Controlling Wort Flow Through Plate Chiller

[Truman42]

Ive noticed over the last couple of brews ive done that my wort flow through my plate chiller is very slow. The chiller isnt blocked or anything and I have no restrictions through the hosework. (If i pump water through it comes out the other end at the same rate its poured in.) I also use a hop spider and get a good trub cone after whirlpool.
But for some reason even with the tap wide open it just seems to trickle through. Its good in that my wort chills right down to around 11C but takes a good 20 mins or so to fully drain.
I would like to at least get the flow a bit faster so it drains quicker and maybe only pulls down to 18-20C.

In the photo you can see its built up in the hose just before the chiller. Could it be some sort of airlock in the outlet hose from the kettle? Anyone else have this same problem? Interested to hear your thoughts?

 

[fraser_john]

Add a valve on the water inlet to the chiller, control the amount of cold water going in and you should be able to adjust the wort temperature coming out.

Flow rate of wort is probably based on the height difference between the kettle outlet and cold wort outlet and resistance to flow by the chiller is probably high. When you pump water through it the pressure would be enough to over come the resistance.

Try the theory by raising your kettle another 30cm and test it using plain water.

Remember you dont want to drain the kettle too fast as when it gets to the cone you created during whirlpooling, draining too fast will flatten the cone out quickly.

 

[Truman42]

Pumped was probably a bad choice of words, what I should have said was poured water into the chiller at one end it flows out the same rate at the other. The funny thing is that this exact same setup worked fine the first few times I used it and I got full flow if I opened the tap right up on the kettle. I was able to close it back to get a decent enough restriction to allow the wort to cool to a desired temp of around 20C. (and not pull the trub cone through)

Nothings changed since then but I now get restricted flow even with the tap fully open. At the end of the day I can live with it, just curious as to what might be causing the restriction.

Will try what you said and raise the urn and see if that changes anything.

 

[fraser_john]

Does seem odd that it used to work and it does look like there is a major airlock in your hose. Kettle tap all clear, no blockage?

I use a CFC and have to squeeze the outlet tube to make sure it sucks all the air through the lines and then it flows fast enough I have to shut the kettle outlet down to about 3/4 to slow the flow.

What about running the plate chiller rotated 90 degrees and then raise it closer to the kettle, that will give a much larger drop after the outlet that it might help suck any air out inside the chiller?

 

[JDW81]

Ive noticed over the last couple of brews ive done that my wort flow through my plate chiller is very slow. The chiller isnt blocked or anything and I have no restrictions through the hosework. (If i pump water through it comes out the other end at the same rate its poured in.) I also use a hop spider and get a good trub cone after whirlpool.
But for some reason even with the tap wide open it just seems to trickle through. Its good in that my wort chills right down to around 11C but takes a good 20 mins or so to fully drain.
I would like to at least get the flow a bit faster so it drains quicker and maybe only pulls down to 18-20C.

In the photo you can see its built up in the hose just before the chiller. Could it be some sort of airlock in the outlet hose from the kettle? Anyone else have this same problem? Interested to hear your thoughts?

View attachment 56290

From your picture it looks like the wort out hose is above the wort in hose. I'm no hydrologist, but I would have thought you'd get more efficient flow if the wort didn't have to flow against gravity on its way out of the chiller (assuming you don't have a pump connected). Have you tried it with the chiller rotated 180 degrees? Rotating will give effectively give you an extra 30cm or so head pressure. It appears the build up in the hose is just cause the fluid can't flow against gravity (the fluid backup is sitting level with your outlet hose).

 

[Truman42]

Taps all clear, Ive tested it without the hose and it flows fine. Will try it at 90 degrees and see if that helps. Maybe because its trying to push the air down towards the chiller it doesnt have enough pressure to do so as the air wants to naturally rise to the path of least resistance.
If I do as you suggest and give it the shortest path possibe to the chiller once the air reaches this point it will naturally rise to the top of the chiller and through the outlet. Thanks for the tip.

 

[Wolfy]

AFIK putting the outlet on the 'top' is how you want to configure the plate-chiller - because it purges the air inside the chiller, if you put the outlet on the bottom the chiller would be filled with air-pockets and be much less efficient.

Truman, do you run something through the chiller to sanitize it, disconnect the flow/chiller/lines, but dont empty the plate chiller, before draining the kettle?

The reason I ask this is that (more so with my CFC but also with plate-chiller) if there is an air-bubble (not sure how best to explain it) that gets 'locked inside' the chiller or hoses, it can drastically reduce the flow through the chiller, once the bubble is purged things flow as normal.
To get over this, once filled with sanitizing fluid (I just recirculate boiling water) I don't disconnect the lines but run the hot-wort directly through the chiller, discarding the first bit before collecting the wort in the fermentor - that way no air-bubbles form inside the chiller.

