Headspace in secondary fermentation (PET carboy)

[PokerDad]

I'm getting ready, in a few days, to rack my wort from primary (white plastic bucket snap-on lid and airlock bubbler) to secondary (clear PET carboy with rubber stopper and the same airlock bubber).

Both are sized for 5-gallon batches, but due to my inexperience on brew day (5 days ago) I only ended up with about 3.5 gallons of wort.

Back story: The recipe is for NE IPA and included a 'whirlpool hops addition' after the boil, which I didn't know how to do, so I ended up with trub not only at the bottom, but mounded up in the middle of the brew pot, and I could barely find any "clear" liquid to siphon off, so I ended up with only 1.5 gallons of usable wort from the 2.5 gallon boil. After adding water in the fermenter and checking OG, it was 3.5 gallons.

I know plastic vessels are discouraged because they allow gases to pass through their porous walls, but it's what came with the kit and I haven't (yet) decided to invest in better gear, so it's what I've got. I've read that during active fermentation, it's not a big deal because the net pressure is outward, and my airlock has been bubbling happily the past few days, but it's starting to slow and now I'm pondering the next phase (secondary).

Would it be a mistake for me to rack my NE IPA into the PET carboy when I only have 3.5 gallons? Will that amount of headspace be a problem? There will be dry-hopping added during secondary, per the recipe, in case that would factor into your advice for me.

Thanks in advance!

 

[RM-MN]

Would it be a mistake for me to rack my NE IPA into the PET carboy when I only have 3.5 gallons?

Yes, you would leave a lot of headspace.

Will that amount of headspace be a problem?

Yes. It is fairly likely that you will end up with an infection and for sure you will be oxidizing the beer, not a good thing with an IPA. You would do better to just leave the beer in the primary and dry hop it there. Have the hops ready to go in and just open the lid sufficient to get them in, then close it quickly to minimize the oxygen exposure. Your IPA will be pretty good for the first 3 months as the hop oils oxidize and lose their aroma.

 

[Knightshade]

With proper steps, I'm not so sure I'd worry about infection. Oxidation on the other hand is a much bigger problem with what you're proposing, and possibly already being introduced via your current setup. NEIPAs are particularly fussy with that sort of thing.

If you're able, and you've got your DH prepared I'd recommend hooking up some CO2 and pushing that hose (I'm making some assumption with your described setup) into the hole of the airlock bung. Then crack the lid as quickly as possible, throw in your DH and let the gas flow for a little bit longer with the presumption that you'll be filling the headspace with CO2, while reducing the amount of O2 in there as it pushes up and out via the lid which is just sitting on top. When you feel this has been accomplished, remove the gas, pop the airlock back on and seal the lid.

If somebody else wants to validate/add to above, that would be awesome.

 

[bellhp]

RDWHAHB ... I would just leave it as is ... secondary fermentations are only warranted for long lagering IMO . next brew just go straight to the carboy and just use the bucket for bottling .

 

[hotbeer]

Moving your beer to a secondary isn't a task for a beginner. More to it than just siphoning from one container to another. Lots of stuff you need to do to mitigate the very likely chance you'll oxidize your beer.

Once you've tasted a bunch of batches you left in the primary FV till bottling or kegging day, then you'll wonder why they even recommend a secondary.

I don't use a secondary, even for beers I've let stay in the FV for six weeks.

So my recommendation will be do nothing. Leave the beer where it is and wait till it clears itself up before you do anything else with it.

 

[Broken Crow]

I'm assuming you're brewing from a kit and the thing about kit-recipes is that they're like the Pirate's Code... pretty much just guideline. Personally, I'd just lift the bung & airlock and drop the hops in, immediately replace the bung & airlock and then count on waiting at least a week or 2 longer than the recipe tells you to.

 

[PokerDad]

This is all great advice and very helpful -- thanks. Here are my main takeaways:

-- secondary fermentation is not needed for the type of beer I'm making, and poses an unnecessary risk of oxidation and/or infection. Don't know why Brewer's Best ingredient kits are still recommending it. Both of the BB kits I've used (Dunkelweizen last summer, and NEIPA now) recommend it. (@hotbeer this is probably how my Dunkelweizen picked up an odd flavor last summer.)

