One gallon recipe question

[Hedley]

Hi Brewers,

I am looking to do my first all-grain brew, using a 1 gallon recipe. Will it be okay to ferment in my 3 gallon fermentation vessel? (Just concerned there will be a lot of room for air in that).

Any help most appreciated.

Ross

 

[IslandLizard]

If you can leave that larger vessel closed [Edit]with an airlock[/Edit] until you're ready to package the beer, it should be alright.

Reason is, during fermentation the headspace will become rich with CO2, preventing oxidation problems later on. As soon as you open it, that CO2 starts to dissipate.

What kind of beer is it?
How long do you think the beer will stay in that fermentor?

 

[homebrewer_99]

As long as the yeast (and airlock) is active the CO2 will be pushing the air out...

 

[Reavers2013]

Should be fine. CO2 is denser than air so any co2 produced with likely lay as a bed on the wort. You can also get some glass beads, sanitize them, then add them to make it so your volume is artificially larger leaving less head space.

 

[IslandLizard]

Should be fine. CO2 is denser than air so any co2 produced with likely lay as a bed on the wort. You can also get some glass beads, sanitize them, then add them to make it so your volume is artificially larger leaving less head space.

Sad to say, the CO2 blanket is a myth. Gas laws together with turbulence will start mixing the headspace CO2 with surrounding air as soon as you open the fermentor or remove the airlock. Now a narrow carboy neck will provide a little bit more protection than removing the lid from a bucket or the fairly large lid of a Fermonster, Big Bubbler, etc.

A gallon of glass beads is a lot. They're also very heavy, beware!

 

[Hedley]

Thanks all,

It is a session IPA. This recipe:
https://www.beercraftr.com/1-gallon-session-ipa-recipe/

It will stay in that fermentor for about 2 weeks, when I will siphon into bottling bucket and bottle.

I do have a glass 1 gallon carboy but that isn't going to allow room for dry hopping, hence my plan to use larger fermentor.

Ross

 

[AkTom]

If it was me. I’d use the 3 gallon carboy. Dry hop at day 5. Keep the airlock on till day 14 and bottle. Don’t forget FG.
Normally I’d offer to help you drink a couple, but seeing as it’s a gallon, it’s all on you.
Cheers

 

[IslandLizard]

Yeah, you need to allow some headspace for krausen and dry hops later. Larger headspaces aren't usually a big problem unless you leave it in there for weeks or months. Just clean and sanitize the inside of your fermentor well.

2 weeks is fine it should be done by then, possibly earlier. You're planning to dry hop 5 days before packaging?

What kind of fermentor is it? Large lid?

 

[Reavers2013]

Sad to say, the CO2 blanket is a myth. Gas laws together with turbulence will start mixing the headspace CO2 with surrounding air as soon as you open the fermentor or remove the airlock. Now a narrow carboy neck will provide a little bit more protection than removing the lid from a bucket or the fairly large lid of a Fermonster, Big Bubbler, etc.

A gallon of glass beads is a lot. They're also very heavy, beware!

Glass beads are heavy and the headspace should be fine but a good fix if you are really worried.

Gases like CO2 and air dont mix very well (hense carbon monoxide risk from brewing indoors). If you rock the carboy you for sure can mix the gases but general with short exposure the amount of air is negligible. The diffusion coefficient of O2 into CO2 is low given the difference of these two gases and remember oxygen is only about 30% of the air around us.

 

[Hedley]

The recipe says to dry hop for 4 days, so I'll dry hop at day 10.

My 3 gallon fermentor is the large tub type with large lid. I've used it to dry hop before - just peeling back the lid a popping the hops in, and I don't think oxidation has been a problem. That was with a 2.5 gallon batch, but I am guessing there is not too much extra risk using this for a 1 gallon batch. The surface area is obviously the same.

As an aside, I have never seen the air lock actually bubble. The lid swells up for the fist few days (and if I press it down the airlock bubbles), and I get the foamy stuff happening. I think someone on here said not to worry and that not all set ups bubble.

 

[IslandLizard]

The recipe says to dry hop for 4 days, so I'll dry hop at day 10.

My 3 gallon fermentor is the large tub type with large lid. I've used it to dry hop before - just peeling back the lid a popping the hops in, and I don't think oxidation has been a problem. That was with a 2.5 gallon batch, but I am guessing there is not too much extra risk using this for a 1 gallon batch. The surface area is obviously the same.

As an aside, I have never seen the air lock actually bubble. The lid swells up for the fist few days (and if I press it down the airlock bubbles), and I get the foamy stuff happening. I think someone on here said not to worry and that not all set ups bubble.

It's strange how the lid swells, apparently sealed well enough to hold that pressure, but the bubbler doesn't bubble normally without pushing the lid down. Make sure there's no restriction in the bubbler. I had something similar where the bucket lid would bulge like crazy and then suddenly release the pressure all at once through the 1/2" ID blowoff tube into the jug with sanitizer. It was like a breathing wild animal.

Many lids don't seal well enough, so the gas escapes through the voids. That's fine.

I've modified some bucket lids by drilling a second hole in them (1" diameter) to give me access for adding dry hops, etc. without lifting the lid. If I could only remember to put those on before I need the access...