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Thread: External calandria in wide kettle/whirlpool

  1. #1
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    External calandria in wide kettle/whirlpool

    I'm wondering what people think of designing a kettle/whirlpool with an external calandria for a 15 bbl system. How technologically advanced would this device need to be? Would I need a modulating steam valve, for example? What design considerations do I need to keep in mind?

    Is there any issue with the fact that the wort would only be about 25" deep, but would be 75" wide, in terms of boiling?

    Currently I'm attracted to the idea because, though it is more expensive, the ability to have a flat bottomed, wide whirlpool should allow me to recover more wort for a given grain bill, which should be able to pay for the calandria, but only if it isn't crazy expensive!

    Any advice would be great!
    Last edited by pbraul; 02-07-2019 at 03:27 PM.

  2. #2
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    There are smaller external systems that exist currently. I don’t like them on anything 30bbl or less myself. Just extra parts to clean or break. If you are looking for shorter boil times, higher evaporation rates, and better energy effiency at a 24 hour production facility, then they most certainly have merit.

    I’d opt mash filter if you are looking to benefit from higher material efficiency.

  3. #3
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    Thanks for your reply UnFermentable!
    You're right there are definitely other ways of increasing brewhouse efficiency, but for the purposes of this discussion I did want to stick to the concept of external wort boilers.

    Quote Originally Posted by UnFermentable View Post
    There are smaller external systems that exist currently. I don’t like them on anything 30bbl or less myself. Just extra parts to clean or break. If you are looking for shorter boil times, higher evaporation rates, and better energy effiency at a 24 hour production facility, then they most certainly have merit.
    Do you know anyone running an external wort boiler on one of these smaller systems? Do you have any specific examples of a facility that has experienced major downtime because of their kettle design? It would be super helpful to hear from anyone running an external wort boiler on a 10-20 bbl system.


    Quote Originally Posted by UnFermentable View Post
    I’d opt mash filter if you are looking to benefit from higher material efficiency.
    I'm familiar with mash filters, but we won't be installing one at this location. My questions remain mostly about tank geometry for whirlpooling in a kettle. What are the downsides of a very wide tank, other than space?

  4. #4
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    Why do you want a very wide shallow kettle / whirlpool?

    The optimum wort depth to diameter for whirlpool operation has been shown to be around 0.7 to 1.0 Much variation from that ratio diminishes the settlement of the trub and increases losses.

    Don't forget that WPs work best with pellet hops or a mix of pellets and extract, so the total vegetable / trub loading leaves a clear ring round the edge of the cone. Whole hops don't work as well as pellets as they don't form such a dense cone, so your losses go up.

    You will probably also have to pump the wort continuously as to thermosyphon (and switch the recirc pump off) needs a considerable vertical height to the shell & tub heat exchanger. This is another reason for not using whole hops.

    Personally, at this size, I would stick to offset heating jackets to help get a rolling boil, and then pump round as a separate process at the end of boil for the WP process - not forgetting to recirculate periodically thoughout the boil as well to make sure all the wort is sterilised ad stabilised.
    dick

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    Thanks for your help!

    Quote Originally Posted by dick murton View Post
    Why do you want a very wide shallow kettle / whirlpool?

    The optimum wort depth to diameter for whirlpool operation has been shown to be around 0.7 to 1.0 Much variation from that ratio diminishes the settlement of the trub and increases losses.
    If you have any reading material I would love to have at it. I'm just basing this on Kunze (recommending 3:1 width:height) and the dimensions of 15 bbl whirlpools from the quotes I've received from Krones and Kaspar Schulz this year.

    Quote Originally Posted by dick murton View Post
    Don't forget that WPs work best with pellet hops or a mix of pellets and extract, so the total vegetable / trub loading leaves a clear ring round the edge of the cone. Whole hops don't work as well as pellets as they don't form such a dense cone, so your losses go up.

    You will probably also have to pump the wort continuously as to thermosyphon (and switch the recirc pump off) needs a considerable vertical height to the shell & tub heat exchanger. This is another reason for not using whole hops.
    This is what I feared.

    Quote Originally Posted by dick murton View Post
    Personally, at this size, I would stick to offset heating jackets to help get a rolling boil, and then pump round as a separate process at the end of boil for the WP process - not forgetting to recirculate periodically thoughout the boil as well to make sure all the wort is sterilised ad stabilised.

  6. #6
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    To add to the above comments - think about heating the wort and cleaning the thing.

    15 brl - recirculate 7 times per hour = 107 hl / hr

    You need a flow rate of something like 2 metres / second through every heating tube to minimise fouling and allow good heat transfer. - 2 metres / second rather than 1.5 because the fouling is so high, it benefits from flow rates somewhat higher than minimum turbulent flow rates - preferably higher than 2 metres / second.

    Which means -

    2 metres / hr through 1" (25 mm ID) = 29 hl / hr - so you MIGHT just get away with 4 heating tubes in your calandria - 3 tubes would be better

    2 metres / hr through 1.5" (35.5 mm ID) - 72 hl / hr - you MIGHT just get away with two heating tubes

    2 metres / hr through 2" (48 mm ID) = 130 hl / hr - you can't even get away with a single heating tube

    In other words, for effective heating and cleaning - shell and tube calandria for small brew volumes are not realistic
    dick

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    Beg, Steal, Borrow, or even buy a copy of the EBC Manual of Good Practice: Wort boiling. This had a section written by Prof Victor Denk of Weihenstephan, probably the world expert on whirlpools.

