Degassing

[Grump]

Without sifting through threads and searching; I'd like to pose a question. I'll restrict my question to Melomels and use the term 'secondary' meaning the original fruit and any additives have been (mostly) removed. With the understanding that there will be those that disagree with the term 'secondary', please allow it for the sake of discussion.

Do you de-gas in the secondary? If so, how often and what determines when you do so? If you do not, why not?

For instance, I de-gas in the secondary and do so (generally) as the SG drops a certain number of points. My thinking is that as it is fermenting, it benefits from de-gassing.

I expect that this should be the norm, but am interested in other perspectives.

 

[CKuhns]

I only de-gas in an effort to correct a ferment that has stressed the yeast and produced a sulfur smell and not as a routine practice. I would do so only after fermentation is complete and after all additives are removed.

If I have a nice clean ferment with no perceptible off flavors or smell, then de-gassing is not something I feel is necessary.

Great question - I will be interested to hear how others answer.

 

[Yooper]

I degas in primary, only- sort of. When I make a wine or mead with fruit, I stir as often as I think about it, to break up any cap that as formed, as the c02 pushes the fruit up to the top. That's only for about the first 4 or 5 days, and then after I rack to secondary and top up, I avoid oxygenation at all costs.

 

[BudNini]

How about when adding nutrients? I have read you should stir the must just before adding your nutrients to avoid explosions.

 

[Amadeo38]

If the point of de-gassing is to remove yeast-harming co2 from solution, then to me, it only makes sense to do it when: A) there is a lot of yeast in suspension, and B) there is a lot of co2 in solution. The only time this is the case is during primary, so that’s the only time I degas. After that, why risk the oxidation?

 

[Yooper]

How about when adding nutrients? I have read you should stir the must just before adding your nutrients to avoid explosions.

Yes, because adding things creates nucleation points for the co2, and you can get a major volcanic eruption in a gassy mead or wine when you add nutrients.

 

[Grump]

Just to clarify (probably unnecessary because it sounds like everyone is tracking), but I'm not referring to Aerating. Done correctly there should be no (almost no) risk of oxidation. As long as there is carbon dioxide flowing outward, there's little chance for O2 to get in (high pressure vs. low pressure).
Amadeo is spot-on. My reason for degassing is primarily (almost entirely) to remove CO2 that remains in solution. With an active fermentation (especially with certain yeasts) that can be an impressive amount of gas.
I use a lee's stirrer on a drill, and on occasion I find myself wishing for a little more headspace in the jug. I have heard of others using a vacuum pump to draw out gas in solution. Personally, I have no experience with this.

 

[Mtrhdltd]

This is a great question, and has me thinking. As Yooper said, I degas as im breaking up the fruit cap, or before nutrient additions. Once im out of the primary I just leave it alone and wait patiently. Now you have me wondering if I should be degassing later in fermentation.

 

[bernardsmith]

I've use an aspirator vacuum pump to degas and they work well but you really need to be careful and use a second (small) vessel as a trap between the carboy you are degassing and the pump because it is possible that the pump will suck up mead or wine if not properly aligned) and the liquid will damage the pump.

 

[Rish]

Dr. Bray Denard, originator of the BOMM, says to degass daily until 2/3 of the sugar is fermented to reduce acidity caused by CO2 build up, making your yeasties happier.