Can you rack too often in a closed system?

[Trauts]

I recently purchased some kegs to use as primary/secondary fermenters.

Recipe calls for removing the fruit bag after a couple of days (even when primary isn't done!). Doing so would expose everything to oxygen, so I'd like to avoid that if possible. (Is that paranoid?)

Instead of removing the bag, could I just rack from one keg to another with CO2, then pull the bag out of the empty keg? Or will racking during active fermentation (racking without oxygen exposure, specifically) impact the wine negatively? I haven't bent the liquid tubes, so I could deliberately transfer the sediment, too, if that matters. I've found plenty of posts saying not to do this in non-keg context, but none of them are talking about racking when no oxygen is being introduced.

As part of this idea, I built an airlock that attaches to the gas-in post. This seems like a good way to further reduce chance of oxidation since it can be removed quickly without fumbling with the rubber seal.

Thanks!

 

[bernardsmith]

Hi Trauts. My immediate response is that wine ain't beer and most wine makers who ferment fruit (think grapes for example) have no problem fermenting in open vats , stirring the fruit to ensure that the cap that forms is kept constantly wet and that all surfaces are in contact with the yeast. While oxidation is a potential issue the amount of CO2 being produced during the active stage of fermentation and the yeast's ready uptake of any O2 introduced into the must really removes such concerns from wine makers. That and the low pH that is typically associated with fruit wines (not only grapes) preventing any concern of bacterial infection means that home wine makers are far more relaxed about fermenting in buckets loosely covered with towels or dishcloths than you appear to be... Bottom line: wine makers tend to adopt a more organic approach to fermentation than the engineering approach that brewers seem to prefer.

 

[DoctorCAD]

How do you know that your grape bag has even been anywhere except drying out on top of your wine?

I can honestly say this is the first I have ever heard of a closed ferment...of anything.

 

[Trauts]

The fermentation itself isn't closed, but once it stops bubbling, you can transfer to secondary (or do future racking) with a guarantee of no oxygen exposure. Clarified my original post because I did say 'closed system' and that was kinda ambiguous

it's a peach wine, but I doubt that makes any difference. I guess there's not a way to know whether the fruit bag been drying out on top (without opening it anyway, and if I was going to do that, then there's no point to the rest), but is drying out fruit typically a significant problem with winemaking? I would have assumed that sitting in a liquid it would keep it wet from soaking in there. (In the future I suppose I could weigh the bag down)

I've always used carboys before, but it was such a PITA I got tired of it. (Carboys actually led to me leaving homebrewing for ~3 years because I hated the siphoning so much.)

there's some reading on using kegs to ferment if you're interested in getting in on it. There's also this, which seems to be a fully closed system, but that seems like an excessive solution by any measure.

Really, more than the oxygen aspect, I don't want to stick my hand/wrist inside the keg to pull out the bag, since that could introduce bacteria, etc. There's no reasonable way to pull the bag out without getting your arm a fair ways into the keg, unless you have some sort of grabber-claw thing.

 

[Trauts]

it does sound like you can rack wine earlier than I thought. This link at least suggests racking after 5-7 days.

In previous (carboy) batches, I probably would have waited 2-3 weeks (or until bubbling had really slowed down) before racking, but I'm new to wines with actual fruit (vs stuff like ginger wine where the flavor is from boiling a root or just fermenting juice from a bottle)

It sounds like if racking after 5-7 days is the norm, it's sorta a moot point whether or not it benefits from reducing oxygen exposure.

 

[bernardsmith]

So two things can happen if you are fermenting fruit. The first is that the top surface of the fruit forms a cap and that cap remains relatively damp - not wet and not dry and so a perfect host for bacterial and fungal spoilage (think fur and fuzz on berries) and that spoilage can then ruin your wine.
The second thing that can happen is that that cap can become a mass solid enough to hold back all the CO2 being produced beneath it. Half the weight (let me repeat that , half the weight ) of the sugar is converted to CO2. That is a lot of CO2. And all that CO2 trapped beneath a cap of fruit can build up an ENORMOUS (I will repeat that : an ENORMOUS ) amount of pressure. I will let your imagination run with (or from ) that idea... but if you are running from it you best be very quick on your feet.... if yer knows what I mean...