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General Category => Equipment and Software => Topic started by: gmac on April 07, 2011, 04:57:24 PM

Title: Prepping a cooler
Post by: gmac on April 07, 2011, 04:57:24 PM
I am using a coleman Extreme cooler, 50 quart I believe and I've got a couple questions on how you guys prep these on brew day.
I have seen posts that say they don't lose a degree in the hour you are mashing but today and last time, I left the thermometer in and both times, the final temp was about 10 degrees below the start temp.  For example, today it started at 154 and an hour later the thermometer is reading about 144.  I'm guessing I'm losing a lot of heat to warm the cooler so I'm wondering what you do.  My brews have been thinner than I've wanted and I wonder if this is part of the problem.

All I've been doing is adding a couple quarts of 180 water and sloshing it around a bit and letting it sit for 5 minutes and dumping it. 
Suggestions?
Thanks
Title: Re: Prepping a cooler
Post by: bluesman on April 07, 2011, 04:59:40 PM
Check out Denny's website and let us know if you have any other questions from there.

http://hbd.org/cascade/dennybrew/
Title: Re: Prepping a cooler
Post by: JKL on April 07, 2011, 05:03:44 PM
Wow! 10 deg seems like an awful lot in an hour.  How cold is it where you're at?  I put a pillow on the lid of my round Igloo.  You might want to consider that as well as wrapping it with a blanket or Sleeping bag for extra insulation.
-J.K.L.
Title: Re: Prepping a cooler
Post by: theDarkSide on April 07, 2011, 05:06:36 PM
I usually boil a quart or two of water and dump it in.  I then drain it out the spigot before I start my mash.

Make sure your mash is well stirred up and the temp has had a chance to stabilize.  Is you thermometer a probe type that your can watch from outside or a glass one that you check at the end?

On really cold days, I cover with a thick beach blanket to help insulate.
Title: Re: Prepping a cooler
Post by: a10t2 on April 07, 2011, 05:11:08 PM
For example, today it started at 154 and an hour later the thermometer is reading about 144.  I'm guessing I'm losing a lot of heat to warm the cooler so I'm wondering what you do.

Just add 10 degrees to your strike temperature next time - so in this case, calculate the infusion for a 164°F rest. The exact amount lost to the cooler will change with the mash volume and liquor:grist ratio, but that will definitely get you within a couple degrees.

If you want to get fancy, you can estimate the specific heat capacity of the cooler and - in my experience - hit the mash temperature right on target every time.
Title: Re: Prepping a cooler
Post by: Hokerer on April 07, 2011, 05:12:48 PM
It sounds like your biggest problem is preheating your cooler.  What I do is to just add my strike water 10 or so degrees higher than the calculated strike temp.  That hotter water will preheat to the cooler and I just wait until the water temp drops enough to be equal to the strike temp and that's when I add the grist.

Doing it that way, with my Xtreme, I don't lose any more than 1 degree during the course of a 60 minute mash.
Title: Re: Prepping a cooler
Post by: tonyp on April 07, 2011, 05:17:10 PM
Isn't there an issue with BPA-leaching by putting high-temp or boiling water into a plastic container? Are there BPA-free coolers available? This is one of the only issues stopping me from using one and going all-grain.
Title: Re: Prepping a cooler
Post by: WDE97 on April 07, 2011, 05:25:47 PM
+1 on the higher strike water temp and putting a pillow/towel on top of your cooler.

Something else to consider is to put a towel or something under your cooler.  Cold concrete/tile floors or a stone countertop have a large heat capacity so you can lose a lot of heat from the bottom, not just the top and sides.  I was losing @4F over an hour on my 10gal rubbermaid cooler, then realized how cold my granite countertop felt (and how warm the spot the cooler water sitting on felt). After putting a folded up bath towel under it, I now lose <2F over an hour.
 
Title: Re: Prepping a cooler
Post by: Bret on April 07, 2011, 05:33:48 PM
+1 on the higher strike water temp and putting a pillow/towel on top of your cooler.

