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DaveVanO 01-27-2013 04:23 AM

Question about Primary Fermentation+Oxygen
 
Do most of you leave your carboys/fermenters uncovered for a day or two using cheesecloth or something of the sort to allow oxygen to your yeast? I have read that some do this. But I have yet to do it. Just trying to figure out different ways to make mead and all the different procedures.
So far I have made 4 meads and all are clearing/aging. Only reason is that almost all of them finishied in a week of fermenting beginning. I didnt allow oxygen to the must. Just added honey+everything to the primary carboy, shook it really good until looks all mixed, then pitched yeast/nutrients/energizer, and a quick swirl. Stopper+airlock.
Any opinions on my procedure, so far i havent grabbed SG from the 4 batches, and all 4 after 1 weekish (5-8 days) were at 1.000. 3 of which were different variations of JQGM and the last one was a raspberry/blackberry melomel. (by the way, will this start smelling better? I racked today to a secondary for clarity+aging. and it smells a bit weird..)
Cheers
-Dave:mug:

fatbloke 01-27-2013 08:47 AM

Quote:

Originally Posted by DaveVanO (Post 4831220)
Do most of you leave your carboys/fermenters uncovered for a day or two using cheesecloth or something of the sort to allow oxygen to your yeast? I have read that some do this. But I have yet to do it. Just trying to figure out different ways to make mead and all the different procedures.
So far I have made 4 meads and all are clearing/aging. Only reason is that almost all of them finishied in a week of fermenting beginning. I didnt allow oxygen to the must. Just added honey+everything to the primary carboy, shook it really good until looks all mixed, then pitched yeast/nutrients/energizer, and a quick swirl. Stopper+airlock.
Any opinions on my procedure, so far i havent grabbed SG from the 4 batches, and all 4 after 1 weekish (5-8 days) were at 1.000. 3 of which were different variations of JQGM and the last one was a raspberry/blackberry melomel. (by the way, will this start smelling better? I racked today to a secondary for clarity+aging. and it smells a bit weird..)
Cheers
-Dave:mug:

Picture a poorly made TV programme about dubious science or scientists. They always seem to have a beaker that is producing small clouds of white looking gas or steam.

Well that's "dry ice", probably in water. You follow ?

Now with a fermentation, there's no dry ice, but there is water, fermentable sugars, yeast etc. It just happens that it's the yeast munching the sugars and producing alcohol and CO2.

So as the reaction of the fermenting honey must, produces the CO2 a lot slower than the dry ice in water, it doesn't make whats observable any different i.e. instead of seeing clouds of white gas bubbling up and flowing over the sides of the beaker, it's still doing the same thing i.e. displacing any air that was above the liquid surface originally, the CO2 is still making a layer that will lift up the air and it will flow away as the CO2 starts to flow out over the top of the beaker, or open topped fermenter in this case.

That's all presuming that the batch is kept away from any draughts or breeze that has a high enough pressure to blow/wash the CO2 away from the surface of the fermenting must.

Which is why you can indeed leave a ferment open, or covered with a fine cloth of some sort, which would keep out any bugs and larger sized dust, but still allow any fine dust or smaller type materials to pass through the cloth. It would be hoped that the positive pressure of CO2 might exclude such fine materials, but not guaranteed.

Equally, you need to provide the draught, breeze or kind of pressure to remove any built up layer of CO2 as any dissolved oxygen in the liquid will likely have limited effect, and need augmenting. Hence the suggestion of shaking, bubbling air, stirring vigorously or even bubbling pure O2 through the mix is what is suggested/recommended.

Of course, that's not to say that a batch that is just left covered loosely, whether with a cloth, a bucket lid, etc won't make good mead is wrong. People seem to just do it like that with no ill effect, but I'd still say it's best to agitate or bubble air/O2 through the mix for the greatest effect and benefit to the yeast.......

p.s. and personally, no I don't leave any batches open to the air. Yet I'm happy to agitate/stir with a sanitised electric balloon whisk if there's no "bits" to chop up/break down. If there's fruit etc, I just remove a pint or two and blitz it in a sanitised liquidiser and return it back to the batch. To no ill effects so far.......

