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Mashing in igloo

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neon0107

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Hello All,

I am a new BIAB brewer. I have a hard time maintaining mash temp. I wrap with two layers of Reflectix and sometimes throw a sleeping bag over that and still have seen temps drop up to 5-6 degrees. My long term plan is to go E-BIAB so won’t be much of a problem then. Until then I have heard of people doing their BIAB mash in an igloo cooler. I may try this but want to know what you think about proper size. I mainly do 2.5 batches so I can brew more. I do a 5 gallon every now and then just to have a good go to on hand. Was thinking 10 gallon igloo but was not sure if that would be to big with to much headspace for the smaller mashes? I have also heard of people putting aluminum foil over the top of mash to help keep heat from evaporating if there is a lot of head space. Thoughts?
 
There's nothing wrong with putting a little heat under the pot to get your temps back up. Just take all the slack out of the bag and stir well while heating. Coolers are good at holding heat but if you miss the temp initially, you have to mess around with small boiling water additions or removing some liquid to bring to a boil.

Another option is to take all the racks out of your oven, preheat to 170F and then shut it off when you put the pot in there. The higher ambient temps in the oven will slow the cooling of the mash to nothing.
 
...I wrap with two layers of Reflectix and sometimes throw a sleeping bag over that and still have seen temps drop up to 5-6 degrees....

You should be getting much better heat retention than that with a sleeping bag alone, so something is not right. Do you put the lid on the kettle? Do you wrap and tuck the sleeping bag carefully, to avoid places where heat can leak out? Do you leave it alone during the mash? Every time you open it up (to check temp) heat will escape.

I insulate with a 1960's army surplus sleeping bag (i.e. nothing special) and my mash temps stay within 1 degree for a full hour in all seasons except winter. Even during winter only once have I felt the need to add heat.

I carefully tuck the sleeping bag around the base of my burner, and wrap a cord around it so it stays put. I use a thermometer with a remote probe, so I don't have to remove the insulation to check the temp. I don't use a mash cap, since there's no need for me to.
 
Hello All,

I am a new BIAB brewer. I have a hard time maintaining mash temp. I wrap with two layers of Reflectix and sometimes throw a sleeping bag over that and still have seen temps drop up to 5-6 degrees. My long term plan is to go E-BIAB so won’t be much of a problem then. Until then I have heard of people doing their BIAB mash in an igloo cooler. I may try this but want to know what you think about proper size. I mainly do 2.5 batches so I can brew more. I do a 5 gallon every now and then just to have a good go to on hand. Was thinking 10 gallon igloo but was not sure if that would be to big with to much headspace for the smaller mashes? I have also heard of people putting aluminum foil over the top of mash to help keep heat from evaporating if there is a lot of head space. Thoughts?

How long is your mash period? How long does it take to get full conversion. Note that those are not necessarily the same.

With BIAB you have the ability to use grains that are milled much finer than in a conventional mash tun and with that finer milling, conversion happens much faster and then your temperature loss is of no concern. I've tested my conversion time and found it to be less than 5 minutes. Why should I worry if I happen to lose 5 degrees by the end of the hour?
 
Thanks for all the tips and info. I have been putting the lid on and wrapping what I thought was good. I will try wrapping the bottom tighter with a bungie to keep it tight.

I will also look into checking when conversion is done. I would be curious as my crush is super fine.
 
Thanks for all the tips and info. I have been putting the lid on and wrapping what I thought was good. I will try wrapping the bottom tighter with a bungie to keep it tight.

I will also look into checking when conversion is done. I would be curious as my crush is super fine.

There are 2 ways to test for conversion. One is to use iodine. Put a drop of iodine on a white surface and a drop of wort alongside it. Make sure your wort drop has plenty of grain particles as those are where any unconverted starches will be. Mix the 2 and look for color change. If the iodine turns blue, there is unconverted starch.

The second is to check the gravity of the wort. The gravity will change as the starch is turned to sugar. Be sure to mix well before testing. I've found that as the starch turns to sugar the density increases and the sugar laden wort will settle out giving a false reading if taken from the surface without vigorous stirring. I use a refractometer and can measure the difference in gravity from the surface to the limit of reach of the pipette used to collect the sample.
 
Nothing wrong with mashing in a cooler .. BUT .. it isn't cheap. Your small batches can be done in a 5 gallon drink cooler ($20), but you probably want to add a ball valve and gaskets/washers. Alternately, you can just drain back to the BK using an auto siphon. A round 10 gallon cooler (for your 5G batches) is gonna run $50, plus whatever you add in accoutrements (say that like the French .. AH Coo Tre MON .. ). Rectangular cooler cost less, but IMO, are harder to lift and schlep around. Nailing it with the reflectix (since you have some) is the better option, again IMO. Then take the $50 and buy a sack of grain.
 
Hello All,

I am a new BIAB brewer. I have a hard time maintaining mash temp. I wrap with two layers of Reflectix and sometimes throw a sleeping bag over that and still have seen temps drop up to 5-6 degrees. My long term plan is to go E-BIAB so won’t be much of a problem then. Until then I have heard of people doing their BIAB mash in an igloo cooler. I may try this but want to know what you think about proper size. I mainly do 2.5 batches so I can brew more. I do a 5 gallon every now and then just to have a good go to on hand. Was thinking 10 gallon igloo but was not sure if that would be to big with to much headspace for the smaller mashes? I have also heard of people putting aluminum foil over the top of mash to help keep heat from evaporating if there is a lot of head space. Thoughts?
I have a 43 qt Igloo Cube,the blue one from Home Depot. Oddly enough it didn't come with a spout ,but it did have a flat area molded into the base of one side where I drilled one and installed a bulkhead fitting and ball valve, bazooka tube. I brew 5-6 gallon batches (non-BIAB,but considering it). I batch sparge 2x too. I could have gone with a smaller cooler but for the sole purpose of in case I ever want to do a 10 gallon batch ,I already have the mash tun. When I'm not brewing it serves as a very handy brewing equipment storage container that I can stack . I rarely have more than 12 lbs of grain plus 4-5 gallons of water in it at the same time. It keeps mash temps very steady. In fact ,I have had to lift the lid for heat to dissipate rather than have to add hot water to keep a temp. As long as you pour about a gallon of boiling water in to preheat it . It does just fine for what I need it to do.
 
Unless you’re mashing where the ambient temp is quite cold, or your grains are cold, I can’t imagine losing that much heat. You really do have to preheat the mash tun and consider the temp of the grains when calculating strike temp. Even without the sleeping bag I can’t believe you lose that much heat.
 
How much are you stirring at dough-in? Maybe your overall temp is actually lower, but you're measuring in a hot spot and then the temp is equalizing over the course of the mash. I used ot measure in the top center of my mash and my beers were always way dry. I think I was losing heat at the sides perhaps and it wasn't making it to the center (the rest of the mash was cooler than my reading). You might need to stir or something to make sure temps are evenly distributed or something.

How long is your mash period? How long does it take to get full conversion. Note that those are not necessarily the same.

With BIAB you have the ability to use grains that are milled much finer than in a conventional mash tun and with that finer milling, conversion happens much faster and then your temperature loss is of no concern. I've tested my conversion time and found it to be less than 5 minutes. Why should I worry if I happen to lose 5 degrees by the end of the hour?

But once conversion happens, won' the longer dextrins still be broken down into shorter ones if you don't mash-out?
 

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