Slow Run Off From Kettle

[brewerben]

Hi all,

I've got a modified 98L kettle (purchased from beer belly) and I have been having touble getting a good run off into a 19mm helical wound hose. Opening the ball valve completely, even with a full kettle results in very slow run off. There is clearly air trapped inside the hose, and most likely the valve and welded nipple. This air is unable to escape back up into the kettle or be forced out via the hose.

I use a beer belly deluxe pick up with hop screen, but even in testing with a kettle FULL of water and with the pickup removed I still get the problem.

The current means of overcoming this problem is to lift the hose above the level of the tap, but below the level of the wort/water in the kettle. This then forces the air out of the hose and on lowering the hose I then get the full flow rate possible (for that diameter hose). This works, but is a pain, quite literally when dealing with hot wort

Anyone else had an issue similar to this? Know how to solve it?

NOTE: I don't believe it's got anything to do with the equipment as this is a pretty standard arrangement, and reckon Wayne has sold a bunch of these things. Additionally his workmanship is superb etc. I only mentioned the source of the kettle so people would know exactly what design I'm refering to.

Thought I'd put it out there before I drag my kettle out to BB for a trouble shoot.

Cheers,
Ben

 

[raven19]

Air could be cavitating in the fittings possibly?

I think I have a similar issue when racking - the tube isnt quite at full capacity. Once it gets some pressure at the bottom (i.e. bottom end is submersed) it seems to get better and speed up.

You mentioned helical wound hose - this could be your problem, if its not moving fast enough, air could be getting trapped in the high points on the first few coils, and stuffing up your flow speed?

Can you purge it of air (i.e. fill with boil or sanitsed water), cap the bottom, connect to kettle tap, runoff this water into a bucket until wort starts to run out, then turn off tap, switch outlet to your fermentor/cube, and you are away!?

Just my 2c.

 

[brewerben]

Can you purge it of air (i.e. fill with boil or sanitsed water), cap the bottom, connect to kettle tap, runoff this water into a bucket until wort starts to run out, then turn off tap, switch outlet to your fermentor/cube, and you are away!?

Hi Raven19,

Thanks for the suggestion and yeah that's possible, but I'd rather just be able to open the tap because ultimately I will be running it out into a march pump. The pump doesn't like there being any air in the line (not self priming) and disconnecting the hose from the pump is a pain (even though I'm using cams).

It would be nice just to open the tap, crank the pump and away we go (pump will be mounted well below kettle outlet to ensure priming, once I sort this weird air problem out).

 

[muckey]

I think it'll be best to ask beerbelly. He'll probably be able to help over the phone anyway and will probably set you straight very quickly.

 

[KHB]

Im having the same problem with my keggle using a beer belly hopstoppa, i am buying new helicoil hose tomorrow and have changed my fitting from garden connects as i think i may be getting some air in there. Hoping it fixes the problem.

KHB

 

[domonsura]

This little issue presents itself when the kettle has not been filled via the pickup tube. The hopscreen itself is not to blame, it's just the shape that the pickup must be to sit the hopscreen on the floor that traps a small air bubble. Try actually filling the kettle via that fitting (ie: the pickup tube), and you will find that the small airbubble will be evacuated in the process.
I fill my kettle via the pickup fitting in the first place, evacuating the airbubble in the process.

The other solution is to turn the whole pickup & hopscreen 'up' for a moment after the kettle has been filled and open the ballvalve momentarily so the airbubble can escape back up into the kettle (should happen very easily) and then just push it back down with mash paddle etc. Once this has been done at the beginning of the brew, the pickup tube will stay primed unless the kettle has been emptied and air allowed to re-enter the tube.
Not a particulary complicated problem, but a pain in the backside all the same - unfortunately there isn't really a way to make the pickup tube so this doesn't happen - by nature it has to have a curve in it.
Hope this helps.

 

[brewerben]

This little issue presents itself when the kettle has not been filled via the pickup tube.

Hi Wayne,

Thanks for the resposne. Unfortunately I get this issue without either the hop screen or pickup tube installed, this happened during a dummy run I did with just water as I was trying to isolate the exact source of the problem. And I do fill my kettle from the mash tun pushing back through the ball valve into the pick up tube etc.

I will do another dummy run with water tonight and take a couple of photos...

Ben

 

[captaincleanoff]

had this exact problem last night with my beerbelly gear.

I couldn't get any flow from the kettle when my hose and chiller were connected. Disconnected the chiller, just used hose. Still nothing..

Then I took the hose off and tried pouring directly out of the kettle tap with nothing attached. This worked.

Why would it flow ok directly out, but not through hose?

 

[domonsura]

uhhh....not quite sure on that one, I've never experienced an issue like that. but it might be related to a slight bit of back pressure in the hose in conjunction with a small airbubble in the back of the valve preventing the syphon effect from getting started?.......I'll take the pickup/hopscreen out of my one and have a muck about tomorrow. I'm assuming that these kettles have full bore valves installed? (standard issue on the brewkettles we send out).

