Spunding in a unitank -- and then dumping trub?

[slidingmike]

Does anyone dump trub after spunding up to pressure in the unitank?

Since we start spunding before fermentation has completed (and since I like to do a 2nd dry hop after fermentation & soft crashing to 58F), I'd really love to be able to do another trub dump before racking to my keg. But I haven't figured out a way to safely dump the trub after fermentation has completed when I've built up pressure from spunding. Does anyone do this? If so, what is your solution?

Thanks for any pointers!

Cheers,
Mike

 

[Rob2010SS]

So, I don't spund. I let fermentation finish and then hook up a carb stone while crashing in my unitank. I do a couple of dumps during that time.

My process is...
1. Move CO2 over to blow off cane.
2. Maintain the same pressure on the CO2 tank as in the tank.
3. Attach a 1.5" TC x 1/2" 90 deg fitting on the dump port.
4. Put a bucket under the dump port, open the valve and perform the dump.

It's quite smooth actually. Identical to what this guy is doing...

 

[Rob2010SS]

He doesn't have CO2 hooked up but I can tell you from just recently doing dump on my Marzen that's lagering right now, it went smooth as can be.

I'm assuming you're concerned about the pressure and it spraying everywhere?

 

[slidingmike]

Yes, when I spund I end up at a pretty decent pressure (depending on style & temperature, from .8 to 1.4 Bar). If I opened up the dump valve at that pressure, there would be an explosive dump -- and probably a lot of beer lost.

 

[Rob2010SS]

Not if you do it like I told you. I routinely dump at 12psi or so and using that 90 degree piece to point it down works perfectly. Just don't open the valve all the way. Just slowly crack it open until it flows.

 

[slidingmike]

I'd tried using a 3' section of silicon hose that I bent & kinked, but still had a blowout. I am a bit hesitant in accepting that a 90 degree bend will somehow reduce 15psi to an easy flow. But I'll give it a shot!

 

[Rob2010SS]

I'd tried using a 3' section of silicon hose that I bent & kinked, but still had a blowout. I am a bit hesitant in accepting that a 90 degree bend will somehow reduce 15psi to an easy flow. But I'll give it a shot!

I hear ya. You don't need to take my word for it. We'll see what others do.

I do think the catch for me is having the vessel that's catching the dump having fairly high walls - like a flask or a 6"tall bucket.

Like I said, don't take my work for it. We'll see what others say

 

[slidingmike]

Rob, no, I really appreciate your suggestions and will give it a shot!

(The tubing I'd used was probably too wide, and my vessel was too shallow.)

 

[Vale71]

I do it routinely as fermentation is usually so fast that there is little trub to dump before it's over. Just get a 1/4" barb to atttach to the dump port and slip at least 6-8 feet of 1/4" hose on it and this will slow down the flow enough so that it won't spray everywhere. To be on the safe side I still coil the tubing inside the largest bucket I can find.

 

[FswBG]

A couple feet of tubing helps for sure. Also, crack the valve just enough to get it moving. There's no need to open it all the way with that much pressure it will blow through the trub/yeast cake and you'll have to wait for everything to re-settle.

Another option is to release some of the pressure from the PRV before dumping trub, then add CO2 once finished back to your preferred psi.

 

[Vale71]

Another option is to release some of the pressure from the PRV before dumping trub, then add CO2 once finished back to your preferred psi.

This is not advisable as it can cause CO2 to bubble from the bottom and that will definitely stir up the trub. Also there's really no need as long as you provide plenty of restriction on the output.

 

[FswBG]

This is not advisable as it can cause CO2 to bubble from the bottom and that will definitely stir up the trub. Also there's really no need as long as you provide plenty of restriction on the output.

Good to know... I didn't realize that would stir things up.

 

[Jtvann]

Believe Rob on the 90 degree bend. It makes a huge difference. So huge that I don’t use it anymore because of how well it worked. It adds a safety net. When you have a few batches in, you might not need the safety net.


I go straight from the unitank into a half inch barb connection. When dumping, I don’t use any hose. Just straight down into a gallon bucket. The key is to go slow. If you want to paint a shadow of yourself on the wall behind you in hops and trub, just open her up all the way.

 

[eric19312]

I use a 1/2 inch TC barb and 2' section of silicone tubing. I start out squeezing the tubing while opening the valve a little at a time aiming for flow like toothpaste into a growler. I really aim for a slow dump in order to keep the full yeast cone moving and not blowing through the cone. I find a sight glass helps, I stop as soon as a see any beer starting to mix with the trub in the sight glass and let things settle again. I don't bother with hooking up gas to the top of the tank unless I am under 5 PSI in the headspace before dumping. If headspace PSI is kind of low after the dump I will top it up then.

I come back and look at the sight glass after a few hours and may repeat the process if the sight glass is still full of trub.

 

[slidingmike]

Thank you, all -- I'll give it a go. I think my first time I ended up getting a pretty bad blockage, and had to open the butterfly valve too much to clear it. I didn't quite paint a shadow of myself on the wall behind me, but it was not pretty!

 

[FswBG]

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