Secondary fermenter: how much headspace?

[Brewer393052]

Hi, one of the 5-gallon recipe I have calls for a secondary fermentation in a different vessel, with dry hoping. As I don't have a 5-gallon glass vessel (looks like plastic is not recommended because of O2 permeability), I was thinking I'd use the 2 1-gallon glass fermenters I have.

In terms of capacity, each of those fermenters can hold a bit more than 1.5 gallon. Because it's a secondary, I understand headspace should be small to limit O2 exposure. With 1.25 gallon, the surface of the liquid is 3 inches below the lid. With 1.5 gallon, it's 1 inch below.

My question is: how much headspace is too much and how much is too little for a secondary? In other words, how much beer can I put in those fermenters? 1.25 gallon? 1.5?

Thank you

 

[BrewnWKopperKat]

recipe I have calls for a secondary fermentation

Can you post the recipe / style?

In the early 2020s, the "early 2000s (1990s?)" home brewers concept of "secondary" is generally not necessary.

 

[Brewer393052]

Can you post the recipe / style?

In the early 2020s, the "early 2000s (1990s?)" home brewers concept of "secondary" is generally not necessary.

Steps 17-19 in the attached PDF file

 

[Broken Crow]

It sounds like you're working with minimal equipment and probably looking to do a siphon or gravity transfer with no bottled CO2 for purging anything. The transfer alone is likely to introduce far more oxygen than any O2-permeated-to-plastic.... You'd probably be best off just quickly and carefully pulling your airlock, dumping the hops in putting the airlock back in (after wiping with a sanitizer). Like @BrewnWKopperKat said; Secondary is an uneeded and risky thing of the past.

 

[BrewnWKopperKat]

@Brewer393052 : With a session IPA, you need to minimize transfers between containers.

@Broken Crow offers solid advice on the dry hop addition.

eta: FWIW, this is one of the extract few online kit instructions that I have seen that does not make secondary optional. This seems like the time and place to make use of the vendor's customer support and "We've Got Your Batch" guarentee.

 

[Brewer393052]

FWIW, this is one of the extract few online kit instructions that I have seen that does not make secondary optional

To be fair, they do mention that the secondary is optional, in the "Minimum requirement" section:

"A 5 gallon glass carboy, with bung and airlock, to use as a secondary fermenter - If you do not have a secondary fermenter you may skip the secondary fermentation and add an additional week to primary fermentation before bottling"

 

[Brewer393052]

It sounds like you're working with minimal equipment and probably looking to do a siphon or gravity transfer with no bottled CO2 for purging anything. The transfer alone is likely to introduce far more oxygen than any O2-permeated-to-plastic.... You'd probably be best off just quickly and carefully pulling your airlock, dumping the hops in putting the airlock back in (after wiping with a sanitizer). Like @BrewnWKopperKat said; Secondary is an uneeded and risky thing of the past.

Yeah, I'm going back and forth between doing a secondary or skipping it. What I was envisioning was transferring via gravity (spigot + tubing) carefully in the glass fermenters, roughly 2.5 gallons of the batch, and bottling the remaining 2.5 gallons. The added benefit would be that I could compare the 2 sub-batches and judge what the impact of the secondary was. But as you said that might be a lot of trouble and risk for not much added benefits.

 

[Broken Crow]

Yeah, I'm going back and forth between doing a secondary or skipping it. What I was envisioning was transferring via gravity (spigot + tubing) carefully in the glass fermenters, roughly 2.5 gallons of the batch, and bottling the remaining 2.5 gallons. The added benefit would be that I could compare the 2 sub-batches and judge what the impact of the secondary was. But as you said that might be a lot of trouble and risk for not much added benefits.

Yeah..skip it for now. IPA's and other hop-forward brews are particularly prone to O2 damage. If you want to do a splitting experiment for your own comparison, I'd recommend a traditional low-hop English-Ale, In my own experience, I've found some of them actually taste a bit better with a miniscule amount of oxidation, but you can still taste it and that helps to 'educate & inform' your palate and brewing sense. All part of the journey.
Brew On!

 

[PokerDad]

I agree with the commenters who recommend skipping the transfer and the secondary fermentation. I have made only 2 batches of beer so far, both from kits, and both with instructions that "recommended" secondary. For the first batch I did the secondary, and for the second batch I skipped it. Much better flavor on my second batch, for what it's worth. And the second batch also included dry hopping. Based on advice from this forum, I just quickly lifted the lid off my white plastic bucket fermenter, tossed in the hops, and sealed it again. I don't think I even bothered to stir them in. Again, I thought the results were fine, but of course I'm a beginner, what do I know? Good luck!