Cooler for mashing...

I just bought a cheap $20 48 qt coleman rectangular cooler to hopefully use for mashing and I decided to do a little test for temperature retention...

So I grabbed a thermocouple meter from work, warmed some water to around 160*F and dumped it in the cooler... First measurements in the cooler was 156.9*F, and after an hour it was 145.2*F..

Is 12*F too much of a drop for mashing? I haven't done any AG yet, and am in the gathering equipment phase...

12F is way too much. You need to keep the temperature within 1 or 2 F. First, you need to heat the cooler up first. So, check the temperature after about 10 minutes and at 60.

I pour boiling water in my cooler and let it sit for 10, then I drain it, toss in the grains, adjust the water temperature & add it back.

It was at 152.9 after 10 minutes, so that's still a 10 degree drop..

Guess I'll return it.. I was looking at the Coleman Extreme's, but I also ordered a normal cooler bulkhead today from Northern Brewer, and the extreme's need the XL...

The Xtreme works great. I preheated before my last mash, the first time with the cooler - I didn't lose a single degree, even in 40 degree ambient temp. Return the bulkhead, get the XL, it fits right in perfectly.

You can use just about anything that'll hold the correct amount of water/grain for a mash tun, assuming you have a means of controlling the temperature. My system is a good Igloo Ice Cube cooler with a recirculating system that will maintain and/or raise the temperature as I desire. That's probably a bit more involved than you want to get, but do a search on decoction mashing if you're having trouble maintaining temps.

It would depend on how much water you dumped in the cooler and if you pre warmed it or not. Keep in mind the grain will hold a better heat than water alone.

I use a 5 gal Coleman cooler with a manifold in the bottom for a mash tun. I fill the cooler with hot tap water about a half hour before I dough in the grain. Just before doughing I dump the tap wter and dough in with water that is about 172 F. After doughing in the temp is usually 152 F. If necessary I adjust with boiling H20 or ice cubes. I stir 2 or 3 times. The temperature remains constant at 152F for an hour. .
I have never tested the the tun with just hot water to see if there is a drop in temp.

If you have an insulated Igloo cooler It should be able to maintain a constant mash temp for an hour if you have the top on tight and you don't open it too many times

Also a lot of the heat seems to go out the lid. If you put a blanket or a couple of towels on the top it helps retain the heat.

I used to have a 48qt IceCube Mash Tun. Its now just a lauter tun becuase I got soo frustrated with trying to figure out its temprature adjustments.

Just thought I would give you some words of discouragment

Dont underestimate the importance of preheating your mash tun, not only does it improve temperature retention through out the mash period it is vital to acheiveing a stable mash temperature as quickly as possible, minimising or eliminating any hot or cold water additions.

A kettle full of near boiling water poured into the MT 10-15mins before mashing does the trick.

Don't worry too much about the large temperature drop at the moment the mash will retain the heat much better than water alone.

It's worth throwing a few blankets or a sleeping bag over the MT to help retain the temperature, it's also worth putting a folded towel under the MT to insulate the bottom from the surface below.

With these simple steps you should acheive a near zero temperature drop throughout a 90 min mash period which will give you far greater control over the resultant beer.

Blender said:

Also a lot of the heat seems to go out the lid. If you put a blanket or a couple of towels on the top it helps retain the heat.

Click to expand...

Here is a tip:

major tip! when using round coolers for mash tuns, remove the plug from inside the lid and fill the lid with expanding insulating foam, these coolers are designed to vent heat to keep the cold in, it is a great design for cold foods, not so great for 158 degrees. leave the plug out until the foam cures, you may have to do this a couple of times ti fill the lid, but it works!

Click to expand...

source:
http://hbd.org/brewery/library/fbbgtba.html

Thanks for all the responses...

I did preheat for about 10 minutes with hot tap water (around 115-120*F). I only used about 3.5 gallons of 160*F water for the test, so maybe the grains would retain heat better too... After the first 10 minutes, and the initial 4*F drop, the drop was nearly linear to 145*F... The lid was pretty hot after an hour, but the sides felt cool to the touch, so it's pretty obvious where the heat loss is from...

I called Northern Brewer to change to the XL bulkhead, he said if it didn't go out yet he'd try to swap it out.. So, depending on what I get in the mail in the next couple of days, I'll either pick up the Coleman Extreme, or maybe look at trying to insulate the lid...

Thanks again... I'm sure I'll have a lot more questions since I'm planning on doing my first AG over the holidays..