new to pumps, left a lot of wort behind in the brew kettle

[ringneck]

Hi all, Started brewing a couple decades ago, but haven't brewed for last few years. Always used Gravity for transfers from BK to fermenter. Never had a problem with getting all of the wort out of my brew kettle through a bazooka screened dip tube previously.

I got a new system which includes pumps, so Monday night I re-entered the brewing game partially using this new set up. I've run into 2 problems I've never had before

Instead of using gravity to empty my brew kettle, I ran the BK output into the pump, and then pumped through a new CFC into my fermenter. Same BK, screen & dip tube as before.
BK valve fully open, pump input valve fully open, pump output valve fully open (made sure it was primed) and I used the CFC output valve to throttle flow so the exit temp was 70*
Worked great until the wort level was down to the BK output valve level. At that point, it stopped transferring wort and it left at least a gallon in the BK, probably more.

Let's pretend for a minute that I had remembered to close the output valve on my fermenter, and didn't dump 1/2 gallon of wort on the floor before noticing. (chalk it up to shaking off the rust from not brewing in a while)

Bottom line, is I only got ~3 gallons in the fermenter. It's a 6.5 gallon anvil fermenter, so there is a ton of headspace. I'm not seeing any blowoff or activity.

so 2 questions:
am I not seeing external activity simply because there's so much head-space?

Is there any reason that the dip tube would stop picking up because the pump was slowed down too much? Is there some difference in how I need to empty the kettle with a pump vs gravity?
My working assumption is that I'm getting air in the dip tube assembly somewhere and broke the siphon so-to-speak, but I tightened everything up way tight, and I've never had a problem with this before.

thanks for any tips or suggestions

 

[VikeMan]

Bottom line, is I only got ~3 gallons in the fermenter. It's a 6.5 gallon anvil fermenter, so there is a ton of headspace. I'm not seeing any blowoff or activity.

so 2 questions:
am I not seeing external activity simply because there's so much head-space?

All other things being equal, less wort and a larger headspace would delay the first visible airlock/blowoff bubble, but not for very long.

 

[Broken Crow]

As to the diptube.. If you have a bazooka on it, it will suck air well before reaching the bottom. The popular Hop-Stopper or even no filter at all allows a diptube to reach 1/4" or less from the bottom pot surface... I have a stainless mesh pancake I sewed with 304 SS thread that I use myself, with the diptube carefully cut with a leg keeping it about 3mm above the mesh which contacts the bottom of my keggle, which leaves about 8oz's before it starts taking on air. In a regular flat-bottomed pot, that'd be a lot more. Take and post pictures of your setup, inside and out, and you'll get a bunch of respones here that have likely experienced the same thing.

 

[PCABrewing]

My working assumption is that I'm getting air in the dip tube assembly somewhere and broke the siphon so-to-speak, but I tightened everything up way tight, and I've never had a problem with this before.

I agree with Broken Crow and I think you have reached the same conclusion.
It only takes one good gulp of air and that pump lost prime.
I have pumps but I transfer from the kettle to the fermenter with gravity because I can slow the flow down enough to not need a bazooka or similar. With a pump you are inclined to use a higher flow rate that makes the bazooka more appropriate but as you see introduces its own issues.

I also tip the BK slightly as the level gets low and I am able to get all but ~a cup or two of the wort.
Yes I do get some trub into the fermenter but not enough to be an issue, most stays in the kettle.
The fermenter is a conical so the trub settles out to the bottom of the cone within an hour or so and is cleared when I do my first yeast dump at about 2 days into fermentation.

 

[ringneck]

I've got the pump located well below the BK output to help keep the pump primed

The dip tube is nearly touching bottom. I Just slide a tube strainer over the whole assembly. Yes, it comes up off the bottom just a little bit more with the strainer, but the level that was left was well above the bottom of the dip tube. it was about halfway up the 45 degree elbow.
(Note, I didn't use the new electric BK yet because I'm waiting for an outlet install. I used my old burner fired BK)

Is there anything other than Teflon tape that people use to help seal the assembly?

