[Ellismr]

I have a SS Brewtech BMC conical fermenter.  I recently brewed a NEIPA the dry hop was 1.75 lb in 11 gal batch.  I cold  crashed for three days and closed pressure transferred to kegs.  When I started the crash I removed the blow off tube and installed a spike pressure manifold to cap it off.  As it cooled I'm wondering if O2 was sucked in around the BMC lid.  I wold think not with the silicone gasket and the slight vacuum caused by the cooling. 

The end product doesn't have the nose that previous version did but other factors that may have an impact are yeast and hop selection.  I usually use A38 The Juice from Imperial but I couldn't get it and used Lallemand New England strain.  I also couldn't get enough Citra and subsistuted Idaho #7. 

Any thoughts you might have are appreciated.  Cheers!

[Die Beerery]

I’m not sure what your specific problem is, however. It doesn’t matter what you crash cool in, the pressure differential and the laws of partial pressures means that oxygen is getting in.   Silicone, and pvc (probably your transfer hose) permeability is very high meaning that gas exchange is going to happen in a short period of time. The larger the gasket or surface area the worse off it it. Also co2 has oxygen as well.
However hop fade IS oxidation, so if you noticed it post crash and racking it’s coming from some/all of your cold side process. 


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[BrewBama]

Maybe you could hook up CO2 while you’re cold crashing. As the pressure drops instead of sucking in O2 it’ll be sucking in CO2. It’ll still have O2 in it but at least it’s not 100% air.


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[Die Beerery]

Maybe you could hook up CO2 while you’re cold crashing. As the pressure drops instead of sucking in O2 it’ll be sucking in CO2. It’ll still have O2 in it but at least it’s not 100% air.


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While that may help, it certainly won’t stop the gas exchange with the air outside of the fermenter. 


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[goose]

Maybe you could hook up CO2 while you’re cold crashing. As the pressure drops instead of sucking in O2 it’ll be sucking in CO2. It’ll still have O2 in it but at least it’s not 100% air.


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This is what I do.  I have both a half barrel and a 7 gallon SS Brewtech fermenters.  Once the fermentation is complete, I quickly remove the blowoff and cap the top of the fermenter with a cap that has a gas-in keg plug on it and hit it with about 3 PSI of CO2.  That way I can burp out the yeast and hops (when I dry hop) in the fermenter without introducing any oxygen into the ferrmenter.  I do not cold crash until I do a closed transfer to the keg pusing the beer with CO2.  I then cold crash the keg in my lagering freezer and carbonate at the same time since I am not set up to cold crash in the fermenter.  Incidentally, the gasket on the lids of these fermenters, seal really well (at least mine do) since the they both hold pressure.

Another idea when dry hopping (if you can do it) is to run CO2 into the ferementer when adding the dry hops, if you have a second port on the lid and if you are dry hopping after hitting terminal gravity.  We did this when I was doing my pro gig and it seemed to work pretty well.  Just a thought.

I do not dispute Die Beerery's analysis that O2 can be getting in through the gas permeability of the transfer tubing because yes it is a very good possibility.  That said, I have used vinyl tubing for my transfers for years and have nor really have a problem with hop fade in my dry hopped beers other than normal degradation from age.  I do make sure that the transfer tubing is flooded with beer or totally purged with CO2 before I start the closed transfer to further prevent O2 ingress  I have a black IPA that had been lagering since late January and put it on tap a week or so ago.  It still tastes fine and I have noticed no oxidation issues.  Granted, beers like IPA's and Hefe's have a shorter shelf life and will start to taste old sooner than something like a porter, stout, or wee heavy.  I usually start to notice this when I get to the bottom of the keg on those lighter beers, but by then the keg is almost ready to kick.

[Die Beerery]

Maybe you could hook up CO2 while you’re cold crashing. As the pressure drops instead of sucking in O2 it’ll be sucking in CO2. It’ll still have O2 in it but at least it’s not 100% air.


