Pambianchi study on degassing

[ShepherdQ]

Hi all,

I stumbled across a study Daniel Pambianchi did of three degassing tools, and I thought I'd share it. I searched, but didn't see this posted anywhere yet.

http://www.techniquesinhomewinemaki...ent and Its Impact on Wine Chemistry v0.2.pdf

Check out Figure 1 on Page 3. After 15 minutes a rod has removed about half the CO2, while a vacuum pump basically never gets that much out (after an hour in the test). Conversely, after the same period of time a rod has injected 3mg/L of O2, while a vacuum pump actually started removing it after 45 minutes. Considering

I would suggest that 15 minutes is that absolute maximum you'd want to degass with a rod, because of the problems of SO2 removal and O2 injection, and that a vacuum pump maybe isn't the best tool for amateurs because of the time required for it to work properly.

Just stirring the pot...

 

[cpfan]

Rob:

Thank you for finding this article and pointing it out to us.

I'm too tired to read the article closely right now, and probably not interested in vacuum degassing enough to read it closely later.

However, I was surprised that the testing was done at 13C (55F). Conventional wisdom is that the cool liquid holds CO2 more strongly than a warmer liquid. Most of us recommend degassing around 23C (74F).

Very few home wine makers will be able to hold the wine at 13C.

Steve

 

[ShepherdQ]

Good catch Steve, I noticed that as well but couldn't find any justification for the lower temp. I can't even reach that under normal circumstances in my wine room, but maybe this is the temp of Pambianchi's cellar?

 

[TonyP]

Good reading during a hurricane.

Most of it made sense to me. I think the study has one substantial flaw in that the rpm rate for the drill / paddle was not measured. Anyone who's used a drill to degas knows rate of spin and change in direction substantially impacts degassing and air intake.

I'd like to see a study on drill / paddle degas rates at different rpms.

Tony P.

 

[MonkeyK]

There is also the hybrid approach of vacuum degassing while swirling the carboy.
I have found that when a straight vacuum stops pulling any bubbles, swirling the carboy will result in enough fizz to fear an overflow.

 

[BobF]

I wouldn't go with time as the determining factor. IME, each wine is different in how easy it is to get the CO2 out.

 

[MonkeyK]

Reading the study more carefully, I see that the author notes that vacuum degassing requires "gently rocking" the carboy. I find that the extent to which this is done affects how much gas evolves.

Two more thoughts:
-Why would he expect anything different from the Gas Getter than from a common vacuum?
-a DIY stir plate might work better than rocking/swirling.

 

[ShepherdQ]

He also mentions using a 'nucleation' device to speed up degassing, (had to look that up), but it sounds interesting. He mentions using screws; has anyone tried this? I would be a little worried about metal screws in a glass carboy, plastic would work just as well I imagine, except they might float and get bashed around by the rod.

 

[wyntheef]

I wouldn't go with time as the determining factor. IME, each wine is different in how easy it is to get the CO2 out.

this is my experience too.

personally, i just don't like the drill attachment because it foams and you have to wait, it foams and you have to wait. but then again, i despise the chore of degassing no matter how i do it. when i grow up and have a real wine cellar, i will hire a high school kid to degas for minimum wage.

 

[ibglowin]

Interesting article but I like many others are wondering what he was thinking trying to degas anything at 55F!!!!!!!!!!!!!!

I fully respect the author and own his book but this just seems crazy.....

We say on this site almost daily to anyone having problems degassing.........

Warm it UP!

I use a vacuum pump (on kit wines only) and do a little back and forth sloshing when needed. 5-10 minutes at 70 degrees.

Stick a fork in it!

 

[robie]

He also mentions using a 'nucleation' device to speed up degassing, (had to look that up), but it sounds interesting. He mentions using screws; has anyone tried this? I would be a little worried about metal screws in a glass carboy, plastic would work just as well I imagine, except they might float and get bashed around by the rod.

In Wine Makers Magazine, Tim V. did an experiment where he sanitized a bottle brush and put it down inside the carboy while degassing with a vacuum pump. In the photo, it was amazing to see how well it worked for nucleating (if that's the right word) and releasing the CO2. Many, many bobbles where streaming off the edges of the bottle brush.

When I use my vacuum pump to degas, it does seem to work much better when the carboy is shaken while degassing is going on.

 

[ibglowin]

Glass beads or marbles would probably work well.

 

[BobF]

I've tried glass and bits of stainless. Notta'.

Etched glass might work. I keep trying everything I can think of.

 

[Dugger]

I usually vacuum rack rather than straight vacuuming the carboy and this seems to get rid of most of the gas ... and I make sure it's warm warm I do this.
There's absolutely no doubt in my mind that using the vacuum pump is far superior to stirring, even drill stirring. I should mention that I mostly do kits.

 

[robie]

I wonder if the author didn't do the degas at such a low temperature, just as a control to prevent anything else from influencing the outcome. I don't think in real life one could get all the CO2 out at that low of a temperature.

 

[ibglowin]

Here is an easy experiment.

Open a can of pop, drink half, set it on the counter and leave it over night. Check it the next morning as taste for carbonation (CO2).

Repeat the experiment only this time place the can of pop in the fridge overnight.

Guess which can still has CO2?

 

[BobF]

But Mike, what if I don't drink 'pop'?

 

[Jarocal]

But Mike, what if I don't drink 'pop'?

Then rack two glasses of wine before degassing and put one in the fridge.

 

[BobF]

But then I'd have to top up with pop!

 

[ibglowin]

That should work!