Degassing 135 Gallons

Try a vacuum pump. You can buy a small diagphram pump at a hardware store, and hook up a line to the feremented batch. Many on-premise wineries do it to avoid having to wait sever weeks for the wine to go flat. If you subscribe to WineMaker magazine, check out, Pump Up Your Winemaking (Feb,

2004). There's an article in there that describes how to degas your wine, etc.

NOTE: make sure your wine had been filtered, or fined, or is free of sediment before dagassing with a vacuum pump. You'll end up with a cloudy mess that'll stay in there for weeks or months.

Even so, other than letting it go still on its own for a year or two, that's your alternative.

Jeff

Careful! On a thinwall tank you may well collapse the sidewall. They're designed to resist outward pressure, not inward. Think of the strength of a 2 liter soda bottle against bursting vs. how easy it is to deform it with your fingers. No experience to go by, just some basic engineering.

Hi Paul, I have never heard the term "degassing" used in a commercial winery (in this context). Wineries use pumps to rack from tank to tank. Pumps produce a negative pressure on the suction line, and the negative pressure automatically removes dissolved carbon dioxide from the wine. You probably will use a pump to handle 135 gallon lots, so you may not have a "degassing" problem. Good luck, Lum Del Mar, California, USA

135 gallons is a lot of weight already on the inside wall, pushing outwards. We're naturally assuming that the wall is thick enough to withstand the pressure of that weight from within. Therefore, we're also assuming the amount of low pressure on the upper air surface (created by the gentle pump) is minimal (just enough to draw trapped gasses to the surface and suck them out: it only takes a -1 lb/sq in. less than ambient over a period of several hours to do the trick), while the actual weight of 135 gallons of fluid keeps the outward pressure on the wall to prevent collapse (implosion).

Even so, Lum's posting below probably has a point if you're already using a transfer pump. If you're racking or transferring with gravity (as some wineries do), then a pump may still be an alternative option, in the way Lum mentioned.

Whatever pump you choose, it will be a good idea to research the physics of it all (and maybe experiment with a tank of water first).

Jeff

If you barrel age the wine, that problem will disappear. BTW, I wouldn't even _think_ of applying vacuum to a tank. It'd collapse for sure.

Tom S

I've seen collapsed tanks in wineries where the winemaker forgot to open the tank before pumping out of it. I wouldn't try to de-gas that way.

In some instances I have had to de-gas large volumes of wine, in particular rieslings which were not fermented completely dry, and so were kept at 35F or so from the time they reached the residual sugar I wanted, normally in October or November until February or March when I bottled them. If the wines have too much residual CO2, they're really hard to bottle, so the way we de-gassed them was to open the top of the tank, run a hose from the bottom valve to the pump (with a rubber impeller moving the wine), and then another hose in the top of the tank and back into the wine. We'd then pump the wine until the impeller no longer drove CO2 out of solution.

Dave

**************************************************************************** Dave Breeden snipped-for-privacy@lightlink.com

I stand corrected.

Degassing from large stainless steel must be different from degassing from small glass. We used to degass between 2 and 10 carboys at a time, on a single pump over an 8 hour period to completely flatten the wine. In the four years I worked at this place there was never even a hint of implosion. I'm not there now, but they're still doing it that way with a 100 percent success rate.

I'm not a physisist, and those with experience with higher volumes in steel must be the wiser.

Personally, I've always been in favor of time and bulk ageing (as already mentioned), in oak, or whatever. It's gentler on the wine anyways.

Even so, if you bottle with a simple enolmatic bottler which works on a vacuum principle to draw the wine from the carboy, there is a certain level of degassing taking place even as your bottle is being filled. But if the wine is terribly gassy at bottling time, I don't think the Enolmatic will do a thorough job.

In the long run, probably the best way to degas wine is the way everyone's been doing it for hundreds of years. Just let it sit there for months and drink beer while you'r waiting.

Jeff

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snipped-for-privacy@lightlink.com

No, but I use my Enolmatic for degassing by bypassing the bottling arm and using the pump to evacuate the headspace. A half hour seems plenty to remove a substantial portion of dissolved CO2, even in a cold fermented white.

Brian

I'm not acutally sure that degassing in the way that you suggest, by sucking on the headspace above the wine, would implode a tank. It might be okay. What DOES implode atank is leaving the top vents all sealed, and starting to suck wine from the bottom of the tank. Someone with more knowledge of the physical world than I can probably explain it better, but pulling all that liquid out creates a tremendous vacumm, more than, I think, you could create by just sucking on the headspace.

Bad to find out the hard way, though.

-- Dave

**************************************************************************** Dave Breeden snipped-for-privacy@lightlink.com

Brian,

Could you describe in more detail how you do this? I have an Enolmatic and love bottling with it, and have struggled with my last two batches of white wine that I cold fermented to get them to degas adequately - it would be great to use my Enolmatic to do it.

Thanks,

Ed

i would assume then, that you simply run a longer tube from the resevoir to the bung (bypassing the arm, as you say)?, or do you run a tube directly from the pump intake?

(I'm guessing you still use the resevoir as a buffer, right?)

Jeff

We do however correct CO2 levels, and the usual way to reduce them is to sparge with a low volume of nitrogen. This does cause some flavour stripping (but I'd think that a vacuum does worse).

Cheers,

Andrew

Andrew, Thank you for the post. I do testing for several small, local wineries. By the time a wine has been racked two or three times and filtered once or twice, the CO2 content is low and it is seldom an issue. Are you using CO2 in the headspace? Some wineries like spritzy white wines. Are you deliberately maintaining high CO2 levels and then adjusting down to near the tax limit at bottling time? Regards, Lum Del Mar, California, USA

Yes, we're maintaining CO2 gas cover on our tanks. I'd like to use argon, but it's too expensive. I am more concerned about oxygen pickup than high CO2 levels, therefore I use the nitrogen method to reduce CO2 prior to bottling.

Not tax limits, as they don't apply to us in Oz. Instead we have high levels because of gas cover, and reduce to get the right taste.

maintaining

Thanks for the reply Andrew. I appreciate the information.

I don't use the reservoir, I just hook up the pump intake directly.

The carboy has a 3 piece airlock (without the "dancing hat") with some tubing running off the central stem. This interfaces to the smaller diameter hose that comes off the pump intake that normally connects to the reservoir. You have to work out a coupler for that, I have a klugy setup that would not set a good example. ;-)

I give myself lots of headspace because the gas will cause a lot of foaming. This usually involves drawing off a pint or so and keeping that in reserve until the degassing is over. I also have an anti-foam compound that helps. Start the vacuum setting low, there will be a lot of gas coming off in the initial stages. As it winds down, you can turn the vacuum up.

Towards the end, I feel safe leaving it unattended, but not at the start.

Brian

Thanks Brian - I'll have to give that a try.

Ed

I bet youdda had fun working for Capone back in the 20's. I can just picture that.