How full should you fill a 6.5G carboy?

I have a beer that I ended up with about 6 gallons instead of the projected 5.5G. I am not positive if my carboy is 6 or 6.5G, but my beer is only a few inches from the top and well up on the slanted part.

I have had my starter going and am going to pitch it tonight. I am switching over to a blow-off tube for this (1/2 in ID) but was wondering if I should expect some fireworks or anything.

P.S. this is a 1.0645 OG beer and a 1000ml starter

You are going to have a lot of blow off. People use a 6 gallon carboy for a 5 gallon batch and have some blow offs. That is cool that you hit your OG and had the extra gallon though.

Mirage said:

You are going to have a lot of blow off. People use a 6 gallon carboy for a 5 gallon batch and have some blow offs. That is cool that you hit your OG and had the extra gallon though.

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Yeah, it is the first time I have gone over my final volume and by far the most I have put in the carboy. I just didn't want to waste that precious beer. Anyways, I am just hoping I don't find a rubber stopper on the other side of the room after it shoots off or something.

You should rig it with a blow off now. Your stopper will be gone and some of your beer. LOL, that will be a crazy bad mess.

I add the anti-foam agent Fermcap S to my carboys. Most times I can fill them to within an inch of the neck and not have a blow off. I do like to ferment my beers on the cold side of the yeast range so that helps too.

I've got a 5 gallon batch in a 5 gallon carboy, and its blowing off like a mother-effer right now. Big mess (good thing I ferment in an extra shower) and I know I'm losing a bit of my beer, I might end up with 4-4.5 gallons when all is said and done, after the amount of blowoff I'm having.

I'd say, add as much as you can (anything you dump is guaranteed lost beer) comfortably, then let it blow off whatever it will and you'll get the most beer you can out of it.

pjj2ba said:

I add the anti-foam agent Fermcap S to my carboys. Most times I can fill them to within an inch of the neck and not have a blow off. I do like to ferment my beers on the cold side of the yeast range so that helps too.

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That is good to know, I have never heard of that stuff. I pitch the yeast when I went to bed last night with a 1/2 inch blow-off tube. There were the smallest bubbles around the sides this morning so I should see some action when I get home today.

I am also fermenting at 65 which is the lower end of WLP002 which is the low of its range and I will probably put it up a degree or 2 slows down a bit. It is in a water bath with an aquarium heater right now so I don't think it should go too far above the ambient temp.

Many yeast will ferment just fine at temps below the "ideal". I've got an IPA brewing now that went gangbusters at 62 F even though the listed ideal temp range for the yeast I used is 68-73F

pjj2ba said:

Many yeast will ferment just fine at temps below the "ideal". I've got an IPA brewing now that went gangbusters at 62 F even though the listed ideal temp range for the yeast I used is 68-73F

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That is a good point. I know notty goes down low and pacman at 60 too. I believe they claim these temps on the packages though.

I want to get more fruity esters out of this beer though as I will be doing a secondary on top of raspberries so I might bump it up a little, but the fermentation should do the heating for the next couple of days.