This is how i reduced my headspace in my masttun

[Kmcogar]

This is how i reduced my headspace in my mash tun. It was pretty simple and worked really well. It's hard to say how much it made my efficiency went up. I used this headspace reducer as well as hybrid sparging for the first time. My brew came out to 91% efficiency.

 

[kh54s10]

That looks pretty good. I wonder though if it really had much to do with the gain in efficiency.

I preheat my tun, stir in the grain, check and stabilize the temperature then close it up. The most I have lost in 60 minutes is 2 degrees. So don't think I will be making one. For me it would be another thing taking up space on my porch.

 

[kh54s10]

It is kind of nice for holding your thermometer though!

 

[Pilgarlic]

And why are we concerned about headspace in a mash tun?

 

[BrewingReverend]

I guess I dont get the point. I usually only lose about 1 degree during my mash. I would also be very worried about the plastic tape and the hot water.

 

[ekjohns]

I have done the same thing in my igloo cooler. I was losing 6 degrees over an hour for 5 gal batch. With the foam floating lid I lose 3-4. Most people that only lose 1 degree brew 10 gal batches which have much more thermal mass

 

[Pilgarlic]

I do five gallon batches and lose 1-2 degrees. Igloo ten gallon round.

 

[HangLoose]

And why are we concerned about headspace in a mash tun?

Head space will have a big effect on heat loss. If you are loosing much heat, trying to reduce your head space would likely help.

 

[Pilgarlic]

Head space will have a big effect on heat loss. If you are loosing much heat, trying to reduce your head space would likely help.

I supposed that was the objective. Doesn't pass my smell test, though. I can't imagine why headspace would have any but a marginal effect on heat loss in the mash. Wouldn't take more than seconds for the heat of the mash and the dead space to reach equilibrium. After that, it's all up to the insulating quality of the tun itself.

 

[HangLoose]

It's just more surface area to radiate heat to the environment. It's not a big deal but since people get hung up over a degree or two they want anything that helps.

 

[BargainFittings]

A lot of coolers do not have insulation in the lids so this would mitigate that a bit.

Some spray foam in the lid works wonders.

 

[ekjohns]

Another thing is the lids are not insulated so they lose a lot of heat. The styrofoam is a much better insulator

 

[ekjohns]

Some spray foam in the lid works wonders.

If you can get it to expand I have tried it on several cooler lids and the foam always collapses on itself

 

[Pilgarlic]

The lid is the lid. The question is whether filling the headspace with styrofoam is a benefit. The best insulation is trapped air. Styrofoam insulates because of its trapped air. What's "headspace" in a mash tun but trapped air? In fact, it's more trapped air than the styrofoam. I'll grant that the lid may be a problem. I don't believe the headspace, though, is.

 

[barryfine]

The lid is the lid. The question is whether filling the headspace with styrofoam is a benefit. The best insulation is trapped air. Styrofoam insulates because of its trapped air. What's "headspace" in a mash tun but trapped air? In fact, it's more trapped air than the styrofoam. I'll grant that the lid may be a problem. I don't believe the headspace, though, is.

I think that too much headspace can most certainly lead to a lot of temperature loss. If you were doing a 5 gallon batch in a 20 gallon mash tun I'm sure you lose a lot more temperature than if you did it in a smaller vessel. Am I convinced that this is completely necessary in this setup? No, but the reasoning behind seems sound to me.

 

[Pilgarlic]

I think that too much headspace can most certainly lead to a lot of temperature loss. If you were doing a 5 gallon batch in a 20 gallon mash tun I'm sure you lose a lot more temperature than if you did it in a smaller vessel. Am I convinced that this is completely necessary in this setup? No, but the reasoning behind seems sound to me.

I disagree. The mass of that air in the 15 gallons of headspace is negligible compared to the mass of the 5 gallons of mash. With a preheated mash tun, and probably even without, the effect would be negligible. Now, if you want to try a "reductio ad absurdum" argument, here, I'm sure there is a point at which the amount of headspace would become significant. But the ratio of mash to headspace would indeed have to be absurd, I think.

 

[DeafSmith]

The lid is the lid. The question is whether filling the headspace with styrofoam is a benefit. The best insulation is trapped air. Styrofoam insulates because of its trapped air. What's "headspace" in a mash tun but trapped air? In fact, it's more trapped air than the styrofoam. I'll grant that the lid may be a problem. I don't believe the headspace, though, is.

The problem with a lot of headspace is that you get convection currents in the air. Hot air rises up from the mash, loses heat at the top, then the slightly cooled air, being heavier than the hot air sinks back down to pick up more heat from the mash, etc. The air trapped in insulation can't move like that.

 

[Pilgarlic]

The problem with a lot of headspace is that you get convection currents in the air. Hot air rises up from the mash, loses heat at the top, then the slightly cooled air, being heavier than the hot air sinks back down to pick up more heat from the mash, etc. The air trapped in insulation can't move like that.

Why would the currents you describe increase the rate of loss through the cooler?

 

[Pilgarlic]

Because without the filler in the headspace the average differential between the cooler wall and the inside air in contact with that wall is greater, increasing conducted heat loss. I'll buy that. But it's a tempest in a mash tun. No big deal. I won't bother. I STILL lose only a degree or two in an hour in my 5 gal batches in a 10 gal cooler.

