Full-boil benefits with BIAB?

[applescrap]

We are good then.

Absolutely!

 

[MaryB]

Again, why does the electronics industry use aluminum to remove heat from solid state devices? Because it is the best heat conductor for the price/machining. Once heat is to the material air interface you have the exact same thermal conductivity. But since stainless moves that heat slower to the outside than aluminum will it will retain heat longer. And cook whatever I am trying to cool on the other side. Real life example that has been used for YEARS on consumer grade electronics. Are there better materials that conduct heat? Yup, copper being one of them but it is more expensive, harder to machine and work, tends to be softer and reacts more with acids/bases...

Im sorry, i didnt mean any offense.

I dont understand though why i only can find conductivity information and charts not dissipation. It makes sense thermodynamicly quick in quick out, but i wonder if i took these two pans in my hand outside here in clorado snow storm and put on porch which would cool first. I figure it wouldn't matter much compared to the thermo retainment property of a really thick 1070 wort in them. I was hoping someone could produce a figure comparing wort retention vs. metal, my reading says 10x thus the wort mass maintains biab mash not the metal, i wrap mine in feathers and a plastic bag.

 

[RM-MN]

How can something conduct heat better if it doesn't shed it? Do you have any understanding of thermodynamics or are you just parroting stuff you read somewhere? If the material does not shed the heat it does not conduct it, it merely absorbs it.

Exactly, the difference in conductivity between the aluminum and stainless steel is almost nil since the sides of the kettle are thin. When you start thinking of wall thickness in inches instead of thousandths of an inch it makes a difference. With the same shape the two kettles will shed heat at about the same rate with the stainless being slightly smaller because of the polished surface. Paint both of them black and the radiation of both of them will be essentially the same.

Aluminum makes great heat sinks because it is cheap and can be easily molded or machined to any shape. Copper would make a better heat sink because it conducts heat slightly faster and silver would be better yet but you don't see either of those used because of the cost/benefit ratio. Stainless steel isn't as good of a conductor but if it could be molded/machined cheaper it would be used for heat sinks because the distance the heat needs to travel is small.

 

[fun4stuff]

https://imgur.com/a/xgNB2

 

[MaryB]

Actually that thin metal DOES make a difference! Even the thermal transfer compound that is spread in layer that is less than .01 thick can totally change the thermal transfer properties. Silver bearing compounds move heat FASTER and that is what counts! The speed at which the material can move heat from one side to the other makes a huge difference and aluminum does it far better than stainless.

Exactly, the difference in conductivity between the aluminum and stainless steel is almost nil since the sides of the kettle are thin. When you start thinking of wall thickness in inches instead of thousandths of an inch it makes a difference. With the same shape the two kettles will shed heat at about the same rate with the stainless being slightly smaller because of the polished surface. Paint both of them black and the radiation of both of them will be essentially the same.

Aluminum makes great heat sinks because it is cheap and can be easily molded or machined to any shape. Copper would make a better heat sink because it conducts heat slightly faster and silver would be better yet but you don't see either of those used because of the cost/benefit ratio. Stainless steel isn't as good of a conductor but if it could be molded/machined cheaper it would be used for heat sinks because the distance the heat needs to travel is small.

 

[jr72023]

Actually that thin metal DOES make a difference! Even the thermal transfer compound that is spread in layer that is less than .01 thick can totally change the thermal transfer properties. Silver bearing compounds move heat FASTER and that is what counts! The speed at which the material can move heat from one side to the other makes a huge difference and aluminum does it far better than stainless.

I don't know about you but, I certainly don't own a silver boil kettle.

Yes, aluminum does transfer heat better than stainless steel (SS). That is why I commented that it, consequently, cannot hold heat better. You must, however, take into account that the thickness of the average aluminum pot is much higher than the thickness of a SS pot. Consequently, it is not apples to apples. However, aluminum will still transfer heat faster in such applications in BOTH directions even though the aluminum kettle will have much more mass. (Aluminum thermal conductivity 200-250 W/moC vs 304 stainless steel 16 W/moC)

Thermal properties are not the reason stainless steel is often chosen for industrial grade applications like large cooking vessels or fermentation vats. It is normally chosen because of its tensile strength, hardness (resistance to scratches from rough use and cleaning), and resistance to chemicals, both acidic and alkaline, used in cleaning. Additionally, stainless steel can withstand much higher temperatures without adverse affects.

Simply concentrating on heat conductivity is not productive as I seriously doubt that anyone here made that their sole criteria for a purchase.

One poster said they chose aluminum because of the price. He has other hobbies he also would like to spend money on. I can respect that. I would imagine that a lot of people who choose aluminum do so for the same reason and that is a very valid point. Aluminum will definitely save them money and make excellent beer. It will last for years if it is properly cared for.

I, personally, chose SS because I am lazy. I use copper and steel mesh scrubbers as well as scotchbrite pads to clean my kettle very fast and do not have to worry about scratching the polished surface. I can scrub that thing hard and furious without marring the finish. I sell fire trucks and like bright shiny objects. Were I to scrub aluminum in the same way I would be removing material and dulling the finish. But, that was my choice.

As I have said, either material will make great beer. The kettle is just a tool in the brewer's toolbox. I like nice tools. They give me peace of mind and one less thing to worry about. But, that is just me.

Now, can we drop the AL vs SS subject and get back to the original topic: Full Boil Benefits of BIAB?

 

[MaryB]

Oh I prefer stainless for longevity and ease of cleaning too. Just finished a 5 gallon batch 3 hours ago, filled with my 145 degree tap water, added PBW, soaked for 2 hours, hit it with a scotchbrite pad to get a few stains off and done. No worries about cleaner discoloration or the scotchbrite taking off the oxide layer. Tossed the cooler coil into the pot as it soaked and after a rinse it came out looking like I polished it! I too like things shiny clean!

 

[JohnnyBrewGood]

Triclad exists for a reason right?

Correct me if I am wrong but I have never seen an aluminum pot with SS added to the bottom, but rather aluminum added to SS.

I don't know what that means, just wanted to see if I could stir it up again.

 

[jr72023]

Triclad exists for a reason right?

Correct me if I am wrong but I have never seen an aluminum pot with SS added to the bottom, but rather aluminum added to SS.

I don't know what that means, just wanted to see if I could stir it up again.

The reason Triclad exists is to entice us tool snobs to spend more regardless of actual, provable benefits.

Just a thought.

 

[MaryB]

Triclad adds an aluminum disc in between 2 layers of stainless. It helps spread the heat more evenly across the bottom of the pot. Is it worth the expense? I haven't scorched a boil yet(yet!!) in my cheap thin stainless Bayou deep fry pot.