 

[Mantis]

I had this problem as well on tuesday after I got the hole drilled in my pot and the ball valve and pickup tube installed. I did a test boil of water to check the plumbing then into a cube with the hose. First run went really slow and didnt syphon below the tap level. I guess air lock so I tightned the ball valve on the bulk head and the hose tail..
Poured the water back it and tried again. Still went very slow and I had to raise the tube above the tap level to get it to fill and syphon properly. But at least this time it took it all out to the bottom of the pickup tube.
I took the ball valve and hose tail off today and put some thread tape on to try to eliminate air getting in there.
Goning to do my first AG in this pot on Saturday BIAB. So I will fill to above the tap via the tube and see if this helps

 

[brewerben]

uhhh....not quite sure on that one, I've never experienced an issue like that. but it might be related to a slight bit of back pressure in the hose in conjunction with a small airbubble in the back of the valve preventing the syphon effect from getting started?.......I'll take the pickup/hopscreen out of my one and have a muck about tomorrow. I'm assuming that these kettles have full bore valves installed? (standard issue on the brewkettles we send out).

Hi Wayne

Yes, I have the standard full bore set up.

Your explaination of what might be happening is kind of what I was thinking but I wonder if the air is getting stuck against the reducing nipple used to connect the pick up to the welded socket. During my water testing I left this nipple screwed in and removed the pickup tube at the ferrule fitting (so when I say I did my testing without the pickup connected, I was only 99% truthful ).

This nipple has 10mm ID on one end, while the other end has an ID of 15mm. As you know, the 10mm end faces outwards, i.e. towards the tap and this in itself will act as a kind of bore reduction. It is here that I think the air is stuck and unable to exit back up through the kettle nor down the hose when the head pressure is not enough, or maybe when there is some kind of back pressure as you suggest.

I ran another test with 80 odd litres of water in the kettle and have good and bad news... The good news is the air bubble in the hose vanished before I had the chance to get the stupid fully automatic canon crap camera to focus on something other than the corrugated iron shed wall.... However it was definitely there for a while. This scenario doesn't worry me, just as long as it does get forced out!

However, I ran it down to about 30L, stopped the flow, disconnected the cam fitting with my drain hose, cleared that, reconnected, and started again. Then the problem reoccured and it never fully cleared. Strangely this flow (albeit not a siphon) was better than usual as sometimes I get a miniscule trickle... I think the kettle knows I've posted on this forum and is trying to make me look stupid(er).

I have no issues with my HLT using one of your weldless bulkheads B)

When I need to water my veggies again I will put anoter 80L in the kettle and try it without the nipple to see if it improves...

Ben

 

[Kai]

There's also air in the hose, that might be what's staying there as you start your transfer and it'll block the flow somewhat. When that happens to me I just pinch off the hose lower down for a second, release and repeat till the liquid pushes out ok.. Although you can't do that with a helical wound hose...

 

[KHB]

This little issue presents itself when the kettle has not been filled via the pickup tube. The hopscreen itself is not to blame, it's just the shape that the pickup must be to sit the hopscreen on the floor that traps a small air bubble. Try actually filling the kettle via that fitting (ie: the pickup tube), and you will find that the small airbubble will be evacuated in the process.
I fill my kettle via the pickup fitting in the first place, evacuating the airbubble in the process.

The other solution is to turn the whole pickup & hopscreen 'up' for a moment after the kettle has been filled and open the ballvalve momentarily so the airbubble can escape back up into the kettle (should happen very easily) and then just push it back down with mash paddle etc. Once this has been done at the beginning of the brew, the pickup tube will stay primed unless the kettle has been emptied and air allowed to re-enter the tube.
Not a particulary complicated problem, but a pain in the backside all the same - unfortunately there isn't really a way to make the pickup tube so this doesn't happen - by nature it has to have a curve in it.
Hope this helps.

Hi Dom,

i do fill via the pick up tube.

KHB

 

[BOG]

I get this problem.
Start the drain of the kettle but air is caught in the line. Wort dribbles passed around the bubble but there is not enough syphion effect to pull the bubble through the hose to get a full flow.
I partially open the tap holding the hose high above the wort level slowly lower the hose and wait for the hose line to fill then drop the hose in the cube (no chill) and the amount of fluid in the hose provides enough suction to pull the bubble through and away we go.

Alternate is to open tap. and blow into hose (obviously no boling wort in hose and hot wort no issue of infection) it blows out bubble and the resulting rush of wort back down the line to fill the tap length starts the syphion effect.

Key here is you need to have sufficent hose on the tap to get a syphion effect rush to pull the bubble through. Short hose and you will neeve get the bubble to clear.

Another way is the bend (kink) end of hose. open tap wait for the dribbleing wort to fill hose remove kinck , the weight of the water in the hose pulls the bubble out.


BOG

 

[captaincleanoff]

today I tried filling the kettle through the tap as suggested.

I noticed that the water was only coming through the top holes of the hop screen (from beerbelly)

should it be exiting through all the holes, or is it just being forced out of these holes for some reason. I'm thinking this may be why I am getting slow run off

 

[razz]

brewerben, I used to have this problem when I had a gravity set up from the kettle through two chillers coils and into my fermenter. I figured there was a lot of air trapped in there, approx 14mtrs of 1/2" copper plus fittings and other hoses. I ended up using one of those rubber primer bulbs that are used for priming fuel lines in an outboard motor, works a treat ! I placed it on the very bottom hose running into the fermenter and pumped the priming bulb until I felt the wort coming through.