Whirlpool

[wes1977]

For those that are using a pump for their whirlpool. What flow rate do you have? I have 19L/min but think I need something a little more manly!

 

[Dan Pratt]

If your doing a single batch the kettle volume for whirpool would be approx 25L so in 1 minute you would have recirculated 80% of the wort. Even for a double batch that is plenty IMO, usually whirlpool from 10 to 20mins.

Why would 19L/min not be enough?

 

[wes1977]

I Whirlpool for about 30mins with little impact!! Perhaps it's my technique?

 

[MHB]

It isn't so much a question of L/m as m/s the velocity of the liquor, the shape and direction of the return to the kettle, the amount of crap like pipes and fittings in the kettle that impede whirlpooling and the shape of the kettle itself.
So just to cover the basics of whirlpool design: -
The pot should have smooth surfaces with no protruding plumbing that will cause eddy currents which will interfere with the whirlpooling action
The best shape (for small/home brewers) is a flat bottom vertical sided "pot" where when full the wort is between 1:1 and 1:2 diameters high
Wort entry is best at not more than 1/3 of the fill height and at 10o in from the tangential
The velocity of the wort return should not exceed 3m/s, any faster and you start to mush up the flock that you formed during boiling, this makes settling slower and gives less effective wort/trub separation - negating the why we whirlpool in the first place.

Given you are pumping at 19L/minute, your wort return velocity (lets do it all in seconds)
19L/m is 0.317L/s
If your return was say a piece of 1/2" copper pipe (pretty common among home brewers) the inside diameter (ID) would be (well the Bunning's annealed copper is 10.88mm ID) the Area (Pir2) and we want all the units to be metres and seconds
Volume is 3.1666x10-4 m3/s
Diameter is 0.0188m
From Velocity = (4*flow rate)/(Pi*diameter2)
Velocity = (4*3.1666x10-4)/(Pi*0.010882) = 0.0012666666664/0.0001183744 = 3.4m/s

So I'm going to say you don't need a bigger pump, in fact it might be causing problems and you really need to look at some of the other features of whirlpool design.
Maybe even wind the pump back a bit or use a slightly lager return
Mark

 

[wes1977]

Have you got any photos of your setup you don't mind sharing?

 

[MHB]

I mostly brew on a small (nano) commercial system, it isn't here so not today, point being it would be the most boring pick of all time, "stainless pot with two holes" One in the bottom near the edge, one in the side about 75mm up from the bottom (tangential) - importantly nothing else.
Mostly do 120L batches, kettle loss is around 2-5L depending on the beer and how much I need another couple of litres...

Just went had a troll through Google images, really couldn't find anything that was the same the closest was this one in a home brew talk thread.

Without the copper pipe, its a good whirlpool. I am startled at how many really bad whirlpool designs there were out there. I suppose its no surprise that people spend so much time and money on false bottoms, hop spiders and the like when you see how crappy most of the designs are.

There should be nothing in the kettle/whirlpool but wort, no pickup tubes, pipe return lines, elements, thermo wells...
Make it super simple let it finish moving and draw down slowly.
Mark

 

[wes1977]

Thanks for your detail replies, greatly appreciated. For my whirlpool I suck up from the bottom using the main drain tap. Do you recommend having a separate one sucking in the correct direction?

 

[wes1977]

My cone looks nothing like that...... That one looks set, mine is all loose and across the who kettle! Should I use more whirlfloc?

 

[MHB]

Not really, I doubt there is a "Right" direction, mine is near the edge pointing down through the floor of the kettle, the return is at the side and looks like a big ellipse.
Plenty of Whirlpool/kettles have the pickup on the side (streak) , usually close to the bottom. Quite a few larger commercial whirlpools have a couple of pickups down the side, as the wort clears from the top, you can draw off from higher up if it's important to speed up throughput..

Some of the more modern dedicated whirlpool are getting a lot wider than they are tall, numbers above were fro a whirlpool kettle (which is what most of us have) typical modern whirlpools are quite shallow 1:0.8 being average, but as low as 1:0.25 (H)

Mark

Edit
Whirlfloc wont make the trub cone, it really helps to settle it faster and tighter, if you have a messy trub cone look to your design.
M

 

[wes1977]

 

[wes1977]

The above pic is my homemade effort realising the science involved. As you can see the in and out are quite close to each other.

 

[billygoat]

The above pic is my homemade effort realising the science involved. As you can see the in and out are quite close to each other.

