled.

 

[Beermeister32]

There has been a temperature drop with an uncarbonated beverage in a soft sided container. Same thing happens with cold crashing a carboy with the suck-back issue. A slight temperature drop has the plastic bottles pulling inward, there is a slight vacuum created by the temperature drop.

Your beers should be allowed to carbonate at room temperature. Sometimes sours continue carbonating. If they were in glass, I’d suggest placing in a storage tote for safety. Plastic might be a good idea too until carbonated.

Once they have a good carbonation on them, you can refrigerate. Here’s a batch of sours I did using high pressure glass Champagne type bottles:

 

[IslandLizard]

That ^
As @Beermeister32 said, the beer and air inside the capped plastic bottle shrinks when getting cooler, reducing its volume. Since your bottles are made of soft plastic they start to collapse until pressure inside matches that of the atmospheric pressure outside. Nothing unusual.

And yes, they need to carbonate at higher temps (say, between 55-70F); the fridge temps are likely too cold for the yeast to be active enough, and would take a long time. Kettle sours don't age well, better to let them carbonate faster, so they can be consumed earlier, not years from now.

 

[atzemis13]

There has been a temperature drop with an uncarbonated beverage in a soft sided container. Same thing happens with cold crashing a carboy with the suck-back issue. A slight temperature drop has the plastic bottles pulling inward, there is a slight vacuum created by the temperature drop.

Your beers should be allowed to carbonate at room temperature. Sometimes sours continue carbonating. If they were in glass, I’d suggest placing in a storage tote for safety. Plastic might be a good idea too until carbonated.

Once they have a good carbonation on them, you can refrigerate. Here’s a batch of sours I did using high pressure glass Champagne type bottles:

Those are the coolest bottles I've ever seen! Can I ask where you got those?

 

[Beermeister32]

Those are commercial sours bottles and Lindeman's lambic bottles. They have been fitted with vintage European ceramic stoppers from various brewers. They use a regular Grolsch ligature, a full rubber seal (like a top hat, not the one like a washer) and have #12 electrical wire holding it all together like the US stoppers back in the 1890's. Plus solder, finishing and polish. Takes a while to figure out the geometry adjustments to make them close like champs, but when you have them adjusted, they are perfect. Prost!

 

[atzemis13]

Those are commercial sours bottles and Lindeman's lambic bottles. They have been fitted with vintage European ceramic stoppers from various brewers. They use a regular Grolsch ligature, a full rubber seal (like a top hat, not the one like a washer) and have #12 electrical wire holding it all together like the US stoppers back in the 1890's. Plus solder, finishing and polish. Takes a while to figure out the geometry adjustments to make them close like champs, but when you have them adjusted, they are perfect. Prost!

Very cool, thanks for the info!