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This is what I do.  I have both a half barrel and a 7 gallon SS Brewtech fermenters.  Once the fermentation is complete, I quickly remove the blowoff and cap the top of the fermenter with a cap that has a gas-in keg plug on it and hit it with about 3 PSI of CO2.  That way I can burp out the yeast and hops (when I dry hop) in the fermenter without introducing any oxygen into the ferrmenter.  I do not cold crash until I do a closed transfer to the keg pusing the beer with CO2.  I then cold crash the keg in my lagering freezer and carbonate at the same time since I am not set up to cold crash in the fermenter.  Incidentally, the gasket on the lids of these fermenters, seal really well (at least mine do) since the they both hold pressure.

Another idea when dry hopping (if you can do it) is to run CO2 into the ferementer when adding the dry hops, if you have a second port on the lid and if you are dry hopping after hitting terminal gravity.  We did this when I was doing my pro gig and it seemed to work pretty well.  Just a thought.

I do not dispute Die Beerery's analysis that O2 can be getting in through the gas permeability of the transfer tubing because yes it is a very good possibility.  That said, I have used vinyl tubing for my transfers for years and have nor really have a problem with hop fade in my dry hopped beers other than normal degradation from age.  I do make sure that the transfer tubing is flooded with beer or totally purged with CO2 before I start the closed transfer to further prevent O2 ingress  I have a black IPA that had been lagering since late January and put it on tap a week or so ago.  It still tastes fine and I have noticed no oxidation issues.  Granted, beers like IPA's and Hefe's have a shorter shelf life and will start to taste old sooner than something like a porter, stout, or wee heavy.  I usually start to notice this when I get to the bottom of the keg on those lighter beers, but by then the keg is almost ready to kick.

I don't want to fear monger here, but this is not normal. What is oxidation to you? Because oxidation is everything I highlighted. If you want me to explain why I can, otherwise I will bite my tongue and move on.

[BrewBama]

Anyway, It sounds like you closed transferred so that’s good. ...but the cold crash in the FV probably did you in.

You might try transferring with a few points remaining in the ferment, attach a spunding valve and let the yeast consume any O2 you may have picked up in the transfer. Then, after it’s finished fermenting in the keg, cold crash with CO2 pressure applied. Yeast are awesome at eliminating O2.

As a side note, I recently listened to an interview with Charlie Bamforth. He basically said to preserve flavor quality and stability — especially with the IPA(s) — the two main things are temperature and limiting oxygen exposure post fermentation.  He reiterated several times that you can do all the low oxygen techniques early in the process you want but if you fail in keeping the beer cold and limiting O2 post fermentation you’ve wasted your time.

He recommended starting at the end — concentrating on packaging and keeping the packaged beer cold for the most gain — then working your way towards the beginning, progressively gaining smaller and smaller impacts on the final product. He even said that if a beer exhibits the tell-tale ‘cardboard taste‘ staling effect, you can run the beer thru yeast and it will clean up the off flavor.

Of course, the difference in yeast and hops you used created a different beer than previous versions so it would be tough to compare one to the other except to say you may have preferred your previous recipe.

It reminds me of a post I once read where a brewer used a ‘clone’ recipe from a fellow brewer. He said he followed the directions exactly ...except he had to substitute the base grain for what he had on hand, and he used different hops, and he couldn’t get the same yeast ...and the beer didn’t taste anything like the commercial beer he was trying to emulate.  The clone recipe was crap. 😂

Hope this helps.

[Ellismr]

Thank you all for your insights.  With these IPAs I think that hooking up CO2 at a low pressure while your cold crashing is probably the key.  The IPA that I did with my spike fermenters as a pressure rating of 15 pounds and I’m able to maintain that with a pressure transfer manifold I see that as being probably the key difference between the two batches that I did.  Thank you again I’ll keep going at it till I nail this one.


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