Something else to consider is to put a towel or something under your cooler.  Cold concrete/tile floors or a stone countertop have a large heat capacity so you can lose a lot of heat from the bottom, not just the top and sides.  I was losing @4F over an hour on my 10gal rubbermaid cooler, then realized how cold my granite countertop felt (and how warm the spot the cooler water sitting on felt). After putting a folded up bath towel under it, I now lose <2F over an hour.
 
Like camping--most of your body heat is lost down into the ground.
Title: Re: Prepping a cooler
Post by: denny on April 07, 2011, 05:52:38 PM
Isn't there an issue with BPA-leaching by putting high-temp or boiling water into a plastic container? Are there BPA-free coolers available? This is one of the only issues stopping me from using one and going all-grain.

As far as I know, the coolers are HDPE and contain no BPA.  Am I incorrect?
Title: Re: Prepping a cooler
Post by: weithman5 on April 07, 2011, 05:55:10 PM
watch the temperature of your grain prior to dough in.  not that you need to measure it, but if you sometimes have the grain in the house over night and sometimes take it out of the refridgerator just before that can be a 20 plus degree difference and your strike water can lose heat a bit faster than you excpect
Title: Re: Prepping a cooler
Post by: denny on April 07, 2011, 05:56:31 PM
Also, make sure you stir thoroughly and check the temp in different areas of the cooler to be sure it's consistent.  Often when I hear of people losing a lot of temp it's because the temp wasn't even to start with.
Title: Re: Prepping a cooler
Post by: WDE97 on April 07, 2011, 06:01:45 PM
watch the temperature of your grain prior to dough in.  not that you need to measure it, but if you sometimes have the grain in the house over night and sometimes take it out of the refridgerator just before that can be a 20 plus degree difference and your strike water can lose heat a bit faster than you excpect

Another good point.

Is it Palmer's book that has formula's for calculating temperatures and water quantities for mashing, multi-infusions, etc?  One of the variables is grain temperature before you add it to the mash.  I put these formulas into an Excel spreadsheet and it makes calcuating everything really simple on brew day. 
Title: Re: Prepping a cooler
Post by: tygo on April 07, 2011, 06:12:40 PM
Isn't there an issue with BPA-leaching by putting high-temp or boiling water into a plastic container? Are there BPA-free coolers available? This is one of the only issues stopping me from using one and going all-grain.

As far as I know, the coolers are HDPE and contain no BPA.  Am I incorrect?

Rubbermaid coolers are BPA free:  http://www.rubbermaid.com/Pages/LearnAboutBPA.aspx#nobpa

I suspect Coleman coolers are as well but I can't seem to find anything definitive.
Title: Re: Prepping a cooler
Post by: denny on April 07, 2011, 06:19:21 PM
I have a good friend who's a homebrewer and a plastics guy by trade.  He assures me that all the coolers he knows of are HDPE.
Title: Re: Prepping a cooler
Post by: gmac on April 07, 2011, 06:20:09 PM
Thanks all.  I'm betting the problem is my procedure.  I'm adding the cellar temp grain to the "warmed" cooler and then the water.
Next time I'll put in all the water at 180 or 185 and then let it sit and cool down to strike temp and then add the grain.  I didn't think that there'd be a big difference because I'm stirring well and not getting dough balls but clearly I am wrong.

I'll also put a towel under it on the cement floor.
Title: Re: Prepping a cooler
Post by: euge on April 07, 2011, 06:20:40 PM
Quote
Calculating Your Thermal Mass with ProMash
contributed by the_stain

Q: What is the Thermal Mass of my mash tun, and how can I calculate it?
A: Thermal mass is the amount of heat your mash tun will absorb when you add the water. This can affect your calculations a bit when attempting to calculate your strike temperatures.

