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Honey
04-04-2012, 07:37 AM
Okay - Do I have this right...

At must-making one wants to shake the carboy like a dog with a rag doll to get as much air mixed into the must as possible, then pitch in the yeast.

When one transfers into secondary ferment carboy one wants to insert a "stirer" or mixer and mix again, but this time to get the air OUT not IN... and since it seems to be rather the same action, one just does it very gently so as to not have the opposite result of actually getting more air IN???

And stabalizing the brew is adding chemicals to make sure bottle bombs are no worries and this is done a day or so prior to bottling.

Do I have that right?

Honey

Bob J
04-04-2012, 07:48 AM
Yep, the yeast need oxygen early in their life cycle (to rapidly reproduce) so the early agitation prior to pitching is to get as much oxygen in the must as possible..... Later in their life cycle the CO2 in solution becomes somewhat toxic to them so the later degassing is specifically to help them with that..... In the later stages of fermentation you also want to be careful that you don't introduce too much oxygen as there is a risk of oxidation which will affect your mead's flavor....

TAKeyser
04-04-2012, 08:53 AM
You can add oxygen into your must during fermentation usually up to the 1/3 sugar break (ie if Original gravity was 1.100, the 1/3 break is when gravity falls to 1.066) this will insure proper yeast health. You'll also degas during primary fermentation as this is when the most CO2 (a byproduct of fermentation) will be in the must, this can be done with a spoon, stick blender, swirling the carboy with the airlock still on, etc. Stabilizing can be done at anytime, for example if you want to stop fermentation at a certain gravity to retain some residual sugars for sweetness. I usually stabilize when I rack for long term bulk aging.

fivecats
04-04-2012, 10:28 AM
Okay - Do I have this right...

At must-making one wants to shake the carboy like a dog with a rag doll to get as much air mixed into the must as possible, then pitch in the yeast.

When one transfers into secondary ferment carboy one wants to insert a "stirer" or mixer and mix again, but this time to get the air OUT not IN... and since it seems to be rather the same action, one just does it very gently so as to not have the opposite result of actually getting more air IN???

And stabalizing the brew is adding chemicals to make sure bottle bombs are no worries and this is done a day or so prior to bottling.

Do I have that right?

Honey


Keep in mind you're talking about two entirely different things. The former is all about providing the best environment possible for your yeast to thrive, multiply and do their converting-sugars-to-alcohol thing. The latter is all about stopping the yeast from doing their work.

Since yeast need oxygen early on, you need to get oxygen into the must. Shaking, stirring vigorously, etc., will all work. I think it's a homebrewer's preference as to what works best/easiest for you.

When you're bottling, you're transferring the must from one vessel to another. This action alone can be enough to 're-awaken' some of the yeast in your solution. If enough of those yeasties start to work again, you can create bottle bombs. "Stabilizing" is, indeed, adding chemicals to the must to inhibit yeast cells from being able to reproduce and, therefore, eliminating any potential bottle bombs.

Your subject heading, however, is "Degassing" which you actually don't address here. While your yeast is doing its work it's also creating a lot of CO2. That CO2 sits at the bottom of the fermenter and getting rid of it typically makes for better mead. With the batch of mead I'm making now (http://www.gotmead.com/forum/showthread.php?t=19591), I started degassing 24 hours after I noticed that fermentation had started.

To do so, I opened the fermenter and used a stick blender to stir up the must. I gave my stick blender a quick pulse and the release of CO2, in the form of fizzing, was instantaneous. I kept pulsing the stick blender until there was no more fizzing coming up from the bottom of the fermenter. (That took all of two minutes or so) Then I reattached the lid to my five-gallon fermenter bucket, repositioned the airlock and left it alone until the next day. I've done this for three days in a row (adding some yeast nutrient after degassing, btw) and now I'm done.

I won't touch the must again until fermentation has stopped for a week or so. At that time I'll rack it into a secondary and let it age with some OJ, orange zest and vanilla beans.

Hope this helps!

TAKeyser
04-04-2012, 11:53 AM
"Stabilizing" is, indeed, adding chemicals to the must to inhibit yeast cells from being able to reproduce and, therefore, eliminating any potential bottle bombs.

Oh how I hate the word CHEMICALS it makes it sound like they are some invented ingredients. The "chemicals" are naturally occuring elements so you're not adding unnatural or artificial ingredients into your meads. Sulfites are a byproduct of the fermentation process and sorbates I believe are naturally occurring in honey (don't quote me on that though), you are just bumping up the levels to be beneficial to your must. In addition to stopping you yeast so you don't get bottle bombs the addition also has the benefit of slowing down oxidation to give your meads a longer shelf life.