 

[JDW81]

AFIK putting the outlet on the 'top' is how you want to configure the plate-chiller - because it purges the air inside the chiller, if you put the outlet on the bottom the chiller would be filled with air-pockets and be much less efficient.

That makes sense. I guess the simplest explanation isn't always the best.

 

[drsmurto]

AFIK putting the outlet on the 'top' is how you want to configure the plate-chiller - because it purges the air inside the chiller, if you put the outlet on the bottom the chiller would be filled with air-pockets and be much less efficient.

Truman, do you run something through the chiller to sanitize it, disconnect the flow/chiller/lines, but dont empty the plate chiller, before draining the kettle?

The reason I ask this is that (more so with my CFC but also with plate-chiller) if there is an air-bubble (not sure how best to explain it) that gets 'locked inside' the chiller or hoses, it can drastically reduce the flow through the chiller, once the bubble is purged things flow as normal.
To get over this, once filled with sanitizing fluid (I just recirculate boiling water) I don't disconnect the lines but run the hot-wort directly through the chiller, discarding the first bit before collecting the wort in the fermentor - that way no air-bubbles form inside the chiller.

Agree. Wort in the top, water in at the bottom.

Gravity is your friend, stop trying to go against her

 

[Truman42]

AFIK putting the outlet on the 'top' is how you want to configure the plate-chiller - because it purges the air inside the chiller, if you put the outlet on the bottom the chiller would be filled with air-pockets and be much less efficient.

Truman, do you run something through the chiller to sanitize it, disconnect the flow/chiller/lines, but dont empty the plate chiller, before draining the kettle?

The reason I ask this is that (more so with my CFC but also with plate-chiller) if there is an air-bubble (not sure how best to explain it) that gets 'locked inside' the chiller or hoses, it can drastically reduce the flow through the chiller, once the bubble is purged things flow as normal.
To get over this, once filled with sanitizing fluid (I just recirculate boiling water) I don't disconnect the lines but run the hot-wort directly through the chiller, discarding the first bit before collecting the wort in the fermentor - that way no air-bubbles form inside the chiller.

To sanitize I pour starsan into the chiller through a short piece of silicone hose. Once its flowing out of the opposite end I connect this hose to that end so I have an enclosed loop. I just turn the chiller up the opposite way every 5 mins or so to fully sanitize it. When Im ready to chill I drain the sarsan and connect the kettle hose straight to the chiller inlet.

How is your chiller seup Wolfy? Same as mine positioned vertically or do you have yours horizontally? Im assuming the wort path inside the chiller is in an S shape so it flows up and down and so on until it gets to the outlet. If thats the case then everyime it wants to flow down its trying to push air and cant so is being restricted?? So i could sanatise with my kettle hose and hook it straight up to the kettle leaving the starsan in the chiller as you suggest. Will give that a test run and see how it goes.

 

[Truman42]

Agree. Wort in the top, water in at the bottom.

Gravity is your friend, stop trying to go against her

Ok but that means you dont agree... Now Im confused??

 

[Wolfy]

How is your chiller seup Wolfy? Same as mine positioned vertically or do you have yours horizontally?

Mine has a different configuration to yours and looks like the Blichmann model - so I run it with all the barbs to the top - but interestingly all the pictures on their website show the chiller on it's side.

 

[mark0]

I have no restrictions through the hosework. (If i pump water through it comes out the other end at the same rate its poured in.)

First, you will always have restrictions, the hose itself is a restriction, and the chiller is definately a restriction.
Second, you have found the law of conservation of mass and the incompressibility of water.

Except for the possible trapping of air (and reduction in area for wort/water to flow), the relative positions of your inlets/outlets won't make any appreciable difference to the wort/water flow rate. The critical part of this setup is the height difference between the wort level in the kettle and the end of the outlet hose (fermenter). You can have all the S bends or loops you like, won't make a difference

Depending on the internal flow paths in your chiller (are they parallel or series paths?? check with manufacturer)
it would be better to have your both inlets at the bottom if possible, so that as the chiller fills the air rises and out the outlet tube.

If that isn't possible with your plate chiller, it's better to have wort at the bottom and garden hose at the top (hose will have more pressure and speed to force air out).
the easiest way to check would be to unbolt/cable tie from your stand and have a play, moving the chiller around, see what works and what doesn't. try rotating in vertical plane to swap inlets/outlets and try laying the chiller flat, noting changes to flow rate and any air expelled.