The default or "average" thermal mass of 0.30 will get you pretty close most of the time, but you can measure it yourself with the following procedure:

1. Go into ProMash and go into the Strike Temp calculator.
2. For Mash Tun Thermal Mass, Enter 0.
3. For Total Grain enter 0.00001 pounds. (It won't let you go any smaller - entering 0 will give you a division error.) This should make your water:grain ratio 120000:1.
4. For Total Water, enter 16.00 quarts.
5. For Desired Strike Temp, enter 170. (You can use any temperature but this will more accurately reflect actual mash temperatures.)
6. For Grain Temp, enter the current room temperature.
7. Heat 16 quarts (4 gallons) of water to 170 degrees and pour it quickly into the mash tun. Close the lid and seal it up, and let it sit for about 5 minutes.
8. Measure the temperature of the water in the mash tun.
9. Enter the temperature of the water in the mash tun in the "Desired Strike Temp" field in ProMash.
10. Now look at the "Initial Strike Water Temp Should Be" window. You will note that, with Thermal Mass set to 0, this number will be the same as the "Desired Strike Temp" field.
11. Now, in small (say 0.1 or smaller) increments, increase the Thermal Mass field until the "Initial Strike Water" field reads 170 (or whatever temperature you started with, if you didn't use 170 for some reason.).
12. Ta-da! Whatever the Thermal Mass field says is your mash tun's thermal mass!

This'll getcha closer to your strike and you won't have to preheat the tun. Theoretically. The temp of the tun matters as well. If you had it in the garage in cold weather or in the house where it's warm there will be a difference when you pour the water in.

Cover your tun with a sleeping bag or comforter. I've always had a mash temp drop. My efforts/hopes are to keep it stable for the first 30 minutes. Then not worry so much...
Title: Re: Prepping a cooler
Post by: tonyp on April 07, 2011, 07:38:33 PM
I have a good friend who's a homebrewer and a plastics guy by trade.  He assures me that all the coolers he knows of are HDPE.

great news, thanks guys, looks like i'l be going all-grain soon!
Title: Re: Prepping a cooler
Post by: Will's Swill on April 09, 2011, 04:31:04 PM
Are y'all talking about temp drop from strike water to end of mash?  As opposed to stabilized temp with water and grist to end of mash?  I admit that I lose 10 - 20 degrees from HLT to stabilized temp, but I lose only about 1 - 2 degrees even over 90 minutes in my Rubbermaid cooler once I've thoroughly doughed-in and closed her up.  And I mash outside even when it's snowing and I routinely leave my cooler on the ground.  And I don't preheat at all.  I also monitor the temp continuously with an oven thermometer with the cord coming out from underneath the lid.

Just curious, because y'all seem to have a lot of heat loss.
Title: Re: Prepping a cooler
Post by: tubercle on April 09, 2011, 08:39:45 PM
Thanks all.  I'm betting the problem is my procedure.  I'm adding the cellar temp grain to the "warmed" cooler and then the water.
Next time I'll put in all the water at 180 or 185 and then let it sit and cool down to strike temp and then add the grain.  I didn't think that there'd be a big difference because I'm stirring well and not getting dough balls but clearly I am wrong.

I'll also put a towel under it on the cement floor.


 That what i do and hit within 2 or 3 degrees every time. It take a while to learn your system. I can bet on having my water about 14f above mash temps. This pre-heats everything and you can get the temps down fairly quick with some stirring before adding grain.
Title: Re: Prepping a cooler
Post by: gmac on April 15, 2011, 01:53:58 AM
Just to bring some closer to my post, this time I added 20 quarts of 185 degree water to my cooler/mash tun.  Left it for 10 minutes and it was down to 171.  Added my grain (note to self - stir while adding next time...Holy grain balls!).
Had to add 2 quarts of cold water to bring it down to 156.  Also elevated the cooler off the floor.
After 1 hour, the mash was reading 154 so it only went down 2 degrees at most.  Clearly my problem was my procedure. Thanks everyone for the suggestions.
Title: Re: Prepping a cooler
Post by: Hokerer on April 15, 2011, 01:56:28 AM
Glad to hear you figured it out.  Thanks for following up.

And yeah, pretty important to stir while adding grain to water :)