Headspace in 1 gallon jug?

[optaka]

Going to be doing some one gallon batches for the first time and I'm not sure how much head space I need to leave. I filled a jug with one gallon of water to see where that puts me and it looks pretty darn full.

Is that going to be enough space or should I go a bit lower? I will be picking up some fermcap from my LHBS if they have it, but what would you guys suggest as space needed with and without fermcap?

 

[MrBrown]

There should be a raised lettering that says one gallon. Fill it to that mark and it should suffice for headspace. Anything more and you might have a loss when the krausen forms.

 

[Calichusetts]

Going to be doing some one gallon batches for the first time and I'm not sure how much head space I need to leave. I filled a jug with one gallon of water to see where that puts me and it looks pretty darn full.

Is that going to be enough space or should I go a bit lower? I will be picking up some fermcap from my LHBS if they have it, but what would you guys suggest as space needed with and without fermcap?

I'm not sure how you measured but the 1 gallon mark is the top of the gallon etching, you appear a bit higher. I fill to that mark and usually don't have issues unless I use notty or some aggressive yeast. I always have a blow off tube but I usually ferment very low, 58-60 as I like cleaner beers and of course less blow off

 

[optaka]

Measured with a 4 cup measuring cup 4 times. Did it again with a different measuring cup and you appear to be correct, comes out at the very top of the "one gallon" stamp. So filling to that point should provide me with enough head space for everything but Notty? I doubt I will end up that low on fermentation since it will be sitting in a swamp cooler in my living room/dining room/office in my tiny apartment but I will add some fermcap to hopefully keep things down. Thanks for the advice

 

[Calichusetts]

Measured with a 4 cup measuring cup 4 times. Did it again with a different measuring cup and you appear to be correct, comes out at the very top of the "one gallon" stamp. So filling to that point should provide me with enough head space for everything but Notty? I doubt I will end up that low on fermentation since it will be sitting in a swamp cooler in my living room/dining room/office in my tiny apartment but I will add some fermcap to hopefully keep things down. Thanks for the advice

It depends, its not just notty or other violent yeasts...its also your OG. The higher it gets the more work the yeast does and the more krausen you get. Its no big deal if it blows out but I would have a tube on for the first few days. The reason I try to avoid it is sometimes the krausen actually forms a seal under my cap and I have to break through it to siphon, getting tons of gunk in my relatively clear beer