Author Topic: Digital temp probe  (Read 6923 times)

Offline chasinreno

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Digital temp probe
« on: February 14, 2013, 09:49:37 PM »
I've been thinking I need to control my mash temp more accurately.  SO, I just bought an AcuRight digital probe from Wal-Mart but now I'm wondering how to check it for accuracy.  I've seen temperature requirements to the tenth of a degree!

Offline StatsnBrew

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Re: Digital temp probe
« Reply #1 on: February 15, 2013, 10:34:49 AM »
I calibrate a new thermometer by checking and adjusting it in a bath of crushed ice and water which should be 32 F (0 C) and a pot of boiling water which should be 212 F (100 C).  If the necessary calibration change is different at freezing and boiling points, adjust for the boiling point since that end of the range is much closer to mash temperatures.

If you are at an elevation significantly different from sea level the boiling point will vary as shown here...

http://www.engineeringtoolbox.com/boiling-points-water-altitude-d_1344.html
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Offline chasinreno

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Re: Digital temp probe
« Reply #2 on: February 16, 2013, 11:34:45 AM »
Well, my boiling point at 4000-4500 feet should be 203-204dF but the dial thermometer I've been using reads 198dF, unless wort boils at a lower temp(?).  Maybe that's why my mash efficiency is a little low?  When I run my mash temp up to 155dF it's actually 161dF.

Thanks for the info though.  I'm calibrating today.  :)

Offline chasinreno

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Re: Digital temp probe
« Reply #3 on: February 16, 2013, 12:01:03 PM »
I put my dial temp probe (analog) into water with ice and got about 30dF.  Ok, pretty good.  I then put it into a pot of boiling water; at 4250 Feet elevation it should read 204dF.  It read 199dF, 5dF low. ugh.

I then tested my digital meat temp probe, ( AcuRite - Wal-Mart $14.99 ) which read 32.1dF in ice water and 203.7 to 204dF in boiling water.  Pretty sweet I think, cheap and accurate. I can taste the difference already. :)

The down side is the temp probe alarms at high temperature.  For mash I really need a low temp alarm.  For $14.99 who can complain?

Offline Slurk

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Re: Digital temp probe
« Reply #4 on: February 16, 2013, 12:28:48 PM »
Ad Fundum!

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Offline beernbourbon

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Re: Digital temp probe
« Reply #5 on: February 16, 2013, 11:59:44 PM »
Here's a great link for checking your thermometer. I thought it was as simple as putting it in ice water.....nah baby nah.
I checked it my way, then the way he explains in the video.... 2 degrees difference.

http://www.thermoworks.com/blog/2010/10/making-a-proper-ice-bath/

Not sure how it would work with your elevation difference, but I'm sure you can combine the two and come pretty dang close, eh?
Granted, he is doing this for the particular device he is 'selling' but it applies to all probe thermometers
« Last Edit: February 17, 2013, 12:01:30 AM by beernbourbon »
Primary 1: Nada
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Offline chasinreno

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Re: Digital temp probe
« Reply #6 on: February 27, 2013, 10:27:31 PM »
OK, I got the ice bath all wrong but still got 32.1dF.  That was a really informative demo.  Thanks.

I think I'm going to try a new batch this weekend using my digital temp probe to get exactly 130dF for my dough in then up to 149dF for the bulk of my mash then maybe even a little 156dF to finish it off.
I've also ordered a pH meter to get my mash pH to the exact level.  Wahooo!  80% or BUST(the bank)!
I think my new gear will do the trick.

Offline brewnut

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Re: Digital temp probe
« Reply #7 on: February 28, 2013, 04:07:21 AM »
Chas, I've gone through a couple of those accurite digital thermometers. I think what happened was we pinched the probe wire in the mash tun lid, and started to get wildly inaccurate readings. So be careful with the wire, they seem to be a little fragile.
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Offline beernbourbon

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Re: Digital temp probe
« Reply #8 on: February 28, 2013, 06:44:34 PM »
Chas, I've gone through a couple of those accurite digital thermometers. I think what happened was we pinched the probe wire in the mash tun lid, and started to get wildly inaccurate readings. So be careful with the wire, they seem to be a little fragile.
Yeah....and when you drop the dam thing a couple times, it's back to WallyWorld for a new one......sigh..... Some how my mash reached a temp of oh....somewhere in the neighborhood of about 450 degrees.....  ::)
Primary 1: Nada
Primary 2: Zip
Primary 3: Zilch
Aging: Four hops 60 min IPA #3, #4, #5
Fridge/drinking:Chocolate Milk Stout, Four Hops #1, #2, Bunny Banger 90 min IPA #1, #2, Mowin Down a Thirst,
Next up: Headin' for stout season....