In my ongoing quest to make my brewing process as perfect as possible, I’ve hit an impasse - I can’t figure out if it even is a problem. And then, I don’t know how to fix it anyway. Here’s the essence of it:
Cold crashing wort after fermentation causes the beer to condense; the consequence of which is the intake of air (or starsan).
Obviously installing a filter will prevent any spoilers from getting in, but I also think about staling brought on by post-fermentation exposure to oxygen.
So is the amount of oxygen so small as to be insignificant? If true then yes indeed, I am being too anal.
Do pro-breweries address this? If so, what do they do?
No, I have not experienced any of the negative effects this post is concerned with, I’m just trying to fine-tune my process.
I think you are probably being a little too anal. The addition of a little starsan is no problem, and the amount of oxygen that may be pulled in is negligible when compared to the amount introduced when racking to a bottling bucket or keg (assuming they are not purged).
It is honestly something that I have never considered in the past and would not worry too much about it, but that is me.
I cold crash in the keg while I force carb - when the outside air gets a chance to find equilibrium, that means the keg just kicked and I’m cleaning it. But when I crashed in the fermenter I always felt that the air must’ve been sitting on top of the heavier blanket of CO2, because my beer wasn’t oxidized from it. I’m just more confident crashing in the keg now.
I agree with all of this. In addition, by the time you;re ready to crash it, there’s no need to use an airlock. Use a stopper like Dan suggested, or do what I do…rubber band some foil or plastic wrap over the top.
It is absolutely best to limit o2 exposure wherever possible. But as I learned from a conversion with another forum member recently, on unfiltered beer oxidation damage is much less of a concern. I don’t think the vacuum you are creating is a problem. I do think that lagering in stainless with positive co2 pressure is your best option, however.
There is only so much you can do about it if you are using a carboy. Even if you use a solid stopper then as soon as you take the stopper off it will suck in the ambient air. I guess you could put on a solid stopper, then crash cool and then let it warm back up before you transfer it. Also, you can use a solid stopper, then crash cool and then open the carboy and shoot in a few blasts of co2 before you close it back up. Not sure it is something to worry about, but if you are trying to save beer for a long time, the less oxygen the better.
Professional breweries have pressurizable conical tanks. Usually you will cap off the tank with just a little bit of fermentation left to go to start building up some pressure inside the tank. This allows the pressurized co2 to just be absorbed into the beer once it cools down, and even when you open the tank after chilling there is positive pressure.
I heard somewhere recently of a guy using a cask breather on his fermenter during cold crash to avoid oxygen influx. Seems a bit of overkill, but then again, that’s what we do.
Typo and incorrect word fixed. Yike. I always read a post 2-3 times before I hit ‘Post.’
I ferment in a stainless conical - I guess I also should have said that. I can just put a tri-clamp cap on the lid, but I think it’ll just suck air through the gasket. I hear you all say that it doesn’t matter, so on to the next ‘system improvement project.’ Thanks for the input.
I don’t believe it would suck air through the gasket. Though depending on on thin your conical is I suppose there is a small chance it could implode a bit :D. I have not done it with my conical (i just let it suck in air and then purge with co2 a day or so later). With my glass carboys I typically let them have a bit of a vacuum using the breathable silicone bungs (lets things out but not in). Even if you let in the rush of air when you take the bung out it’s still better than the air sitting in there the whole time it’s cold crashed…
Can your conical take a little bit of pressure? You could connect you co2 tank at low pressure while chilling and you will have nothing to worry about.
So I too have been wondering about this for a while and have read quite a few threads on the topic. The obvious real answer to avoid this is simply to close-transfer from primary directly into the keg, purge with CO2 and then cold crash in the keg. I just see problems with this when using lots of dry hop pellets or even fruit additions in the last fermenter before transferring clogging up the dip tube which is a whole other problem.
I read that some say simply to place plastic wrap over the mouth of the carboy. Plastic wrap is gas permeable as far as I know. Now, how fast and how much gas can permeate through the plastic wrap I am unsure of, especially over the course of a 48 hr. cold crash or so.
Some say to use foil over the carboy mouth. Foil will allow oxygen to ingress into the carboy when the temps inside the fermenter headspace drop simply because it is not airtight even with a rubberband.
I myself have always used an s-shaped airlock filled with a small amount of starsan. I have not lost any starsan into the fermenter but have noticed “air” being sucked back into the fermenter as the pressures and temps change. I have not really noticed any major oxidation with my beers using this fashion and wonder how much O2 if any really gets into the beer itself since it is so cold and not typically agitated for the solutions to mix.
I like the idea of the stopper except that it too will bring in oxygen when the stopper is pulled out prior to a gravity reading or transferring. The only upside is that it may minimize the time oxygen contacts the beer as you are only spending a handful of minutes getting a gravity reading/setting up your transferring equipment vs. a 48 hrs or so of oxygen ingress.
I do not agree that the CO2 creates a blanket that protects the beer though, simply b/c as the beer cools the CO2 in the headspace is absorbed into the beer which in turn pulls the oxygen in. I think the AHA needs to conduct a cool experiment on this one simply to see what minimizes oxygen exposure the most ($).
Maybe a combination of all of these techniques is best and should be addressed in an experiment. Foil + wrap? Stopper minimizing oxygen ingress time and allowing the beer to warm up to room temps so O2 doesnt rush in when its removed?
Sorry for the rants…Just had a lot to say on the topic. Any extra thoughts?