Inner10 01-27-2013 01:03 PM

I do, and to be honest it was because that's the way my grandfather did it.

fatbloke 01-27-2013 03:56 PM

Quote:

Originally Posted by Inner10 (Post 4831748)
I do, and to be honest it was because that's the way my grandfather did it.

There's many legacy type techniques that just work. Either way, CO2 is heavier than air/O2 so unless the batch is left somewhere where a draught or breeze can get to it to shift the CO2, then it'll still blanket the batch, and possibly allow in spoilage organisms.....

S'up to you really.....

DaveVanO 01-27-2013 04:56 PM

alright, so just me shaking the batch a little to stir up the ingredients would do the trick. Its what ive been doing since making them. Id just shake it a little bit and of course the airlock does bubble when i do it. So i guess ive been doing the trick a little bit

TheBrewingMedic 01-27-2013 05:31 PM

You're on the right path. I never leave mine open or loosely covered because really im just paranoid, not of a wild yeast or infection as much as dust, pet hair (2 dogs, 3 cats, pet hair finds its way into everything if not careful), or some type of crawly critter finding its way in. So I airlock from the begining, pop it off 2-3 times a day during the first 1/3 of fermentation, I let it sit in a bowl of starsan while I do this, and use my mixer to give first a gentle swirl to get the CO2 in suspension out then more vigorously to complete that process and get some fresh air (O2) in to the yeast. I also have 100% O2 and a ss airstone that I give it a little extra jolt from but that's just because I'm lucky enough to have access to it. Some call it degassing, others aeration, choose your term and go with it, either way it's a method to manually assist an exchange of gasses, young yeast like the fresher O2 over the heavier acidic CO2.

DaveVanO 01-27-2013 06:20 PM

If i made a yeast starter. added it to the must, but the must wasnt completely lowered in temp. Like id say it was around 80*F. Would this hurt the yeast? Or should I have waited until it was lower. It might have been a bit higher, And, will it show signs right away of fermentation when its added to the must?
Or would the heated must shock the yeast and the starter wouldnt of mattered?

First time using a yeast starter and I did a whole packet of yeast+must, nutrient, energizer, mixed it all together. covered and let it sit for 15-20 mins. It started right up and was filling the cup of the starter.
SG:1.105 with 1116 yeast

Inner10 01-27-2013 06:50 PM

Quote:

Originally Posted by DaveVanO (Post 4832682)
If i made a yeast starter. added it to the must, but the must wasnt completely lowered in temp. Like id say it was around 80*F. Would this hurt the yeast? Or should I have waited until it was lower. It might have been a bit higher, And, will it show signs right away of fermentation when its added to the must?
Or would the heated must shock the yeast and the starter wouldnt of mattered?

First time using a yeast starter and I did a whole packet of yeast+must, nutrient, energizer, mixed it all together. covered and let it sit for 15-20 mins. It started right up and was filling the cup of the starter.
SG:1.105 with 1116 yeast

I'd say 80F is just fine.

TheBrewingMedic 01-27-2013 06:57 PM

Quote:

Originally Posted by DaveVanO (Post 4832682)
First time using a yeast starter and I did a whole packet of yeast+must, nutrient, energizer, mixed it all together. covered and let it sit for 15-20 mins. It started right up and was filling the cup of the starter.
SG:1.105 with 1116 yeast

This sounds more like an amped of method of rehydration , I use kind of a similar technique, than a starter which takes hours to days to make.

generally the rehydration temp, if you looked at the package instructions state 104*F-109*F and optimal pitch temp around 80*F-90*F so you should be fine

don't expect fermentation to look like it starts immediately, it may be quick, like within a few hours or a day, but it won't be visibly or aubibly noticible right away. figure the ratio of yeast to liquid in your rehydration cup verse in your fermenter, the yeast has to work a little to get the bubbles flowing.

DaveVanO 01-27-2013 08:37 PM

Ok thanks. Yea idk exactly how to make a starter, kinda winged it and looked at the rehydration stuff on the back of the yeast and went from there. Thanks for the input. Hopefully it wasn't too warm and works fine.


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