    The speed of ca. 3.5 m/s has shown to be the best wort inlet speed. Lower speeds don't form such a compact cone. Higher speeds don't allow the cone to form as well due to the turbulence affecting settlement

    The recommended diameters for the construction of a whirlpool following Denk is 0.7 - 0.8.

    To not disturb the trub cone formation, the run-off of the wort is started on a level which lies higher than the trub cone (1/2 – 1/3 of liquid level) than changes to one in the height of 100 mm over the bottom and finally to the one at the deepest point of the bottom.

    The liquid level in the trub cone must drop with the same speed as the wort level outside the trub cone.

    If the wort level drops faster than the wort can flow out of the trub cone, the wort flowing out of the trub will destroy the structure of the cone.

    I know Kunze says about the diameter / height ratio - but not everyone gets everything right, and in practice, particularly in large breweries, Denk's recommendation work better.
    dick

  8. #8
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    I think your basic premise is flawed that you will some how get more wort from a flat bottom vessel over a cone shaped bottom. This may or may not be true ( I have use both extensively at least twice). Also, you can get a flat bottom vessel that does not contain an external calandria at 15bbl size. If you appropriately size the cone slope and vessel width to your projected hop additions, and place your hop dam and outlet piping correctly, you can get quite effective collection of wort. You can also use a cone vessel to spin and dump hot side hops prior to WP addition if needed.

    Spend that money somewhere else....the constant question of the brewery....would the ROI be better on something else?

  9. #9
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    Quote Originally Posted by dick murton View Post
    Beg, Steal, Borrow, or even buy a copy of the EBC Manual of Good Practice: Wort boiling. This had a section written by Prof Victor Denk of Weihenstephan, probably the world expert on whirlpools.
    Will do!

    Quote Originally Posted by dick murton View Post
    The speed of ca. 3.5 m/s has shown to be the best wort inlet speed. Lower speeds don't form such a compact cone. Higher speeds don't allow the cone to form as well due to the turbulence affecting settlement

    The recommended diameters for the construction of a whirlpool following Denk is 0.7 - 0.8.
    I am wondering if the Denk ratio is the diam : overall height of the vessel, and not diam:height of the wort? I have been talking about the dimensions of the wort. So sorry if I have not made sense because of it! To get a .8:1 ratio of diam to height of wort, my 15 bbl k/wp would only be 4 feet wide and the wort would be almost 5 feet high, so if, as many manufacturers offer, the kettle were sized at 100% excess capacity, it would be nearly 10 feet high!

    Quote Originally Posted by dick murton View Post
    To not disturb the trub cone formation, the run-off of the wort is started on a level which lies higher than the trub cone (1/2 – 1/3 of liquid level) than changes to one in the height of 100 mm over the bottom and finally to the one at the deepest point of the bottom.

    The liquid level in the trub cone must drop with the same speed as the wort level outside the trub cone.

    If the wort level drops faster than the wort can flow out of the trub cone, the wort flowing out of the trub will destroy the structure of the cone.

    I know Kunze says about the diameter / height ratio - but not everyone gets everything right, and in practice, particularly in large breweries, Denk's recommendation work better.

  10. #10
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    Quote Originally Posted by UnFermentable View Post
    I think your basic premise is flawed that you will some how get more wort from a flat bottom vessel over a cone shaped bottom. This may or may not be true ( I have use both extensively at least twice). Also, you can get a flat bottom vessel that does not contain an external calandria at 15bbl size. If you appropriately size the cone slope and vessel width to your projected hop additions, and place your hop dam and outlet piping correctly, you can get quite effective collection of wort. You can also use a cone vessel to spin and dump hot side hops prior to WP addition if needed.

    Spend that money somewhere else....the constant question of the brewery....would the ROI be better on something else?
    Yes, this is what I feared - that there are too many other factors and I might get very good yield with a cone bottom. After all, most people use them with great success, and I have as well.

    I don't know about welding dimple jackets onto a flat bottom though? Our manufacturer said it may cause the flat surface to ripple/warp in unpredictable ways.

  11. #11
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    Wort depth = 0.7 feet / metres / whatever to 1.0 diameter feet / metres / whatever. - shallower than it is deep
    dick

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    Quote Originally Posted by dick murton View Post
    Wort depth = 0.7 feet / metres / whatever to 1.0 diameter feet / metres / whatever. - shallower than it is deep

    I see! It's really interesting... none of the dimensions I have from any manufacturers in my quoting were very close to that number. DME and a few quoted around .63, where NSI was .47 and Premier at .4. As I mentioned earlier Krones is quoting a WP vessel of .35. Wonder why such a huge variance?

  13. #13
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    Depends....

    There are dozens of brewery configurations to choose from. There is no ONE way to do things. Many systems have a whirlpool directly below the lauter tun. Most small German systems are designed this way. So the diameter of the whirlpool is stuck at the diameter of the lauter tun (plus the insulation). So there's an example of a shallow whirlpool. Some manufacturers are stuck with certain available width of stainless sheet. So that tends to set diameters of vessels. Other designs take into consideration that the vessels fit neatly into containers. There are many, many designs out there. AB in St. Louis has a giant room full of whirlpools of different designs. Nobody has the perfect answer. There is no magic ratio.
    Phillip Kelm--Palau Brewing Company Manager--

  14. #14
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    send me a private message. i have just commissioned a brewhouse which i had built in boucherville, with a whirlpool that works well. if you can get to toronto, you can come see it.

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