-- since I've got some blanket of CO2 accumulated in the white bucket, it's best to keep it intact as much as possible, thus the quick-toss-then-reseal approach to dry hopping (@Broken Crow and @RM-MN). If I wanted some extra insurance, I could purchase some CO2 and a hose that fits the airlock hole, and after dry-hopping, push CO2 into headspace with the lid loosely seated, to force out any air that's hanging around in there (@Knightshade ) before resealing the lid.

And I like @bellhp's idea for the future, to just use the clear PET carboy as the primary, which will also let me see what's happening in there. The white bucket makes it impossible to know what's happening in there, other than the bubbling activity through the airlock.

 

[Broken Crow]

Just a heads-up that most homebrewers discover for themselves when brewing from "5-gallon" kits....You never actually end up with 5 finished gallons, and often, much of the losss comes from putting 5 gallons of wort and yeast into a 5-gallon fermenter..[you can lose a lot to blow-off depending on how vigorous a primary fermentation you get}. Adjust your expectations of getting a ful 5-gallons from a five gallon kit and use whichever of your bucket or carboy gives you greater headspace.

 

[PokerDad]

[...] use whichever of your bucket or carboy gives you greater headspace.

and by "greater" you mean less headspace, so less concern about stray air/oxygen, right?

 

[Broken Crow]

If you get krausen blowing out your airlock, you've pretty much pushed all the oxygen out, but too much krausen is actually some of your beer blowing out....It's a balancing act that depends on what type of brew you are doing, but for most of my own beers, I like at least a gallon or so worth of headspace... I usually do 6 to 6.5 gallon batches in 7-gallon Fermonsters, or a 12 gallon batch into a 14 gallon Fermzilla or 15.5 gallon Sankey keg.

 

[SanPancho]

And I like @bellhp's idea for the future, to just use the clear PET carboy as the primary, which will also let me see what's happening in there. The white bucket makes it impossible to know what's happening in there, other than the bubbling activity through the airlock.

using PET means you can see what's going on, and that's nice and all, but the more important reason is that PET is way less oxygen permeable than hdpe. especially good if you're letting things take their time and its gonna be in fermenter for weeks.

added bonus is that if you need to open it to take sample, add hops/salts/chems/etc, the opening is much smaller on PET carboy vs a bucket lid, which also helps limit oxygen.

 

[RM-MN]

and by "greater" you mean less headspace, so less concern about stray air/oxygen, right?

No, he means more headspace. The amount of headspace only really matters when it isn't enough and your krausen puts pressure on the lid and blows it off, painting the walls and ceiling with krausen. When the yeast are consuming the sugars of the beer they expel a large amount of CO2 and like to scavenge oxygen to help them create new yeast cells. I often make a 2 1/2 gallon batch and ferment it in a 6.5 gallon fermenter. That way I know the krausen won't reach the lid.

 

[Broken Crow]

No, he means more headspace. The amount of headspace only really matters when it isn't enough and your krausen puts pressure on the lid and blows it off, painting the walls and ceiling with krausen. When the yeast are consuming the sugars of the beer they expel a large amount of CO2 and like to scavenge oxygen to help them create new yeast cells. I often make a 2 1/2 gallon batch and ferment it in a 6.5 gallon fermenter. That way I know the krausen won't reach the lid.

Yes! Exactly that... Here's what happened long ago when I put 5-gallons of wort into a 5-gallon carboy to ferment:
(the ceiling even today, over my laundry-room washtup where I rushed my barfing carboy) :

 

[VikeMan]

using PET means you can see what's going on, and that's nice and all, but the more important reason is that PET is way less oxygen permeable than hdpe.

This is true, but there's more to the story. Popular HDPE fermenters (such as Speidel) tend to be much thicker than popular PET fermenters (such as Fermonster).