[sandmanxy]

I just started my first batch 24 hrs.ago. The guy at the wine supply store told me to cover it with a lid and put an air lock on it as oxygen was necessary for yeast reproduction only. Do the yeast only produce alcohol during anerobic fermentation,or is an aerobic environment a necessary condition? I am just a newbie at this and could use some advice.

[Sacalait]

The presence of air is a necessary part in the primary fermentation stage. Once the SG drops to 1.02+/- then the must is racked to a corboy (secondary fermentation stage) and fitted with an air lock.

[sandmanxy]

Originally Posted by Muscadine

The presence of air is a necessary part in the primary fermentation stage. Once the SG drops to 1.02+/- then the must is racked to a corboy (secondary fermentation stage) and fitted with an air lock.

thanks,I thought so

[Wine Maker]

Muscadine, you referenced 1.02 in your post. The SG chart I have shows a SG at 1.02 is the equivalent of between 5 and 6 on the brix scale, which would mean the wine still has a way to go in the primary fermentation. 1.002 would put the wine at nearly drt fermentation. I usually ferment to -1 or -2 on brix which would be below 1.000 for complete dryness.

[jagmanvdp]

I am no expert, but from what I have read, the presence of oxygen allows the yeast to form lipds as they reproduce in an aerobic fashion. These lipids protect the yeast from the alcohol that forms during the fermentation process allowing them to live in the higher alcohol environements near the end of fermentation. Without the lipids, they are susceptible to the alcohol and it kills them off at lower concentrations. So, an aerobic fermentation period is necessary for the health of the yeast.

That being said, I have also read that, as fermentation continues, the yeast create a small microclimate around themsleves , once established, and switch to anaerobic fermentation on their own, even if the must is exposed to oxygen. The anaerobic fermentation takes place and produces the desired alcohols and esters, even if you haven't switched them to a carboy with airlock at a specific time. The timing of the switch to anaerobic environemnts is not as critical as some might have you believe, as the yeast tend to take care of that, on a micro scale, by themselves.

That being said, I would switch it over once the SG gets to 1.02 or 1.0 to protect the wine that has formed. Once formed, you don't want that wine seeing a bunch of oxygen...

Just what I have read in winewaking magazine..not an expert on this...

Darren

[Sacalait]

Originally Posted by Wine Maker

Muscadine, you referenced 1.02 in your post. The SG chart I have shows a SG at 1.02 is the equivalent of between 5 and 6 on the brix scale, which would mean the wine still has a way to go in the primary fermentation. 1.002 would put the wine at nearly drt fermentation. I usually ferment to -1 or -2 on brix which would be below 1.000 for complete dryness.

Wine Maker, an SG of 1.020 is where I transfer to a carboy. Agreed, the wine still has a ways to go to dryness but I prefer it to do so in the presence of CO2 not air.

[sandmanxy]

Thanks,that is just what I needed to know

[lv2mkwn]

I usually do my primary in a bucket with a heavy towel over the top secured by a rubber band. This allows for plenty of oxygen and keeps the nasties out. I never use the lid with an airlock...I just think enough air doesn't get to the yeast that way. So far made plenty of wine and had no problems with this method...but I guess you need to see what works for you

[Wine Maker]

I simply place the lid loosely on the pail without an airlock. When the primary is done I transfer the wine to a carboy and then put on an airlock.

[Wine4Me]

{ I simply place the lid loosely on the pail }
when starting my wine kits I close my "wine bucket" tightly by LIGHTY hammering the top down to a tight fit.. That is wrong??