What is the purpose of "Capping" fermentation

[killroy]

I did a search on this forum, but could only find that capping saves CO2. There is the notion that capping helps speed conditioning where I work.

We did a new yeast prop and it is ripping well below our "cap" gravities. PRV's have gone off as a result in some cases. e.g. 1.015 down to 1.011 after capping.

I did the Micro course at Siebel in Montreal recently. Lalamand has a product under development to create nucleation sites to get CO2 out of solution during fermentation. Seems that yeast dont' like the pressure? Capping would cause yeast to start floculating due to increased CO2 pressure?

Thanks

Rory

[South County]

Capping aka "spunding" is a pretty common practice to gain about one volume of co2 (more so with lager production). Up until modern carb stone systems spunding was how it was done, as well as bottle conditioning. I don't really think this speeds "conditioning" other than you have a stronger co2 solubility. Sounds like your possibly spunding too early (to much fermentables left). Providing you have fermented the bulk of your sugars (95+ %), the PRV shouldn't be popping, I don't recommend spunding with terminal PRV valves (foil type). Also the yeast is already preparing for a hostile environment and at that point should begin floc out. While it is true yeast tend to stress under high pressure this is more related to tank height in some cases, or capping to early in your case. I don't know what your recipe calls for but if your trying to retain sweetness you may choose to make a mash adjustment.

[Ted Briggs]

if you want to spund early to capture some co2 for a natural carbonation i strongly suggest using a spunding device. They can be set for the desired preassure and will release exess co2. prv's shouldnt be used in this way, they are an emergency device.
On the other hand, I belive in getting rid of all gas from primary fermentation, letting all those So/so2 gasses to wander out of the beer. Idealy for natural cabonation I would use a karusening technique and prefferably in a secondary tank. No matter how often you pull yeast some will remain and you have the chance for autolysis flavors with extended conditioning.

[wiredgourmet]

I belive in getting rid of all gas from primary fermentation, letting all those So/so2 gasses to wander out of the beer.

You mean, insofar as one reasonably can, right? I can't think of any way to make beer truly flat without damaging it, either with temperature or agitation.

I personally don't see a volume or so of CO2 from primary fermentation as a toxic substance, but that's just me.

[gitchegumee]

Agree with Ted on the spunding devices. Don't exercise your PRV's. I Don't let my beer go "flat", though. I put the spunding device on as soon as we're about 1P from terminal gravity. Sulfur compounds aren't much of an issue for me, but still, what's the difference between the last 1P of fermentables and fresh krausen? Why would sulfur compounds be present in one fermentation and not the other?

[killroy]

Thanks for the replys.

I have experienced the increase in sulfur due to a blowoff being shut during the ferment.

What about the re-uptake of diacetyl? This is hindered by increased pressure correct?

That being said, our house yeast is attenuating further than it used to so I guess mashing higher/thicker or changing our FGs/CAP gravities is in order.

[Ted Briggs]

[QUOTE=wiredgourmet]You mean, insofar as one reasonably can, right? I can't think of any way to make beer truly flat without damaging it, either with temperature or agitation.[QUOTE]

Correct- I wasent suggesting a co2 scrub, just waiting to final attenuation before spunding.

[MaltAlchemist]

I am planning on spunding, and from what I understand, you set your spunding device to a certain pressure and once your tank reaches that pressure, it blows off the excess. I know about CO2 toxicity, but wouldnt excess CO2/SO2 just blow off. Bottle conditioning/ carbonating is under pressure without the luxury of a blow off, so whats different in the aspect that you should let your gravity drop to 1 above terminal before capping/ spunding? Cant you spund earlier because you still have blowoff?

[Jephro]

I have always thought Co2 Toxicity was a bunch of BS, i have had other brewers concerned that i harvest yeast from a tank under pressure.

I had the opportunity to speak with Chris White at the Hopunion Hop & Brew School this year and asked him about this topic. To sum up his answer, assuming you are capping, bunging, spunding whatever you call it at the end of primary, up to 15 PSI (1 Bar) should not have any detrimental effects on yeast. Pressures over 20 PSI could cause problems with yeast.... or your tank for that matter

so whats different in the aspect that you should let your gravity drop to 1 above terminal before capping/ spunding? Cant you spund earlier because you still have blowoff?

I usually attach my barby-kuhner (set to 15 PSI or 1 Bar) the third day of fermentation when i still have slight blowoff activity, 2-4°P > terminal. With my Hefe, if i still smell any sulfur i wait to cap, or don't at all to let it blow off otherwise i end up scrubbing by means of a violent x-fer to the BBT which releases all of the Co2 anyway.

-a side note, it is difficult to acheive full carbonation by this process in ales because when you crash the tank more Co2 goes into solution and 15 PSI @ ferment temp turns into +/- 7-10 PSI @ conditioning temp. The amount of head space in the FV obvioulsy plays a role in this but i usually get my ales about halfway carb'd. Lagers on the other hand you may be able to get 80-90% carb'd - but watch out for sulfur...

-jeff

[killroy]

Thanks for the replys.

A very prominent West coast brewer told one of my co-workers at a recent event that the increased pressure created by capping would help take up diacetyl at the end of fermentation.

Cryptic enough?

Somebody has to have something about capping other than saving money on CO2. There just has to be more. Right?

Killroy

[SRB]

....Somebody has to have something about capping other than saving money on CO2. There just has to be more. Right?
Killroy

Anthropogenic climate change? Thats all I got.

[gitchegumee]

Many people (myself included) think that spunding produces a finer carbonation, and better lacing versus force carbonation.

[Jephro]

Many people (myself included) think that spunding produces a finer carbonation, and better lacing versus force carbonation.

-what he said!

[liammckenna]

I'm with Gitch and Jephro.

Basically, foam happens once in beer. Beer can make a lot of foam, but not an endless amount. I want that foam in my customers glassware as much as possible. By spunding, you create a finer bead of carbonation and also, you'll need to create less foam in you beer while you process it. I have encountered a few, but not many, supplemental carbonation systems for beer that create no foam at all. All have involved quite high pressures.

You can achieve the same fine bead by carbonating brite beer via extensive head pressure alone in a cold tank with occasional gentle agitation/circulation. It also takes time and very cold temperatures. Not practical for many of us.

I've seen fermentation systems (some in very large breweries) which always maintain slight positive pressure in the fermentors (2-3 PSI), regardless of the stage of fermentation. The explanation given to me was that it helped to control foam formation in the fermentor. Apparently there was no measurable detrimental effect on the resultant beers. I'm sure that's debatable.

We cap our own beers (set spunding apparatus to 15 PSI) anywhere between 1-2oPlato above terminal gravity. We've had no issue with those of our beers which need a diacetyl rest using this method. Diacetyl uptake, for us anyway, does not seem to be a problem under these conditions.

I should point out that I do tend to let the fermentation 'run' in these last few degrees of plato towards end fermentation. In other words, if my set point for fermentation of a particular beer is 68oF, once I cap the fermentation, I will adjust the setpoint to a ridiculously high number so the cooling will not kick on and shock the yeast at a sensitive stage where nutrients are rapidly depleting.

Pax.

Liam

[Jephro]

By spunding, you create a finer bead of carbonation and also, you'll need to create less foam in you beer while you process it.

I will occasionally, usually on slow filtrations, attach the spunding device to the receiving BBT tank during filtration to and keep a few PSI differential to prevent foaming during process.

If you have a good sight glass you will see bubbles rising in it if you are foaming the beer in the BBT due to too low a pressure in the receiving tank. In which case you are loosing, at least some of, the benefits of spunding.