 

[weirdboy]

I have done the same thing in my igloo cooler. I was losing 6 degrees over an hour for 5 gal batch. With the foam floating lid I lose 3-4. Most people that only lose 1 degree brew 10 gal batches which have much more thermal mass

I, too, use an Igloo (an Ice Cube) and brew mostly 5 gallon batches. I only lose about 1 degree during a typical mash, barring extreme weather conditions. A cold, dense fog will suck the heat right out of it, but on a typical SoCal brewday I don't have any problems holding mash temps.

Although, nowadays I have been doing more BIAB than anything else.

 

[HangLoose]

The lid is the lid. The question is whether filling the headspace with styrofoam is a benefit. The best insulation is trapped air. Styrofoam insulates because of its trapped air. What's "headspace" in a mash tun but trapped air? In fact, it's more trapped air than the styrofoam. I'll grant that the lid may be a problem. I don't believe the headspace, though, is.

So I guess if you just blocked off your attic vents you wouldn't need insulation in your attic?? By your logic nearly all insulation is useless, why have insulation in your walls when you could just make sure there are no drafts? Headspace isn't the problem, its a piece of the insulation puzzle.

 

[Pilgarlic]

So I guess if you just blocked off your attic vents you wouldn't need insulation in your attic?? By your logic nearly all insulation is useless, why have insulation in your walls when you could just make sure there are no drafts? Headspace isn't the problem, its a piece of the insulation puzzle.

Funny question. Actually, I'm a builder. We use spray foam insulation on the inside of the roof (the lid) and no insulation on the ceiling. So, I suppose my answer for you is "yes".

 

[Kmcogar]

I didn't realize this post would cause this much discussion. The good part about this extra insulation was no temperature loss. With that in there and the cooler lid closed. It stayed stable. I like it enough to use it again.

Also if your one of those brewers that keep wondering if your temperature is stable, you can easily lift the lid and check on it.

 

[gregkeller]

Not sure the headspace has a huge effect on the sizes we are talking about, but I bet that the lid is by far the most inefficient part of a cooler mash tun. I read a story on here about a guy who sprayed foam into the lid and it never expanded, just stayed gummy and didn't insulate very well because the foam needs air to cause it to expand, which i thought would happen spraying it into small holes in the lid, but who knows. Putting a layer of foam floating ontop of the mash should help if the lid isn't insulated. I have a 10 gallon rubbermaid cooler and sprayed foam into the lid, but the lid is the warmest part of the tun to the touch at the end of 60 minutes, so that's where i'm loosing the most heat from (I lose about 1-1.5 degrees/hr if i put a sleeping bag on my mash tun. I'll probably try and make one of these floating insulators. I just wonder about leaching anything from the foam into my wort. Probably not something to worry about though, since styrofoam is used in coffee cups around the world.

 

[Pilgarlic]

So I guess if you just blocked off your attic vents you wouldn't need insulation in your attic?? By your logic nearly all insulation is useless, why have insulation in your walls when you could just make sure there are no drafts? Headspace isn't the problem, its a piece of the insulation puzzle.

If you thought that I was suggesting that insulation is unnecessary you misread me. I was simply saying that GIVEN a level of insulation in the lid, the marginal effect of the headspace on heat loss would be negligible. I still think so. Anyone who thinks not can do what he likes to address it. I won't. That's all.

 

[Homercidal]

My cooler seems to lose maybe 1-2 points over an hour if I preheat. But, when I did a small batch in it, the loss of thermal mass from the smaller volume of wort allowed it to drop over 5 points. I can see where having a foam cover like this would be a big help.

And I really dig the thermometer running through it too! I could see myself making one just for that feature.

 

[Kmcogar]

Not sure the headspace has a huge effect on the sizes we are talking about, but I bet that the lid is by far the most inefficient part of a cooler mash tun. I read a story on here about a guy who sprayed foam into the lid and it never expanded, just stayed gummy and didn't insulate very well because the foam needs air to cause it to expand, which i thought would happen spraying it into small holes in the lid, but who knows. Putting a layer of foam floating ontop of the mash should help if the lid isn't insulated. I have a 10 gallon rubbermaid cooler and sprayed foam into the lid, but the lid is the warmest part of the tun to the touch at the end of 60 minutes, so that's where i'm loosing the most heat from (I lose about 1-1.5 degrees/hr if i put a sleeping bag on my mash tun. I'll probably try and make one of these floating insulators. I just wonder about leaching anything from the foam into my wort. Probably not something to worry about though, since styrofoam is used in coffee cups around the world.

FYI. It's tight enough against the sides so it doesn't "float" on the wort. It's just right above it. I put a handle on it to pull it in and out. I also taped it up pretty good so none of the styrofoam would get in the wort. Everything held up fine

 

[tre9er]

Bobby-M, didn't you say to use a low expansion foam in the lid, or something like that? I'm thinking of foaming my lid but want the right stuff. Link to common Home Depot-type product?

 

[DeafSmith]

I tried the spray foam insulation on my lid and it didn't expand - actually, it appeared to expand, then later collapse. I have since heard that it needs moisture to work properly, so maybe that is why it sometimes doesn't work when you spray it into small holes in the lid. Anyone tried spritzing a small amount of water in before the foam?

I used the low expansion "Great Stuff" for "Windows and Doors"

 

[Kmcogar]

I originally was gonna use this http://m.lowes.com/mt/www.lowes.com...etInfo=&un_jtt_v_tabs=description#description

But I had the styrofoam so I went with the free route. That stuff is only $3 though. Seems like it would work perfectly