Falling Film Degassing

[Grasshopper]

From my previous life as an engineer I know that a falling thin film of liquid is very efficient for mass transfer (i.e. moving a material to/from the liquid phase to the gas phase it is falling through). It is efficient because the transferring material (CO2 in our case) doesn't have far to go within the liquid to reach the surface and the turbulence of the film continually renews the surface with fresh CO2 containing wine. Thus I devised the following method of vacuum racking that should be more efficient than simple splash racking to move CO2 from the wine into the reduced pressure gas phase in the carboy. The method should work for gravity racking but probably not as well.

I took the racking cane which has a short leg at the top bent 90 degrees from the longer leg and inserted this into the stopper so that the transfer tube connects to the long leg and the short leg is in the carboy pointed at the side. Pulling a vacuum on the carboy causes the wine to impinge on the side of the carboy and fall down the side. See pics in the file below.

I have tried this a couple of times now and it seems to do a much better job of degassing compared with just having the wine fall straight to the bottom in a single stream. I wonder if anyone else has tried this and/or knows of a reason why it may not be as good of an idea as it seems.

 

[vacuumpumpman]

Grasshopper
I like your idea - alot!
In the past I have tried and liked using wort aerator - it would spray a fine mist,causing the CO2 to be driven out even quicker. Your set-up is much simplier

Please keep in touch as your progress with your new design !!

 

[pjd]

Great Idea Grasshopper! Absolutely correct in theory. Thanks for posting this.

 

[dralarms]

That's a great idea. Why not cut the cane down some? I bought one and cut it down so its not sticking up so high.

 

[DoctorCAD]

I do that at every racking. I know I have enough k-mets in my wine to keep it from oxidizing, so I figured it wouldnt hurt.

 

[Putterrr]

I also use this method although my bent part is shorter so the wine goes along the top of the carboy and then down the side. I find it makes less foam in the wine as long as I keep the vac gauge below 10. The total length of my bent cane is about 7 inches.

cheers

 

[JerryF]

I also use this method although my bent part is shorter so the wine goes along the top of the carboy and then down the side. I find it makes less foam in the wine as long as I keep the vac gauge below 10. The total length of my bent cane is about 7 inches.

cheers

Being a former chemical/environment engineer myself, immediately on seeing this post from grasshopper, it struck me as so obvious! This is basically what's behind the way we used to design and operate industrial water cooling towers (to drive off entrained heat). Way to go grasshopper!

 

[jswordy]

GENIUS!

 

[vacuumpumpman]

I had time to go on the computer and find a link to a wort aerator - it literally pushes on the bottom of the racking tube. I still like the idea oh heating up the racking cane after it has been pushed thru the bung and have it splash against the carboy wall.

here is the link to the wort aerator
http://morebeer.com/view_product/15779/102214/Siphon_Spray_Wort_Aerator

 

[btom2004]

Looks like a great idea, I will give it a try.

 

[Grasshopper]

It is good to see that at least a few others have used this technique without reporting problems. I am now going to take dralarms advice and cut down the length of the long arm to make this more manageable. I didn't want to ruin my $1.59 racking cane until I was sure I was going to continue this way (and people say engineers are cheap!).

 

[dralarms]

That's funny, the first thing I did was cut one down so it wasn't sitting 3 foot in the air. I just hope its not cut down so far that I can't use it they way you suggested. If not I'll hack another one.

 

[Chiumanfu]

Sorry for bumping a necro thread but I just had the opportunity to try this today and it worked better than expected. After vacuum racking with the falling film method, I put the carboy under vacuum as I normally do to degas and... nothing. Which kind of sucks because I was all setup to take a video of vacuum degassing for one of my articles. So here I am...camera rolling...nada...nothing...not enough bubbles to count on two hands. I'm going to try it on a couple more batches to confirm it is consistent and repeatable, but for now this looks like my new standard degassing procedure. Thanks Grasshopper!

 

[vacuumpumpman]

I would like to thank Grasshopper for coming up with this great gadget that saves even more time in the process of removal of CO2. It still uses the 6.5 bung ,so you will not have to switch racking canes in order to use this complete setup. I am now selling them for 12 dollars with purchase of pump or 14 dollars individually (includes shipping). Please Pm me with your email address and I will put a PayPal money request to you, until I can get my shopping cart up and running properly.
They are flexible and are only 9'' tall to provide more stability.

 

[dralarms]

Nice. I may have to get one.

 

[Stressbaby]

I'm in for one.

 

[geek]

I would like to thank Grasshopper for coming up with this great gadget that saves even more time in the process of removal of CO2. It still uses the 6.5 bung ,so you will not have to switch racking canes in order to use this complete setup. I am now selling them for 12 dollars with purchase of pump or 14 dollars individually (includes shipping). Please Pm me with your email address and I will put a PayPal money request to you, until I can get my shopping cart up and running properly.
They are flexible and are only 9'' tall to provide more stability.

so basically replaces the older style that has the longer tube/cane and that goes straight down, correct?

 

[dralarms]

No, its an additional piece, comes complete with bung and vacuum tube. Its worth every penny.

 

[geek]

what I'm trying to say is that this setup replaces the older one, you both rack and degas with it as well.

 

[FABulousWines]

what I'm trying to say is that this setup replaces the older one, you both rack and degas with it as well.

Yes, that is true.