Stupid question about conical fermenters and collection bottles

[MickDundee]

As I probably haven’t shut up about for the last 6 weeks or so, I got a Fermentasaurus before Christmas (standard starter kit, no pressure kit because I don’t have cronies). I’m assuming the same logic applies to the FastFerment which is why I asked about conical in general rather than just the Fermentasaurus.

When I did my first brew, I emptied the collection bottle after a week in primary, then reattached for another week at 20C and cold crashing before emptying again at bottling.

However, one thing I hadn’t thought about at the time was how attaching an empty bottle to the bottom of a full FV is going to introduce oxygen into my brew. This probably isn’t an issue with the first brew because it’s a hoppy one and I’ll probably drink it fairly quickly, but the 2nd brew is having 20 or so bottles held aside until May to present to the attendees of a friend’s stag do so if it ends up oxygenated I’m probably going to ruin people’s perceptions of home brew.

My 2nd brew has been fermenting for a week so I’m at the point where I emptied the collection bottle the first time. What am I best to do?

I think I have 4 options:

1. I could potentially purge the collection bottle with CO2 using the top of my party star tap but I’m not sure how well that would work;
2. I could empty the bottle, refill it to the top with beer from the fermenter as if I’m bottling (with a little sugar), then reattach to the FV a day or 2 later when the headspace has filled with CO2;
3. Not bother emptying the bottle until bottling day, and hoping the trub/yeast doesn’t exceed the 500ml bottle size (this won’t really help me in future when I use it to harvest yeast)
4. I could continue as I did before and hope for the best.

 

[simon12]

4 a small amount of oxygen will be dealt with buy the remaining yeast still in the beer. I think beer brewers are over paranoid about oxygen its really only an issue with wine or other things that have been stabilised.

 

[Bigcol49]

Hi!
Typical in home brewing: one problem solved, another created!

 

[dan125]

I like to get as much yeast out as possible before dry hopping which can mean emptying 3 bottles at the end of fermentation. I don't like the idea of all that O2 bubbling through the beer at that stage so I always purge them, using a spare CO2 line with a valve about 20cm from the end of the tube so I can purge the bottles from the bottom, get the lid on quick and turn off the CO2 quick.
The spare CO2 line is also very handy for pressure transfers and bottling direct from the FS with a beergun.

 

[MickDundee]

Right, so I’ve used what those in the gym game call “bro science” when I changed the bottle tonight.

I added 2 tsp of sugar to the empty bottle to encourage the yeast to eat the oxygen. I then used my partystar deluxe tap without the keg tube to “purge” the bottle with CO2 before quickly reattaching. I then bumped the temperature up to 20C for the rest of the week.

Fingers crossed!