 

[PCABrewing]

I've got the pump located well below the BK output to help keep the pump primed
View attachment 761363
The dip tube is nearly touching bottom. I Just slide a tube strainer over the whole assembly. Yes, it comes up off the bottom just a little bit more with the strainer, but the level that was left was well above the bottom of the dip tube. it was about halfway up the 45 degree elbow.
(Note, I didn't use the new electric BK yet because I'm waiting for an outlet install. I used my old burner fired BK)

Is there anything other than Teflon tape that people use to help seal the assembly?
View attachment 761364View attachment 761365

The purpose of Teflon tape is to aid in achieving a seal with the taper pipe thread by lubricating the assembly and allowing you to get the taper tight enough. Of course it does provide some residual sealing ability but it is intended to facilitate the mechanical connection. Despite the popular use. A leak that small probably wouldn't be enough to break the prime. It's more likely that the problem was due to cavitation at the dip tube end.

 

[PCABrewing]

With trub starting to accumulate around the bazooka, that may have focused flow on the easiest route .
If there was enough, it may have turned the bazooka into a tunnel and caused it to draw air in at the high end, near the elbow.
It likely would have made one gurgle as the air got in and then prime was lost, and your pump sped-up a bit.
Did you hear it start to spin faster?

 

[ringneck]

I wasn't listening enough honestly to hear if the sound changed

If there was enough, it may have turned the bazooka into a tunnel and caused it to draw air in at the high end.

That is a great theory. It would explain why it failed now due to the forced pull of the pump from within the tube but worked when gravity was pushing everything down to the opening even if it went a little slower as the filter clogged up.

Thank you!

 

[Bobby_M]

Two things. First, the screen will clog most directly in front of the opening of the diptube and then it will pull tight and take the rest of the screen out of the equation. The other thing that may be happening is that the screen is going to get pretty clogged and then it will suck all the liquid from inside the screen tube and then suck air.

Long story short, you don't need a screen. If you feel you must use it, you will have to drop the flow down to a trickle for the last gallon. If your process yields less volume into the fermenter than you really want, compensate by increasing your batch size by the missing amount next time. It's that simple.

 

[Beholder]

My bet is on cavitation killing your prime when the bazooka plugged, but could also easily be a poor seal in one of the connections that pulls air when the bazooka plugs.

As I didn’t see a whirlpool arm in the pics, if you put in one of those and whirlpool for 10 minutes with 10 minutes settling, you can get a nice trub cone formed in the center that would keep most from your dip tube inlet, which is already nicely off center. This would allow you to get rid of the bazooka filter and the loss of prime problem.

 

[ringneck]

My new system has a whirlpool arm. Was going to go through some old threads to see how that all works. If I understand it right, at flameout I'll start the whirlpool, which I'll also run through the CFC line to get it to sterilization temp. it'll add ~20 minutes to the total time it takes to get from Boiling temp down to pitch temp

 

[Beholder]

My new system has a whirlpool arm. Was going to go through some old threads to see how that all works. If I understand it right, at flameout I'll start the whirlpool, which I'll also run through the CFC line to get it to sterilization temp. it'll add ~20 minutes to the total time it takes to get from Boiling temp down to pitch temp

You’ve got the basics captured. I actually prime the cfc during the boil and cycle it a couple times (if you run continuously supplying boiling wort through your pump, you will cavitate in the pump and damage the impeller) so I can ensure sufficient time at high temp for sterilization of the line.

With whirlpool also serving as your CFC cooling time, provided cooling is longer than 10 minutes, then it really only adds the settling time to the overall elapsed time. Check that your pump gives good flow rate with the CFC, as I found with mine that one riptide got bogged down and could spin 20 gal of wort effectively. When I put my second pump in after the CFC, get a really nice whirlpool going.