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General Category => Equipment and Software => Topic started by: morticaixavier on January 23, 2014, 04:00:39 PM

Title: I've got an idea for an experiment
Post by: morticaixavier on January 23, 2014, 04:00:39 PM
but not the right equipment.

When I was brewing on the 15 bbl system at Thirsty Bear the brewer mentioned that he whirlpools throughout the entire boil because one of the steam jackets on the kettle is less than optimal and it takes a really long time to get to a boil otherwise. but with a whirlpool going the artificial convection speeds things up.

Now on my system the 'whirlpool' is manual meaning I use a silicon spatula to get the mass of wort spinning and then let it settle. I could stir the whole time it's coming up to a boil but I'm just a leeeetle too lazy for that to sound like fun. I know some of you folks have fancy dancy systems with tangential inlets and pumps and... etc.

well I think it would be cool (or perhaps hot?) if you were to start recording time from flame on to boil and see if you can actually achieve faster boils with the whirlpool going the entire time. if so it seems like it should save some propane!

any takers? I'll accept and organize the data!
Title: Re: I've got an idea for an experiment
Post by: hoser on January 23, 2014, 04:21:37 PM
I am planning on brewing this weekend.  I have the JZ Whirlpool setup with a pump.  I have never thought of this before. I may have to try this! Thanks Mort!
Title: Re: I've got an idea for an experiment
Post by: BrewArk on January 23, 2014, 04:35:50 PM
Some variables (boiler dimensions, burner output) can be controlled by using the same equipment for the experiment.  Others (water temp, ambient temp, wind velocity) might need to be documented.

If there is a big enough effect, they might be insignificant, but it would be a shame to come to the wrong conclusion if you were sabotaged by another variable that confounded the results.
Title: Re: I've got an idea for an experiment
Post by: morticaixavier on January 23, 2014, 04:46:18 PM
Some variables (boiler dimensions, burner output) can be controlled by using the same equipment for the experiment.  Others (water temp, ambient temp, wind velocity) might need to be documented.

If there is a big enough effect, they might be insignificant, but it would be a shame to come to the wrong conclusion if you were sabotaged by another variable that confounded the results.

good point. I imagine weather effects would be the hardest to control for. I imagine controlling for volume, gravity, and mash temp would be important as well but those are at least things we have control over.

so I guess our experimental brewers would also have to have access to a brew area with relatively consistent temperatures and wind speeds.
Title: Re: I've got an idea for an experiment
Post by: Stevie on January 23, 2014, 04:50:51 PM
May end up evaporating more than usual, I base this off of line drying clothes on a breezy day compared to a day with little wind, a greater amount of the wort will be in contact with the air. Might only evaporate more while getting up to the boil since the boil does a good job of mixing on its own.

Good idea.
Title: Re: I've got an idea for an experiment
Post by: denny on January 23, 2014, 05:03:27 PM
I'll give it a try...if I remember!
Title: Re: I've got an idea for an experiment
Post by: ynotbrusum on January 24, 2014, 03:02:33 AM
But will it cause hot side aeration!  Just kidding....

Title: Re: I've got an idea for an experiment
Post by: Jimmy K on January 24, 2014, 03:16:29 AM
There's a chance I'm crazy, maybe a good chance. But I've always believed that whirlpooling boiling wort caused the gentle rolling boil to stop and heat to build in the bottom of the kettle until it formed a large, slightly dangerous bubble of steam.  Otherwise, seems like it can't hurt. This could probably be tested with water too.
Title: Re: I've got an idea for an experiment
Post by: klickitat jim on January 24, 2014, 03:51:47 AM
I turn my whirlpool on about 15 minutes before flame out. Kills the boil for a couple minutes but then back to normal boil.

I recirculate my mash with direct heat low flame. On my system if my flame is too high OR if my pump out valve is too open, the mash temp will rise.

