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Considering the best trub cone formation in the wort (settling in the center), what aspects shall we have in mind when designing a serpentine (coil) to chill wort (immersed in it) with whirlpool (re-circulation) like Mr Malty Chiller ?

I think that the solid residues need some space to pass between chiller tubes and space between the bottom of the kettle and the coil to decant in the center.

Is it true ? How many space is needed ? And what about to elevate the coil with 3 rods instead leaving a ring of the own coil tube in the bottom ?

Assuming all samples below with the same tube area, what would be the best design ?

1) Dense with a ring in the bottom

Dense in the bottom

2) Dense with a ring in the bottom but elevated in the middle

Dense elevated

3) Sparse with a ring in the bottom

Sparse in the bottom

4) Sparse with a ring in the bottom but elevated in the middle

Sparse elevated

5) Dense elevated by rods

Dense elevated by rods

6) Sparse elevated by rods

Sparse elevated by rods

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3 Answers 3

up vote 1 down vote accepted

I agree with Denny that it should not matter much in reality, but in theory at least I'd say that the sparse coil may be the favored option.

The effectiveness of your chiller depends (amongst other factors) on the steepness of the heat gradient or, if you will, the temperature contrast between the chiller and the immediately surrounding liquid. The larger the temperature contrast the more energy can be transferred from the wort to the cooling water per time unit.

The wort will be chilled radially from your tubes and if the coils are closely packed they will together cool the immediately surrounding wort rather quickly, thus decreasing the heat exchange. A sparser coil formation will reduce this cooperative chilling of only the wort close to the tubing and increase the heat dispersion throughout the entire liquid.

This effect is the entire reason that using the whirlpool feature (or just plain old stirring) is so beneficial and the stirring of the liquid will have a much greater effect than the spacing of the coils. Even so, when I built my own i made sure to space the coils as much as possible while still making sure that the entire chiller would be immersed.

In conclusion: I vote for option 3 for its combination of simplicity and theoretical function.

Edit: The coil itself does not center any trub, its the movement of the liquid.

The velocity of the moving liquid is much greater at the edges of your pot then in the middle and so the heavy particles gathers in the middle as it would require more energy to accelerate them than the surrounding water.

The cooler would thus be more of an obstacle to trub formation than a help as one might first believe and so yet again the sparse formation would be the better option. However with this in mind your legs in figure 6 might not be a bad idea.

Once again however: I don't think that all this thinking will much improve the final product or greatly simplify any part of the process, fun as it is.

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"...i made sure to space the coils as much as possible while still making sure that the entire chiller would be immersed", sure, I agree. But the coil spaces wouldn't help to center the trub ? –  Luciano May 9 at 16:37
    
Edited to incorporate information about trub formation. –  Korsbo May 9 at 17:57
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My experience is that, no the spaces won't help in centering trub. –  Denny Conn May 9 at 18:01
1  
I'm quite sure that you are right Denny and that non of these elaborate measure will help much with anything. But for us thinkers and tinkerers the theorizing and optimizing is part of the fun and it increases the sense of achievement and pride when finishing the product. I hope I have not been unclear in my post that I don't believe elaborate chillers will perform much better than their somewhat cruder counterparts. If you however have experience that really contradicts the hypothesis above that would be interesting. –  Korsbo May 9 at 18:17

Ya know what? In reality, it just doesn't matter. I drop the same old funky immersion chiller I've been using for years into the wort. Then I take the output hose from my pump and clamp it to the side of the kettle, pointing kinda sideways below wort level. It's equally as effective as a friend's setup that's similar to a couple of your designs. Don't overthink it.

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But what about a new one ? Which shape to choose ? Some recommendation ? –  Luciano May 8 at 19:21
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What I'm getting at is that you can choose any of those options and it will be equally effective. –  Denny Conn May 9 at 15:16

In my experience, I never get a trub cone with the chiller in place. And I don't think you will. Too much turbulence as the wort whirlpools for a nice clean pot centered cone of trub.

Of course the turbulence leads to great chilling via a great turnover of wort volume and surface area contact with the chiller.

I only get a nice cone in a standard pot with no chiller in plate, and NO DIP TUBE (also causes turbulence).

Jamil started this method to maximize chilling, not trub cone formation. I think this has become an over interpreted tool in the homebrewing community.

You'll have to whirlpool for the cone post chill. Pro pots whirlpool in smooth sides vessels with recessed drain ports, then draw from the side. Its simply physics.

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I agree to the extent that I do it for the faster chilling. The trub formation is a side benefit. –  Denny Conn May 9 at 16:14

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