Cold crash suck-back volume estimate?

[Vale71]

The keyword here is dissolved oxygen, as in it's already there and will instantly mix with the beer. Atmospheric oxygen takes time to dissolve and in any case the discussion here is about ways to effectively prevent oxygen ingress in the first place, particularly vis-a-vis the barbaric practice of cold-crashing. Saying "but air contains oxygen anyway so why bother?" really makes little sense in this context...
So you're saying you actually dump boiling water in your fermented beer? Must make for a very nice foam display.

 

[d40dave]

I wouldn't say it's boiling but still pretty hot. Probably about as hot as when I dump 2 cups of water with priming sugar in my bottling bucket. What foam display are you referring to?

 

[Vale71]

If you pour boiling water in even partially carbonated beer CO2 will be released and with no headspace to speak of that foam is bound to overflow. I'm guessing your water is much colder than that and therefore has a significant amount of dissolved O2, not counting what your beer has already picked up during transfer, making your process quite ineffective as far as preventing oxygen ingress is concerned compared to the alternative discussed here, i.e. no transfer with suck-back prevention.

 

[d40dave]

I thought you said it takes time for atmospheric oxygen to dissolve. I realize some people do not like secondaries for various reasons. But if one is used the problem of suck-back becomes less of an issue if the secondary has little headspace.

 

[The_Bishop]

You will still have suck-back, as the negative pressure is caused by the colder liquid absorbing more gasses, not just CO2. You also have the volume of the liquid itself shrinking due to the temperature change.

 

[d40dave]

You will still have suck-back, as the negative pressure is caused by the colder liquid absorbing more gasses, not just CO2. You also have the volume of the liquid itself shrinking due to the temperature change.

I would think that since I have less than 10 square inches exposed to gas versus 250 square inches that the rate of absorption will would be proportional but certainly less. But that is just speculation. Anyway, it's finally getting warmer around here so I'm done with cold crashing until next Winter.

I agree that all the little things add up. It's a learning process. Time, expense and other factors make for determining what's best in ones situation.

 

[OzzyPeeps]

normal breathing air in a normal environment consists of an avg of 20% oxygen. apparently I dont know what beer ruined by exposure to oxygen tastes like so why dont you enlighten me on signs of that instead of going straight to being a smart @$$ just because I dont belong to your LODO thought process.
Ive been homebrewing for over 4 years and at least a dozen AG brews.
For decades ,brewers have fermented in open vats and I dont think any of those were "ruined" by being exposed to oxygen. In fact, those open fermented beers are probably the best tasting old world styles.

Both sides of the argument are valid and correct relative to a single simple variable: how fast the product is consumed.

I plow through 5 liters a day, so even dry hopped beers are gone down the hatch before O2 is any kind of significant issue ..

I've done closed transfers into purged kegs and the loss of "high end" hop aromatics seems to be the same over the few days timeframe it takes me to drink a batch if I do that or just drink it out the FV with suck back or keg it exposed to O2

But CLEARLY, if you are storing it for any real period of time minimising O2 hermetically is the way to go because give it long enough and it WILL turn to cardboard.

Has anyone tried the new yellow kegland corny gasgets?

 

[OzzyPeeps]

These are all very basic brewing rules in the first place.

1- i dont splash when transferring except from BK to fermenter , thats it.
2- i always use O2 absorbing caps and i have never had a faulty cap seal(I use a red baron wing capper since day 1)
3- i dont purge (see #2)
4- I do not keg. I bottle...i store any unrefrigerated beer in the back corner of my basement ,in boxes ,covered. stays about 65*F .
5- my beer doesnt last long enough to worry about freshness. The few that have lasted over a year were just as good (if not better) as the first one opened 2 weeks after bottling.

Don't want to get get "sucked in" (BOOM ) To this age old side discussion and derail the thread ... but

As we all know, a keg is just a large beer bottle

The headspace is relative to the new brew which is still off gassing in the same way


I f I dry hop and it's not a closed transfer I typically purge the headspace, but again as the buddy states, it only really matters if it's not going to be chugged double time

 

[OzzyPeeps]

Think outside the balloon.

I bought a couple of undrilled stoppers and carbonation caps, like these:
https://www.morebeer.com/products/carbonation-line-cleaning-ball-lock-cap-stainless.html

I drilled the undrilled stoppers with small holes... so that the carbonation cap barb would be a tight fit, and hold a seal.

After fermenting with the normal stopper/airlock... I sanitized and replaced the stopper with the new stopper and carbonation cap before cold crashing. When the fermenter shrinks due to cold crashing, I pop a ball lock gas connector connected to CO2, and "inflate" the fermenter back to normal size with with my CO2 tank. Presto, no air introduced, and pretty darn simple.

After a time or two... I improved the process a bit by switching out the stoppers earlier. I let fermentation happen with a normal stopper/airlock for a few days... then once I am confident the most vigorous fermentation is over (and krausen isn't getting up into the airlock), I replace the normal stopper/airlock with a stopper with carbonation cap... with a ball lock connector attached to an open ended tube ending dropped into a vessel of sanitizer. Essentially, a 'normal' blowoff-tube setup... but using the stopper/carbonation cap and gas connector. When fermentation is completely over, I just remove the gas connector blowoff tube... (leaving the stopper/carbonation cap on the fermenter) cold crash, let it shrink, and attach a CO2 tank and refill the depleted headspace (and unshrink the fermenter). This method makes it so that the one time I remove the stopper early-mid fermentation... there is still active fermentation occurring, reducing the thought that oxygen will sit in the headspace.

This works great for plastic fermenters, which simply "shrink" due to cold crashing. The stopper has always held a seal, as is apparent by the 'shrunk' fermenter. I've also done similar things with SS fermenters.

If you're cautious... you can just add a burst of CO2 a couple of times as the temperature is dropping, rather than all at once at the end of cold crashing.

And if you don't keg... and don't have a CO2 tank on hand... the above post was unhelpful. (And you should consider kegging!)

Love it.


Will it work for my 160l brew in a water butt though, so I can free up kegs and effectively treat that primary as a large keg till the steel is ready ... my real purpose and how I alighted on this thread.

Not perfect but did for thought

 

[OzzyPeeps]

So again, why not cold crash in the keg where you can pressurize it and basically no chance of suck back if your stuff is working correctly? Why does the cold crash have to be in the primary?

It doesn't, and this is what I do - as I have a kegerator that fits kegs and not a fridge or freezer big enough for my primary fvs.

It's fine. It works like a charm.

But it's not perfection. It's not optimal.

Optimal is drop what you can as fast as you can, as soon as you can in primary - then drop the rest in the keg

The difference it makes is going to depend on the brew.

Heavily dry hopped gear in primary will benefit more from a crash in primary ( and maybe a touch of gelatin) in primary before the final clean up in the can - but it also depends how much you really give a **** about crystal clear beer.

 

[jerrylotto]

You will still have suck-back, as the negative pressure is caused by the colder liquid absorbing more gasses, not just CO2. You also have the volume of the liquid itself shrinking due to the temperature change.

Water volume change by temperature is pretty negligible, the bigger change is the volume of gas overhead shrinking (decreasing pressure). You can use the ideal gas law PV=nRT as an approximation - pressure in the headspace is approximately proportional to temp (in degrees Kelvin)- dissolving C02 reduces "n". Water shrinks slightly with decreasing temp above 4 degrees C and then expands again as temp drops below 4C until it after it freezes with decreasing temperature. Best way to cold crash IMHO is under positive CO2 pressure in a keg.