Insulation musings

[iijakii]

I used to BIAB a long time ago. Had a few towels I'd wrap it up with, always had big temp loss.

Going back to BIAB soon, and I do not want to recirculate at all. My initial thought is to make a 3-sided box out of various foamboard/reflectix insulation to just set down over my kettle. I might even use a heat lamp in there (already have spare) to try and buffer some heat loss as well.

That seems very simple and likely very effective to me. Might try reflectix jacket instead. Not sure.

Anyone have any good insulation experience? Please only post if you have quantitative experience. I know common mantra is wrap a sleeping bag around it but my experience with that has been... OK.

 

[timdillon36]

A few more details might b helpful, like batch size. A big batch will have more thermal mass and loose temp slower. Smaller batches can b insulated easier. I do 3gal BIAB on the stove in a 5gal pot and while that is heating to strike temp I set the oven to 170. When I get to mash temp I move the pan to the oven and turn it off. In the time it takes to put the pot in the oven it drops a few degrees and my mash has held steady within 1 or 2 for 1.5 hrs. I am really loving this for small batches. For bigger batches u can always use your cooler MT and the bag for a LT. but I know that's more stuff to use and clean and isn't really single pot BIAB. As far as insulating a big pot I would.think u would need a 5 sided box although a round ridged structure that closely fits your pot might work better. Or a false bottom in the pot and temp control?

 

[RM-MN]

How long is it taking for conversion in your batches? You may find that instead of worrying about the temperature loss during an hour long mash, you might be better off mashing for a shorter time and not worrying so much about the temperature loss at an hour. I'd suggest you use iodine to test for the remaining starches at 10 minutes. Make sure to include some of the grain particles, not just wort.

Note: Do not conclude that you can mash for 10 minutes just because the conversion is complete. My experience with the short mashes is that you can get conversion quickly but you will lack the flavors that the caramel grains or darker specialty grains impart. I would recommend no less than 20 minutes and 30 would probably be better.

 

[TexasWine]

I second what RM-MN said. 30 minutes has become my default mash time. I always hit or overshoot my gravity and have zero problems with attenuation.

 

[jason.mundy]

I used to BIAB a long time ago. Had a few towels I'd wrap it up with, always had big temp loss.
That seems very simple and likely very effective to me. Might try reflectix jacket instead. Not sure.

I've had good experiences with reflectix. I get three wraps around the kettle with notches cut out for the ball valve.

Save the extra reflectix form the roll to have for wrapping a 5 gallon keg. It will keep a keg cold for hours. No jockey box needed.

 

[jmpreiks]

Since Reflectix requires an air gap to really be effective, I have been thinking about attaching a bunch of vertical "ribs" of hard foam or something to the inside of a reflectix wrap. Maybe 2" thick ribs or something like that.

You'd have to have a decent seal on the top and bottom of your kettle though or the air gap will have a lot of heat transfer due to natural convection. The ribs could support lid covered with reflectix with a small air gap, but my biggest challenge is the bottom of the kettle since I use a freestanding burner. I guess I could take it off the burner but I don't like doing that. One option is to add some soft foam strips horizontally between the ribs at the bottom of the reflectix jacket. That should seal decent enough. The entire bottom of the kettle will still be exposed to the air, which happens anyways with the traditional sleeping bag/towel methods.

 

[jmpreiks]

Please only post if you have quantitative experience.

Oops I missed this part... I clearly haven't done what I was pondering about.

 

[iijakii]

Yeah, should have specified - Primarily 5gal batches, some 10s. 15 gal pot. Will definitely start trying out 30min mashes.

Still liking my box idea! Feel like it'd be simple and have a good air pocket buffer in there. I'll probably dick around with a reflectix jacket but being electrical there's just more and more stuff to cut notches for.

 

[tennesseean_87]

I currently mash in a bucket and have no noticeable temp loss unless I open up to stir. I used a cheap foam camping pad to insulate the bucket. I also cut a round lid from 2" extruded polystyrene (SOF chiller leftover) that floats on top of the mash, eliminating headspace in MT (I used this in a kettle doing BIAB, too). The floating top is nice because I have a hole poked in it for a thermometer.

 

[jason.mundy]

I currently mash in a bucket and have no noticeable temp loss unless I open up to stir. I used a cheap foam camping pad to insulate the bucket. I also cut a round lid from 2" extruded polystyrene (SOF chiller leftover) that floats on top of the mash, eliminating headspace in MT (I used this in a kettle doing BIAB, too). The floating top is nice because I have a hole poked in it for a thermometer.

Do you have a picture of it?

I think you are just talking about insulating foam board.

 

[LostHopper]

I used to BIAB a long time ago. Had a few towels I'd wrap it up with, always had big temp loss.

