Trub dump air bubble, fact or fiction

[Whisky River]

Is there a consensus on whether dumping trub from a conical allows an air bubble into the fermenter each time you open the valve? It seems like this could potentially introduce quite a bit of oxygen if you were doing multiple dumps throughout fermentation/ dry hopping/ conditioning.

Would reducing the TC valve to a hose outlet help minimize any oxygen ingress by forcing the outgoing trub through a small diameter space making it harder for air bubbles to pass by it and get up into the fermenter?

Does anyone purge their dump valve set-up? Maybe by using a sight glass with a second butterfly valve on the end, or would that just be going too far?

 

[PCABrewing]

Easy enough to test between brews.
Fill it with water and watch from the top when you open the valve.
Same method should allow you to test mitigation attempts.

 

[hotbeer]

Is there a consensus on whether dumping trub from a conical allows an air bubble into the fermenter each time you open the valve?

Surely you jest about the consensus thing.

I just dumped most of the trub yesterday from my small 3 gallon fast ferment. I have a 1.5" butterfly valve below the site glass and a TC reducing section to get it smaller and mor appropriate for the half inch tube attached.

Usually with other brews I was able to push out the trub and yeast without getting a bubble. I have a clamp on the vinyl tube I can pinch it off with just as the last poop plops out. However I did a serious over pitch this time and have a lot of yeast that seems to not want to fall easily through the reducer and narrower tube. So I got a bubble.

It's a IPA that is not dry hopped. I don't expect it to matter since the beer will be gone before oxidation ruins it. If that bubble is even enough to ruin the not quite 2 gallons in there. Besides, for the amount of trub/yeast dumped, the volume of air that will get into the beer from the airlock or other places will be greater. I actually have to remove a stopper in the lid to let air in so the dump can happen.

You actually could just fill a container of water or other sanitary stuff and have that water level just above the exit of your FV to ensure no bubble goes up. But that depends on how you have your trub dumping on your conical. And I've found it to be more hassle for me than necessary.

 

[tdf]

If you can put a little positive pressure on your fermenter with co2 you should be able to avoid it. Otherwise it's pretty much inevitable.

 

[pvpeacock]

I've never seen or heard a bubble when dumping trub/yeast. I don't see why you would get a bubble since the volume dumped is being replaced with air (or CO2) coming in from the top of the conical. It's not like a 5 gallon water cooler bottle where the only way in and out is through the mouth of the bottle which results in the glub, glub of air bubbles.

 

[bailey mountain brewer]

I agree with @pvpeacock .. as long as there is something (co2 pressure ideally) going in the top, you should have nothing to worry about. I use 2ish psi of co2 pressure, under my conical is a sight glass, valve, elbow, tc fitting to hose barb, short hose into a bucket. Crack the valve slowly and watch the sight glass. I've never seen anything move up the sight glass.

 

[Whisky River]

Surely you jest about the consensus thing.

I don’t know what I was thinking!

I guess I will test with water after the current batch is in the keg, but even then I wouldn’t be able to test under pressure with the lid on and see anything, and I’m not sure how much different water would behave from trub/hop slurry. I’m also curious to hear if different valve and reducer configurations might make a difference.

Right now I’m keeping the fermenter under about 2psi and just have a 90 degree elbow to the butterfly then to a hose barb adapter to a short hose into the bucket. I like an opportunity to over complicate things as much as the next guy, so maybe I’ll try adding a sight glass and some more fittings just for fun. Or maybe I should just RDWHH but either way, it’s always good to hear how others are tackling the same issue.

 

[mac_1103]

I’m not sure how much different water would behave from trub/hop slurry

Surely there's a beer geek somewhere who has developed a trub/hop/slurry simulant.

 

[Dland]

Is there a consensus on whether dumping trub from a conical allows an air bubble into the fermenter each time you open the valve? It seems like this could potentially introduce quite a bit of oxygen if you were doing multiple dumps throughout fermentation/ dry hopping/ conditioning.

Would reducing the TC valve to a hose outlet help minimize any oxygen ingress by forcing the outgoing trub through a small diameter space making it harder for air bubbles to pass by it and get up into the fermenter?

Does anyone purge their dump valve set-up? Maybe by using a sight glass with a second butterfly valve on the end, or would that just be going too far?

Yes, one probably will introduce some O2, how much probably depends on ones rig.

But it is something you do not need to worry about if you have a C02 tank and regulator.

When I do a trub dump from fermentor, I just hook C02 tank with regulator set at 2 or 3 PSI to tube on top of fermentor for blow off tube, same thing as when I'm racking kegs. That way, the wort or beer that leaves the fermentor is displaced by CO2, and beer flavor is saved.

If you are using one of those little plastic air locks at top of fermentor, replace with a tube going down to container filled w liquid. I use a Starsan solution. Hook tube to CO2 tank when displacing beer from fermentor.

 

[hotbeer]

Right now I’m keeping the fermenter under about 2psi and just have a 90 degree elbow to the butterfly then to a hose barb adapter to a short hose into the bucket.

Oh, you have a pressure capable conical. That seems like it'd make things easier to keep air out since the pressure will push the trub/yeast out. If your valve is a huge valve and the line coming from it just as big, I'd think a reducer will definitely be needed. Otherwise it'll be easy for the beer to push through the slower moving trub and out the exit.

And no concern for air having to be let in the top of the FV as long as there is enough pressure and headspace to give that extra volume of CO2. But if your pressure goes to zero before the trub is out, you'll have to let some air or something in at the top.

If you are using a vinyl or silicone tube on the end, just be ready to pinch it off with a clamp so that it doesn't empty and air go up to the valve waiting there for bottling day to be let into the beer.

I use a small pair of needle nose vice grips with some rubber vacuum hose for automobiles slid over the jaws to pinch off the end of the tube without damaging it.

 

[beren]

Even glass could hold 1-2psi