Are you whirlpooling while the wort is hot or are you whirlpooling after chilling in the kettle, ie- using an immersion chiller?

 

[Fat Bastard]

I've had some experience with power whirlpooling on a homebrew scale.

Initially i stared using the ubiquitous Little Brown Pump, and a gooseneck type device that would allow me to vary the height and angle of the wort return to get the best cone. I found the best height was approximately 1/3 of the way to the bottom, 30 degrees to the tangent and angles slightly upwards.

I've since made it a permanent arrangement with a bigger pump (Ultimiser) and dedicated inlet & return fittings in the pot. It gets a cone happening with a 10min whirlpool and 10 min stand, despite having all sorts of turbulence causing fittings and a dirty great element in the kettle. I think the best aid to whirlpooling is probably a decent sized vessel, under 50l just seems to be too small for the velocity at the edge of the vessel to get to the point where it creates a compact cone.

Don't get me wrong, mine works, and works well enough to so the job, but a properly dimensioned vessel wild make it far easier!

There is some pics of it floating around the forums if you care to search. If I can find a pic, I'll post it later.

 

[wes1977]

I whirlpool hot, is that my mistake?

 

[wes1977]

Should it look like this during the whirlpool?

 

[wes1977]

No sorry, I whirlpool cold.

I remove the chiller and leave it whirlpooling for about 30 mins.

 

[billygoat]

These photos show the effects of whirlpooling while the wort is hot, and whirlpooling after the wort has been chilled in the kettle.
Even though there are 2 elements, a pick up tube and a return arm, when I whirlpool while the wort is hot I get a good cone formation.
I use a March 809 and usually have that going for about 15 mins and then let settle for about 20 mins.

 

[MHB]

There are two types of break material, Hot break coagulates and settles relatively quickly and easily. Cold break on the other had is very light and fluffy, settles very slowly and wont form a nice compact trub cone even if you wait for a ridiculously long time.
Fortunately Cold break isn't an issue for us, it is only a matter of concern if your malt and/or adjunct provides a very large protein load, if you are using good brewing ingredients and doing the basic processes properly you can forget about cold break.

Personally I go the some lengths to keep hot break out of my fermenters. Whirlpool, counter flow chill on the way to the fermenter, pitch yeast...
If you are using an immersion chiller it becomes a lot harder to tell where cold break ends and hot break starts. If you do a brew or two on your system and run the hot wort of to a no chill cube you should get a pretty good feel for how much you need to leave in the kettle to make sure you aren't drawing in the hot break, then just go with that and forget about the cold break. Wort is pretty cheap, even if you budget an extra litre of loss just to be sure, you will end up with better beer.

One other factor that can make a big difference to your break formation and the way it settles is Calcium, giving your location as Australia makes it hard to give any advice on your water, but it might be worth adding some extra (say 50-100ppm) of Ca late in the boil, use a good kettle fining (I like BrewBright) but there are plenty of other products out there. Remember that with all kettle finings More Isn't Better! there is a right dose that will give the best result.

Good luck and hope you get good beers
Mark

 

[DJ_L3ThAL]

The velocity of the wort return should not exceed 3m/s, any faster and you start to mush up the flock that you formed during boiling, this makes settling slower and gives less effective wort/trub separation - negating the why we whirlpool in the first place.


[]

Mark that's really interesting, Once the wort is down to about 90C I use a stainless round bar with a 100mm long tee piece welded to the end, put that into my electric drill and just run it as fast as I can for a minute as fast as I can without splashing /sucking air into the centre of the whirlpool and let that settle for another 10-15mins. It appears to settle out as a reasonably tight cone and I get pretty clear wort (using Whirlfloc).

But am I potentially stirring in hot break particles which won't settle out and are less visible? Or is this hot break formed during the boil quite visible if it remains stirred into the wort?

 

[MHB]

Hot break once has formed (and any that is going to form has by the time the wort has cooled to 90oC) it's a bit like snowflakes, they will settle. What determines the rate that they settle is described by Stokes Law, if you have a play with the variables turn out that the bigger the flock particles are the faster they settle.
By creating high sheer forces (turbulence...) inside some types of pumps or by frappeing the crap out of the wort, you will break the flock into smaller bits that will take longer to settle.
You would be better off replacing the 10mm crossbar with something like a piece of 50x150-200 flat sheet and not spinning the drill too fast, just a little faster than the liquor is rotating, ideally slowly increase the speed of the stirrer as the rotation of the wort picks up, or use a really big spoon.
Mark

Stokes Law, good read