Vacuum Secondary, and a forced CO2 question

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PerryS

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Dec 19, 2012
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Location
Fort Collins
If you've ever been on a family road trip, there will be a time when you hear "are we there yet?" from the back seat. Every parent dreads that question. Likewise, every brewer must answer the question, "Is it done yet?" For every batch.

In the pursuit of bomb-proof (in the bottle-bomb sense) high-gravity ales, I have fallen into the habit of evacuating the carboy to de-gas the wort. Winemakers, who regularly deal with 1.200+ OGs, will recognize "de-gas". I happened upon the vacuum secondary concept when I was attempting to de-gas a mead. The usual DIY method is to cut a plastic clothes hanger to size, and whip the ever-livin' **** out of the must with a variable-speed drill. Seemed a bit abusive to the yeast, by my reckoning. A slight shake/swirl under vacuum pulls an amazing amount of CO2 out of wort/must.

In high-gravity worts/musts, the yeast reach a point where they can no longer exhale CO2/ethanol because the solution is saturated. The osmotic pressure on their little cell membranes just doesn't allow them to convert any more sugar. As the Queen would say, "this is a situation up with which we shall not put."

I use a #6 cork that has been drilled (1/2" hole saw, IIRC), and has a Vacu-Vin (tm, likely) stopper in it. Vacu-Vin is a hand-operated vacuum pump purportedly for wine snobs, but it makes a dandy [cheap!] method for reducing the osmotic pressure on my overworked high-gravity yeasties. (If you must know, I brew with Wyeast 3787 High Gravity Trappist, and Lavlin D-47.)

The Vacu-Vin allows the yeast to ferment another .001-.002 FG, and then really stop and drop. Then, the must/wort clears phenomenally. I have concluded that cloudy beer is mostly yeast that are riding CO2 bubbles up and down the carboy like a carnival ride. The key is to let the yeast do their thing, exhaling CO2 and ethanol up to their cellular membrane limits for free glucose vs ethanol/lipid degradation. At that point, it's just not possible for them to make bottle bombs, because they are truly "done". The wort/must falls clear when the yeast are done riding the CO2 elevator and dragging every random protein with them.

I do, however, have one question, which is the point of this post.

How do I remove the cork when it's time to bottle? There is a vacuum in there. Fort Collins is at 5000', and the pressure altitude in that carboy is somewhere around 60,000', like close to outer space. When it's time to bottle, should I just let the air back in? Should I blow CO2 back into the carboy? If so, how? Or should I just not worry about it?

I suspect the forced CO2 folks have some kind of cool tool to do this. If you have a cool [cheap!] way to remove the cork without letting in a bunch of O2, I'd like to know! Thanks, and RDWHAH.
 
"Forced CO2 Folks" don't hardly ever deal with vacuums. When we want something to come out, it usually has pressure behind it (sometimes more than we'd like ;) )

If you have some CO2 handy, place a trash bag over your vessel, flood it with CO2, and release the vacuum on your stopper...

Cheers!

[edit] Or don't - and then flush the headspace with CO2. If you don't have any gas handy, you're on your own ;)
 
there is absolutely no need or benefit to de-gassing beer.
you're going to be putting co2 back into the product, not trying to make a product with no dissolved gas.

beer yeast don't need the amount of 02 during fermentation that wine yeasts do so co2 saturation is not an issue.
 
I have a vac system and use it to drastically reduce the lagering time on Pils. I run a mild 7" vacuum to clear the beer in the secondary before kegging. At 7", water in the beer, nor, the alcohol will be boiled off. It works well. The first time that I demonstrated it to a few brewers. I had the same response as some have written in this topic. Until they saw how it worked and what it did for the beer. I have a stainless header that has 2 ports. I hook the pump and CO2 tank to the ports. Both ports are valved. After the beer falls bright. I break the vacuum with CO2 and use the gas to push the beer into the keg. I do the vacuum when the beer is fairly stable. Usually with less than 1% fermentable sugar in solution. Letting the beer get down that far, keeps the foam down in the fermenter, once the pressure is dropped below atmospheric. I have the system for about 12 years and used half kegs as fermenters before going with Blichmann fermenters. On the Blichmann secondary, I had a spunding valve installed in place of the pressure relief. I remove the valve and screw a plug in, before running a vacuum. I hook the header to the tri clover blow off fitting on the dome. If you are going to attempt to use a vac system that doesn't use the venturi type apparatus. You'll need a corny keg receiver to catch the foam before it gets pulled into the pump. You'll be surprized to see how much CO2 is in solution in what appears to be a beer that is done working. I use a brewers vac system, it is a vane pump. It pumps 30 CFMs and is good up to 100 gallons. I found it on Thomas Register under beer filters. IMO, it's a good device for reducing aging time and costs less to operate than a refrigeration system.
 
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