Going back to BIAB soon, and I do not want to recirculate at all. My initial thought is to make a 3-sided box out of various foamboard/reflectix insulation to just set down over my kettle. I might even use a heat lamp in there (already have spare) to try and buffer some heat loss as well.

That seems very simple and likely very effective to me. Might try reflectix jacket instead. Not sure.

Anyone have any good insulation experience? Please only post if you have quantitative experience. I know common mantra is wrap a sleeping bag around it but my experience with that has been... OK.

Could heat loss be a function of the kettle and the insulation? I use a surplus winter sleeping bag with great success even on windy days, which means almost every day in Oklahoma.

 

[tennesseean_87]

Do you have a picture of it?

I think you are just talking about insulating foam board.

Of the camping pad or the floating lid? If the lid, I don't off-hand. Its the foam board insulation from which people build ferm chambers, etc.

 

[Jim311]

For a long time I'd been saving a big Styrofoam cooler for just such a use. I threw it away because I figured I was just being a hoarder and now I wish I had it. Seems perfect for what were trying to do. I still wonder if the temp loss is all that crucial since it does take a long time for 7 gallons of liquid to drop in temp. I might also go the foam wrap route since its basically the same thing.

 

[Jim311]

I just saw a post of a 'tun cozy' and got an idea to use expanding foam. I guess basically I'd wrap my kettle in plastic and place it into a large cardboard box. Then I'd fill the air space around the kettle with expanding foam. Once the foam was near being dry I'd pull the kettle out. Then wait for the foam to dry and have a perfectly shaped 'coozy' for my kettle.

 

[Gavin C]

Anyone have any good insulation experience? Please only post if you have quantitative experience. I know common mantra is wrap a sleeping bag around it but my experience with that has been... OK.

Is this what you're looking for?

Reflectix, Silver tape and some bolts. ~$30

Works great for single infusion full-volume mashes, step infusion mashes and decoction mashes. It's gotta come off for steps in direct fired step-mashes.

Comes on and off in seconds. Simple. The lid can stay insulated throughout. I keep it on till I get to a boil and then off with the lid of course.

 

[hopkincr]

I use a quilted moving blanket and set my pot on it and then fold it all around. I have an 8 gallon pot and it's usually pretty full. Little temp loss (1-2 degrees) in an hour.

 

[BlueHouseBrewhaus]

+1 for Reflectix. My BK is exactly 16" tall so I have a length of 16" wide Reflectix that wraps 3 times around it (with cutouts for the handles) and uses self-adhesive velcro tabs to secure it. Two layers cut in circles insulate the lid. I typically lose 1 - 2 degrees over an hour with stirring every 15 min.

BTW, you don't need ribs to create an air space. The point of Reflectix is that the insulating air space is built into its structure.

 

[wilserbrewer]

Worth mentioning IMO. A mash will take up to approx. 5 minutes for the temp of the grain and strike water to stabilize. I feel people often report a false temp loss owing to this. If one were to mash in, stir well for say 30 seconds and take a temp, I believe this will lead to a false high temp, and then perhaps they feel they are losing heat during the mash, while actually I believe they hastily took a temp too soon before the grain fully absorbed the heat of the strike water and the mash temp was stable throughout.

I would always suggest doughing in and mixing well, then let the mash sit for a few minutes, mix very well again and then take a temp.

This will produce a more true temp of the mash. I have played with this a bit, and have found it takes way longer with much more stirring to produce an even temp throughout the mash, much more so than one would think.

I think this is perhaps the reason reports vary widely on mash temp losses even given similar equipment.

A few wraps of electrical heat tape / cable (the product you wrap pipes to keep from freezing) under the reflectix could likely balance what little heat loss you do find. Just an idea....

 

[jmpreiks]

Worth mentioning IMO. A mash will take up to approx. 5 minutes for the temp of the grain and strike water to stabilize. I feel people often report a false temp loss owing to this. If one were to mash in, stir well for say 30 seconds and take a temp, I believe this will lead to a false high temp, and then perhaps they feel they are losing heat during the mash, while actually I believe they hastily took a temp too soon before the grain fully absorbed the heat of the strike water and the mash temp was stable throughout.

Good point for sure.

 

[ODI3]

I have a 100 L Megapot 1.0 that I use for brewing 20 gal batches ebiab.

The kettle has a tri-ply bottom. I use black bungee cords and moving blankets around the perimeter and a blanket or towel draped over the top. If I really feel motivated I will have the kettle sit on some a folded blanket or towel, but not usually.

The problem with reflectix is that it is plastic, the tape gets old, can melt, hard to clean and isn't free, wereas the blankets are free (kinda) can just be thrown in machine when they get dirty.

