6 or 6.5 gallon carboy

[businesstime]

I got a 6 gallon carboy with a new kit that I purchased. I decided I wanted to get a second one for secondary fermentation. However, now that I have 2 6-gallon carboys I wonder if I should have got a 6.5 for primary.

Will a 6-gallon carboy be large enough for the primary of a 5-gallon batch? Will I be ok if I use a blowoff tube for the first few days of primary fermentation?

 

[buzzkill]

6.5 is better,but with a blow off tube its good. ( the 6.5 gal are harder to find these days)

 

[MurderMittenBrewing]

Keep in mind that the rated volume of a carboy is going to be lower than the actual volume. A "6 gallon" carboy is really closer to 6.5 gallons.

That said, if you can find a 6.5 it's not going to hurt. I've had no problems with my 6 gallon used as a primary... I just use a blow off tube for the first few days.

As far as using the 6 gallon for a secondary, there's an argument to be made that you'd actually want to use a 5 gallon as to minimize the headspace. Feel free to use this as an excuse to buy more carboys

 

[Malticulous]

For a long term secondary you don't want any head space. Get a five.