Downsides of a Penrose Kettle?

[defenestrate]

Damn. I emailed them on Friday to ask them a question about having an extra hole drilled so I could place an order and was wondering why they hadn't got back to me. This probably means they'll up the price or something

i wouldnt assume that, they are pretty backed up and can take a couple days to respond. once they do they have great customer service.

 

[Homer]

Sell it to me so I can use it on my gas burner now and then when you get a gas burner they'll probably be back in stock and have a flatter bottom.

Tempting... but I think i'm gonna try and build a heat stick first, and see if I can boil with the heat stick + stove.

 

[Bruin]

Okay, got tired of waiting. Email and voicemail requesting notice when Penrose kettle would be available, no reply to either. It's been a few weeks. Order placed with Austin Homebrew supply for the Polarware 42 quart kettle w/ball valve, 240 bucks including shipping. Bought a hose barb nipple for the ball valve from them too, that was extra. I got beer to brew damnit, summer's coming. So in response to the title of this thread, "downside to Penrose kettle", I guess the downside would be you can't buy one!

 

[DaleP]

Sorry about that......we are very busy, and doing everything we can to catch up and ship. I have also tried very hard to answer everyones emails as best I can. Apperently I missed one. A couple weeks back we realized that we were way behind. Rather than collect peoples money and sit on it till we caught up, we shut down that part of the website. Do to building up some stock, we have Brewhemoths about, but the kettles disappeared way too fast.
Dale Penrose

 

[JEBrew]

Dale beat me to it...

Thanks for all your interest and we promise to be back up to date on the kettles soon!!

Cheers!

Josh

 

[bwiens]

Will you be making the 22gal kettles when you get caught up?

 

[neovox]

On the other hand.... Congrats on your success guys. ::

 

[Bruin]

Got your email today Dale. No problem man. Sorry I couldn't wait. And I appreciate all the winter weather problems you've been having at work, believe me!

 

[importdude]

I bought one... works great...

 

[JEBrew]

Got your email today Dale. No problem man. Sorry I couldn't wait. And I appreciate all the winter weather problems you've been having at work, believe me!

Being in Jersey, I bet you understand completely! We don't get it as bad in St. Louis, but Dale is in charge of Maintenance, so it snows and he is here at about 4:00 in the morning!!

 

[Hex]

+1 for the 22 gal. version.

 

[jeffzx9]

I can Attest to their quality and customer service. The kettles are heavy duty contruction and customer service is excellent.

 

[smokinghole]

Well I got the email tonight and have an order placed. This thing should make my boil off less with a 15.75" diameter vs my current 18" diameter pot. I'm looking forward to possibly using it over spring break!

 

[Jaysus]

I wish I got in on this at the old price... but a good buddy of mine called the extra $20 a snoozing penalty - and I guess I agree with him.

 

[StMarcos]

The boil off rate doesn't have anything to do with the diameter of the opening.

 

[motobrewer]

what's the wall thickness?

what's the bottom thickness?

thanks.

 

[Bruin]

Wouldn't the ratio of surface area to volume be a factor in boil off rate? As it is not an enclosed vessel like a boiler, only the surface exposed to air is where the liquid can make a transition to gas (steam), so one would intuitively assume that a gallon of water would boil off faster in a frying pan than it would in a narrow and tall vessel.

 

[smokinghole]

The boil off rate doesn't have anything to do with the diameter of the opening.

I beg to differ. Do me a favor. Fill a 20"x20" pan with a gallon of water. Then fill a 2" cylinder with 1 gallon of water. Then check back here and tell us which one is dry first.

 

[StMarcos]

That's from evaporation, not boiling. Different principle. 2260J/g, and that's coming from the flame/element.

 

[Bruin]

I just read a lengthy thread on the boil topic. So lengthy I didn't get everything done SWMBO wanted done before she got home. Now I"M in hot water!

 

[AnOldUR]

I just read a lengthy thread on the boil topic.

Care to share what you took away from it?

 

[smokinghole]

You're talking strictly vaporization at 2260J/g and when we're boiling in a pot like we do there's both vaporization and evaporation.

If I lived 2000ft below sea level my pot wouldn't boil until it's past 212F. The heat simply allows the molecules of water to liberate themselves from the liquid much easier which is why a pot of hot water (not boiling maybe 200F) has considerably more water vapor than an ambient temp pot of water. So I think it's perfectly safe to say with a certainty that pot diameter is a big part in the boil off/evaporation rate.

 

[jeffmeh]

Boil-off rate is absolutely a function of the surface area of the kettle opening. In fact, at sea level, one can approximate the gallons boil-off per hour = pi * r squared * 0.007289791872. [Note the absurd precision on the constant, lol].

 

[WhiskeySix]

I beg to differ. Do me a favor. Fill a 20"x20" pan with a gallon of water. Then fill a 2" cylinder with 1 gallon of water. Then check back here and tell us which one is dry first.

Boil-off rate is absolutely a function of the surface area of the kettle opening.

This.

Boil that gallon of water in the 20"X20" pan and the 2" cylinder and see which one gets dry first.

 

[StMarcos]

Look at an example. Keep it easy at say we have an immersion element. Find how much power you need to maintain the wort at a little under boiling. This is equal to the heat lost around the perimeter of the vessel. I don't know what it is, say 1000w. Any and all power put into the system, above and beyond this value, goes into vaporizing the water. Add another 1000w (J/s), and you are vaporizing 1000/2260 = 0.44g/s. Add another 1000w and you will vaporize 0.88g/s.

That's roughly 3.5L/hour.

Seems clear as rain to me.

 

[WilliamWS]

Boil-off rate is absolutely a function of the surface area of the kettle opening. In fact, at sea level, one can approximate the gallons boil-off per hour = pi * r squared * 0.007289791872. [Note the absurd precision on the constant, lol].

Thanks for the info. I, too just bought one of these kettles and was just figuring it would take me a batch or two to get my new boil-off rate. This equation really helps my initial estimate. Just to be sure, though: I'm assuming this equation is using inches, correct?

 

[jeffmeh]

Look at an example. Keep it easy at say we have an immersion element. Find how much power you need to maintain the wort at a little under boiling. This is equal to the heat lost around the perimeter of the vessel. I don't know what it is, say 1000w. Any and all power put into the system, above and beyond this value, goes into vaporizing the water. Add another 1000w (J/s), and you are vaporizing 1000/2260 = 0.44g/s. Add another 1000w and you will vaporize 0.88g/s.

That's roughly 3.5L/hour.

Seems clear as rain to me.

The vapor needs to escape the vessel, which is dependent upon the surface area of the exit point. Empirically, we experience different boil off rates in different diameter vessels, regardless of whatever thought experiment one may conjecture.

 

[Bruin]

jeffmeh, I'm with you, but the earlier thread on this is here:
https://www.homebrewtalk.com/f39/boil-off-rate-192966/
Arguments were making my head spin. My Dad's a physicist, I'm gonna cut to the chase and ask him.

 

[StMarcos]

If you're dumping that extra heat in there, the vapor will exit through a 1'' tube just fine, and at the same rate to boot.

 

[jeffmeh]

Thanks for the info. I, too just bought one of these kettles and was just figuring it would take me a batch or two to get my new boil-off rate. This equation really helps my initial estimate. Just to be sure, though: I'm assuming this equation is using inches, correct?

Yes. In my setup, the kettle diameter is 17.375 in, so my approximate boil-off rate is =PI() x (17.375 in/2)**2 x 0.007289791872 gal/hr/sq in = 1.73 gal/hr. There is some variation based upon ambient humidity, boil vigor, etc., but this should get you pretty close.