I ended up just giving the reflectix away.

 

[Kharnynb]

I've been using an old goose down duvet to just wrap around, losing about 1 degree Celcius in an hour mash, which is safely inside any margin of error.

 

[IslandLizard]

Since Reflectix requires an air gap to really be effective, [...]

Why would that be necessary?

If so, when using multiple layers, the 1st layer is the "air gap" for the second layer, and the 3rd layer has 2 air gaps, etc.

I use 2 layers of regular bubble wrap, the large bubble kind, to insulate my kettle during the boils. Works pretty well.

Having an induction plate, there's no worry for anything to melt or catch on fire.

 

[jmpreiks]

Why would that be necessary?

If so, when using multiple layers, the 1st layer is the "air gap" for the second layer, and the 3rd layer has 2 air gaps, etc.

I use 2 layers of regular bubble wrap, the large bubble kind, to insulate my kettle during the boils. Works pretty well.

Having an induction plate, there's no worry for anything to melt or catch on fire.

Multiple layers definitely helps but you'll still be losing heat through conduction. This is why the high quality metal thermos' keep hot for hours but the crappy ones keep hot for minutes.

See the note about multiple layers here:
http://www.reflectixinc.com/basepage.asp?PageName=What+About+R%2Dvalues%3F&PageIndex=389

Also see the spacers in the top picture here, which are required for good R value on ducting. Similar to our application.
http://www.reflectixinc.com/basepage.asp?Page=HVAC+Duct+Insulation+%2D+R%2D8%2E0&pageIndex=784

 

[IslandLizard]

Multiple layers definitely helps but you'll still be losing heat through conduction. This is why the high quality metal thermos' keep hot for hours but the crappy ones keep hot for minutes.

See the note about multiple layers here:
http://www.reflectixinc.com/basepage.asp?PageName=What+About+R%2Dvalues%3F&PageIndex=389

Also see the spacers in the top picture here, which are required for good R value on ducting. Similar to our application.
http://www.reflectixinc.com/basepage.asp?Page=HVAC+Duct+Insulation+%2D+R%2D8%2E0&pageIndex=784

Interesting read, thanks for the links!
I now understand better how it works while being so thin. It's the R-value of the total system, air gap plus Reflectix cover/shield.

I've found fiberglass to be one of the best insulators, but it's bulky and loses its insulating capabilities as soon as it gets wet. Actually it then becomes a heat conductor, draining energy.

I wonder if Reflectix would benefit when applied as a shield around a neoprene jacket, without an additional air gap. There's still some conduction though.

 

[jason.mundy]

From reading on the reflectix site, Reflectix has an R value of 1.1 per layer when there is not an air gap.

 

[balrog]

Ok. Read this instead of posting essentially same question. Moving from stovetop out to garage on propane with new 10G kettle for BIAB.

Can you *REALLY* wrap reflectrix around something you just had on a scorching propane burner?? Isn't it just aluminized bubble wrap that would melt at a pretty low temp. I just see in my mind a mess of plastic melty nasties around the bottom of my BK.

OP, I personally like the idea of the foam-board set-over box. I did a foam-board box to go around on/around a dorm fridge for a simple fermentation chamber, and it does a fair job, so I'm thinking that's the way to go

 

[iijakii]

Ok. Read this instead of posting essentially same question. Moving from stovetop out to garage on propane with new 10G kettle for BIAB.

Can you *REALLY* wrap reflectrix around something you just had on a scorching propane burner?? Isn't it just aluminized bubble wrap that would melt at a pretty low temp. I just see in my mind a mess of plastic melty nasties around the bottom of my BK.

OP, I personally like the idea of the foam-board set-over box. I did a foam-board box to go around on/around a dorm fridge for a simple fermentation chamber, and it does a fair job, so I'm thinking that's the way to go

According to the site Reflectix has a temp range up to 180F, so it's fine for a mash jacket.

Yeah I'm still thinking the foamboard box is the way to go as well. I'm a couple weeks out from my pot so it'll be a bit before I get around to it. I also need to insulate a couple conicals, just going to do some knockoff reflectix like stuff for that so I'll have some leftover. Maybe I'll do a foamboard box with that stuff on each side for waterproofing. Shiny.

 

[balrog]

When I did 5G pot mashing, pseudo-BIAB, partial boil, whatever; my 5G BK with a paint strainer bag was my mash tun as well. I just used standard 1-2qt/# ratio instead of BIAB. Anyway, it was perfect fit in a large cube-ish cooler I have and I just had to dough in and then put the BK into the cooler and close the lid and it held temp for an hour very well (1-2°). That's why I think a foamboard, no drafts, box would work well.