View Full Version : airspace in the carboy after racking

09-20-2005, 06:28 AM
Hello all, I have my first batch going, inside a carboy similar to this:
www.testimonigeova.com/ruben/carboy.jpg (http://www.testimonigeova.com/ruben/carboy.jpg)
Since there is some airspace in the carboy, and I want rack into an identical carboy, for secondary fermentation I was wondering if the air will be a concern.
The primary fermentation is almost done but is still going a little. I guess if I rack now the CO2 developing should replace the air (and oxygen) inside the new carboy preventing oxidation. But if the fermentation is very slow, do you think it would be a concern as to the airspace and oxidation?
Thank you,

Dan McFeeley
09-20-2005, 06:33 AM
It should be alright, so long as there is still active fermentation. Keep an eye on it -- racking off the lees removes a large portion of the yeasts from the fermentation and may slow things down to an almost unnoticable trickle.

09-20-2005, 09:33 AM
Here's a question I've been wondering about, but haven't seen addressed:

when racking, how do yall make up for the lost space?

at this point, i've taken to making about 20% more than my recipe calls for, then refrigerating the excess when going from primary to secondary. that way, at any subsequent rackings (with that batch, or others based on the same honey), i can top off from the extra refrigerated stash.

however, i was wondering whether anyone had approached the issue from another perspective: taking a cue from Archimedes, and adding things to the carboy in order to help fill the volume lost?

really, i was thinking that glass marbles would be a reasonable material for this; but the real question is: is this approach worthwhile, or should i just always keep a stash of emergency must on hand?


09-20-2005, 10:56 AM
Some times, I make 20% - 25% more must and keep it cold for topping up after racking and to feed the mead to briing the abv up.

A couple folks I know use 3/4" solid Acrylic sphere's (it would be a shame to dump a batch, due to a chipped marble). The only time I really even think about headspace is during primary when it may over flow and during aging, when theres no co2 being produced.


09-20-2005, 03:16 PM

A lot of us rack down, we start with a 6.5 gallon carboy, rack down to a 6, then down to a 5. Rack to a 5 late enough and you have some damn fine spillage. ;D I usually rack just before fermentation has stopped so the last carboy will still generate some CO2 to blanket the top.


09-20-2005, 03:26 PM
I have two bottles of CO2 I start in a 6.5 and rack to another 6.5 and allow for secondary fermentation if any occurs. I flood the vessels I rack to with CO2 in order to keep oxidation from becoming an issue.

I go back and blanket the carboys once a month to be sure there is ample CO2 to keep my babies safe.



09-22-2005, 12:18 PM
I have 4oz and 12oz co2 tanks for my paintball gun. Should I just fill up a ballon and then let it loose on the carboy? I could just straight push the tab and send some in? What about cleaning the gun and shooting some in (hee hee hee)? Any other ideas?

09-22-2005, 12:29 PM

DON'T use the CO2 tanks from your paintball guns! They may look the same as the kind sold for the homebrew market, but they have minute amounts of solvents and oils in there to help keep the mechanical parts of the machines they typically go into working well, and these will ruin your mead. They make a small gun thingie just for squirting CO2 into homebrew fermenters, and I think it goes for pretty cheap.


09-22-2005, 01:29 PM
I am not sure about there being oil in the paintball gun CO2...I have never notice any oil in mine. However, keep in mind that the paintball cannister is filled with liquid-phase C02, not gas-phase. Pushing the little pin in is not a good idea. You will have raw CO2 spewing everywhere creating a potential Darwin Award situation.


09-22-2005, 04:27 PM
Here's a link that lists the criteria for food-grade CO2. It doesn't mention oils specifically, but I think that they might fall under the heading of "Nonvolatile organic residue". Food grade CO2 is a byproduct of the food processing and beer/wine industries, but not all CO2 is required to be this clean, and can therefore be derived from other industrial processes.