If it wasn't so cold out I would go do a water boil test of each method for you. Plus a waste of propane... I suspect the difference will be negligible
Title: Re: I've got an idea for an experiment
Post by: dkfick on January 24, 2014, 04:24:59 AM
Seems to me that it could increase the time it takes to achieve a boil for us because it's not being heated via steam jacket... I'll try and record times over my new few brews and see though... I'm all for trying things to save time during the process... I already whirlpool MOST of the boil to sanitize my plate chiller.... though possibly going through my plate chiller would be another point of delay in achieving a boil...
Title: Re: I've got an idea for an experiment
Post by: kramerog on January 24, 2014, 04:31:38 AM
Thirsty Bear's experience is to be expected.  When water is being heated indirectly by steam, it is the heat transfer from the steel into the water that is rate limiting so stirring the water should increase the speed of heating. 

When a non-condensing gas is used to heat the water (ignoring the condensation that occurs initially which is generally boiled off later), my intuition is that it is the heat transfer from the hot gas into the pot that is rate limiting.  My intuition is based on my rusty chemical engineering memories and the fact that the outside of  the pot being heated is much closer to the temperature of water than the temperature of the combustion gas.  Have you noticed if you use a keggle as a brewpot, you're likely to burn yourself if you touch the bottom skirt but the part of the keggle in contact with the wort is much cooler?

I'll check "Perry's Handbook" too and let you know what it says.
Title: Re: I've got an idea for an experiment
Post by: Jimmy K on January 24, 2014, 04:59:18 AM
Oh, that makes some sense, I think.
 
Also, a steam jacket may be more likely to heat very evenly and form temperature gradients - like an immersion chiller. With a propane burner the heat source is stronger and concentrated in a smaller area, possibly creating stronger natural convection currents.
Title: Re: I've got an idea for an experiment
Post by: kramerog on February 05, 2014, 11:35:42 PM
I checked Perry's Handbook which supports what I say (stirring your boil kettle when heating with steam will decrease time to get to boil while stirring a direct-fired boil kettle does not).   Per Perry's, the overall heat transfer for steam heating water in a tubular heat exchanger is 400-1000 BTU/(F ft2 h) while for atmospheric hot air heating water (closest thing to combustion I could find) it is 10-50. 
Title: Re: I've got an idea for an experiment
Post by: klickitat jim on February 06, 2014, 01:56:46 AM
I've heard that a watched pot never boils.
Title: Re: I've got an idea for an experiment
Post by: morticaixavier on February 06, 2014, 12:18:45 PM
I've heard that a watched pot never boils.

I have actually watched a put till it boiled so I've proven that to be incorrect;)
Title: Re: I've got an idea for an experiment
Post by: HoosierBrew on February 06, 2014, 12:59:49 PM
I've heard that a watched pot never boils.

I have actually watched a put till it boiled so I've proven that to be incorrect;)

+1.  Me too !  My first AG pot was 8 gallons (for 5.5 gallon batches) , so after collecting 7 gallons in the pot, I had to watch that mother like a hawk. Needless to say, I upgraded pretty quickly.
Title: Re: I've got an idea for an experiment
Post by: euge on February 06, 2014, 03:23:49 PM
I've done several recirc's up to and throughout the boil. I didn't see any benefit to it- thought it would reach boiling faster at least. Perhaps on a larger scale it starts to demonstrate usefulness.
Title: Re: I've got an idea for an experiment
Post by: morticaixavier on February 06, 2014, 03:25:25 PM
I've done several recirc's up to and throughout the boil. I didn't see any benefit to it- thought it would reach boiling faster at least. Perhaps on a larger scale it starts to demonstrate usefulness.

Yeah, I suspect that kramerogs assessment is accurate and it has to do with the heat source as well.
Title: Re: I've got an idea for an experiment
Post by: Jimmy K on February 07, 2014, 02:19:46 PM
I've heard that a watched pot never boils.
But an unwatched pot boils over. It's a catch 22.
Title: Re: I've got an idea for an experiment
Post by: scottNU on February 07, 2014, 03:39:26 PM

But an unwatched pot boils over.


That I can confirm.  More than once.  Apparently I needed confirming data.
Title: Re: I've got an idea for an experiment
Post by: klickitat jim on February 08, 2014, 12:20:47 AM
Well it was just something I heard. I guess you really do have to depend on your own experience