Vacuum

[Vlabruz]

I see the use of vacuum to limit o2 exposure. But, when you release the vacuum doesnt 02 rush into the carboy as pressure equalizes? Is it minimal?

 

[winemaker81]

It all depends on your head space. If you have a large headspace, it's a potential problem. You need to maintain the vacuum OR fill the headspace in other ways.

O2 exposure is a normal part of winemaking. For a home winemaker, limit exposure post-fermentation and dose with K-meta to address all contaminants.

 

[mikewatkins727]

Time is a factor here. So I finish a transfer and have 2" or more head space on a 3 gal carboy. By the time I add marbles, water or wine is a matter of minutes or maybe an hour (stretching it.) Two inches of head space over 3 or more months is a concern to me. You add k-meta to chew up the O2 floating around while you go get the marbles. I seriously doubt the wine will be damaged beyond use in a week, maybe two There have been numerous times I think I screwed up the wine only to drink it all a year later. Winemaking can be very forgiving. It's not like slamming the oven door on a cake that is still baking.

 

[Rice_Guy]

There are many ways to use vacuum. You can use vacuum as a transfer agent. or You can use vacuum to manage head space. or You can use vacuum to degas and live ever after with atmosphere levels of oxygen in the head space. or You can pull and keep the vacuum.

That noted my current practice is to run standard air locks for about ten months. At the point where I am prepping for bottling I switch to check valves. ($4 at Grainger) With that in place I will pull a 15 inch Hg > let CO2 fill the ullage > pull a second vacuum and then let it sit. In this I am trying not to spend all the inert gas at once so I can open/ manipulate third and fifth times.

I see the use of vacuum to limit o2 exposure. But, when you release the vacuum doesnt 02 rush into the carboy as pressure equalizes? Is it minimal?

 

[distancerunner]

Rice:

Do the check valves go in a single hole stopper or do you use a double hole and insert a gauge in the second hole?

Please provide a link for the check valves.

 

[Rice_Guy]

Do the check valves go in a single hole stopper or do you use a double hole and insert a gauge in the second hole? , , , Please provide a link for the check valves.

About a year ago we had a discussion about holding vacuum and vacuvin stoppers and check valves
so I killed a few days testing hardware. > results
View attachment 85669
View attachment 71437
View attachment 72145
Conclusions
* An effective vacuum set up needs to have the same seals as one would use with gas lines
* old corks get hard and are not effective at holding a vacuum
* a carboy with wine in it will release CO2 and not hold a vacuum as long as a dry system
(working definition of a good enough degassed wine was the carboy can hold a five inch Hg vacuum for 30 minutes)
* The rate of change decreases as the pressure differential decreases, There was still a slight difference on gage at thirteen months with the empty flask
* A new vacuvin check valve is effective at holding vacuum
* A new plastic check valve is effective at holding vacuum (polysulphone and nylon construction)
* To know how well a hardware setup is performing one needs to have a vacuum gage

i have nylon as well as polysulphone types
https://www.grainger.com/product/GR...-4DHY4?opr=PDPBRDSP&analytics=dsbrItems_4DHY9