Re: De-Gassing

[gbing]

So, is degassing a mead daily during the first week of primary an essential "must do" kinda thing?
Can anyone tell me of the benefits of doing so, or point me towards some reading?
None of my homebrewing books talk about it ( mind you, their emphasis is beer-making) and haven't found anything on HBT about it (yet!)

It just feels weird to do it, and it contradicts everything I've learned while making beer....

Thoughts?

 

[Maylar]

Not a "must do", but it's part of the latest knowledge base / best practices and contributes to a cleaner ferment that leads to mead that can be consumed with less aging time. I never heard of it either 'till I started hanging out at the gotmead forum.

I think the wine makers do it too. And mead isn't beer -

 

[fossilcat]

Honey, and by extension the must, has a hard time buffering. The more CO2 in solution, the more acidic your must. Yeast doesn't like an acidic environment - an unhappy yeast may not produce the best results. So we do things like add potassium carbonate and degass to keep the must pH above 3 or so.

Also, there is a difference between degassing and adding oxygen to your must. To oxygenate your must you agitate vigorously by shaking, stirring aggressively, or using a lees stirrer with drill. Oxygen is important to the growth of the yeast colony but should be curtailed around the 1/2 sugar break when bad stuff that I can't remember right now starts happening if you continue. All I know is that at this point the alcohol level approaches a point here where oxidation becomes a concern.

At this point you reduce your must agitation and frequency so the CO2 bubbles are released without introducing O2. I taper off the aggressive stirring until the 1/3 sugar break and then just swirling the container occasionally from there on.

I'm not a beer brewer but I think you have to be more careful about oxidation with beer. Mead overall is more forgiving.

 

[bernardsmith]

My understanding is that you can stir the must to introduce oxygen until there is very little sugar remaining for the yeast to ferment. The yeast need O2 to replicate so during the early part of the process you want to assist the yeast. When all the sugar has been consumed you are less interested in the yeast's ability to reproduce and the fact that CO2 production will also have ceased means that adding air will lead to the deterioration of the wine.
Stirring the must when in the primary also ensures that the yeast is distributed evenly throughout the fermenter. Failure to stir the must can mean that the yeast will tend to settle in layers up and down the carboy and that may inhibit a smooth fermentation. This may be less of a problem when you are fermenting 5 or 6 gallons but the taller the fermenter and the larger its volume the more you may need to ensure proper distribution of the yeast.
The other reason for stirring (degassing) is that if you are fermenting anything with fruit solids you may need to stir the must to ensure that all the fruit remains suitably soaked. Allowing the cap to dry out can create two problems - the first is that the fruit cap can prevent CO2 from being expelled and so pressure builds up until the gas blasts its way out of the fermenter taking the fruit and much of the must with it. The other problem is that even if there are enough openings in the fruit cap to allow the CO2 to escape, that fruit as it dries on the top surface then becomes a haven to bacterial and other spoilage... so you want to make certain that it is always macerating in the must /wine - and you do that by stirring. All that said, my preference is to consider what you do as "stirring" and not "degassing" since only about 1 out of 4 reasons for the stirring is to degas...