Mark

 

[drsmurto]

Ok but that means you dont agree... Now Im confused??

Sorry, caffeine blood level dropped below critical.

Sorted now.

If you are relying on gravity in your system it makes more sense to have the wort go in to the top and come out the bottom and your chilling water the opposite. That way you can slow the wort speed down using the tap on the kettle requiring no extra taps etc to adjust the temperature of the wort exiting the chiller.

I have my chiller sitting on its base so this becomes a moot point. Not the most efficient method perhaps but my chilling water is recirculated so no wastage and the temperature of the water is well below 10C at the moment.

 

[PhantomEasey]

Disclaimer: I don't own a plate chiller.

I used to work for an injection moulding company and it was considered good practice to have chilling water lines running from the bottom of the tool (mould) to the top - against gravity.

The theory is that gravity slows the flow of water and causes it to make contact will all surfaces within the cooling line, maximising the cooling effect.

On the contrary, if cooling water is run top-to-bottom (with gravity) the water can separate as it flows, reducing the % contact area between the cooling water and the cooling line within the mould which in turn reduces the cooling effect.

Therefore, I assume having the cooling water running against gravity, and the wort running with gravity, would be the optimum configuration.

 

[Truman42]

Ok might play around with the chiller horizontal instead and also try it with the chiller vertical but the wort outlet at the bottom and inlet at the top, opposite to how I have it now.

@Dr Smurto...My water supply also comes from my water tank via a submersible pump and is recirculated back into the tank so no water wasted. Its not really a problem to let it trickle drain into the fermenter except that it adds another half an hour to my already long brew day, and the wort is getting too cold. Would like to speed it up a tad if possible to be able to regulate my wort temp so its ready to pitch.

(Next project: Add a thermowell to my chiller)

With this brew my starter had also dropped to 12c so wasn't a problem. But usually I pitch at high krausen and starter temp is around 20-22C so chilling my wort to 11C isnt optimal.

 

[JaseH]

How many plates is your chiller? More plates = higher flow. By the looks of it your plate chiller is maybe 10 plates? So that in itself will be a bit of restriction, especially if you are just using gravity to drain the wort.

Doesn't explain the part why it originally flowed better though?

 

[Thirsty Boy]

two things

First - you only need the outlet of the chiller slightly above the inlet, just so that the air is purged out as the chiller fills - as wolfy said, the chiller is much less efficient if it has air pockets in it. But, ideally the outlet should indeed be above the inlet. I sit mine horizontally and simply hold the "out" end a little higher for the few seconds it takes to fill.

It doesn't matter with the water side really, because you can just turn the tap on high for a second and pretty much blast any air pockets out.

Second - siphon... things will flow a lot faster if you make sure your hose from the chiller to the fermenter is completely full and "pulling" the wort through. If its not and the wort is just running down a half full tube, then you lose all the head pressure of the height between your chiller outlet and the top of the liquid in the fermenter.

Start your chilling with the final hose out of the fermenter and the end above the height of the
liquid in your kettle, open the tap and let the wort fill the chiller and the level in the hose equalise with the level of the wort in the kettle. Slowly drop the end of the hose until the wort is nearly coming out the end and then kink the hose, drop it into the fermenter and with luck and a bit of practise, you should have a completely full hose and a proper siphon action. Making sure the end of the hose stays beneath the surface of the liquid in the fermenter will ensure that it stays all locked up.

This can make a really significant difference in your flow rate.

 

[Truman42]

Making sure the end of the hose stays beneath the surface of the liquid in the fermenter will ensure that it stays all locked up.

This can make a really significant difference in your flow rate.

Thanks heaps TB a very good explanation on all things chiller which I will put into practice.

With your comment above, I always let the wort fall from the hose into the fermenter from about half way down so it aerates the wort. Your saying I shouldnt do this and go back to shaking the **** out of that heavy bugger?

 

[Thirsty Boy]

Thanks heaps TB a very good explanation on all things chiller which I will put into practice.

With your comment above, I always let the wort fall from the hose into the fermenter from about half way down so it aerates the wort. Your saying I shouldnt do this and go back to shaking the **** out of that heavy bugger?

not necessarily, just that keeping the end of the hose under the liquid level will both ensure the whole tube stays properly full of liquid and that you get the full effect of the height difference between the liquid level in your kettle and the liquid level in your fermenter. That will help your flow rate.

If you can keep the siphon going properly without the hose under the liquid, then it doesn't matter.

You could get the same effect by moving the plate chiller to the bottom of your brew stand so the liquid has to come back up from it to go over the edge of your fermenter. All you need to remember is that you only get head pressure from the bits of the system that are "full"