Lesson learned - calibrate thermometers!

Brewed a Centennial Blonde batch on Saturday, no problems. Brewed another batch (AHS Hefeweizen) this morning. I've been using a TruTemp 3518N digital thermometer. When the thing read 224F and my pot wasn't boiling, I figured something was up....

Long story short, I calibrated the digital thermometer against my trusty glass style. The digital one ended up being 12F high. Thus, my mashes and sparges have been way off. So far, no horrifically negative effects in terms of taste. But, consider this a lesson learned.....and a search for a new thermometer.

yea ,I know what u mean, i have three dial thermometers, and none of them read the same, and 2 are the brewmaster series? 20 degrees differance ! so i am back to using the glass style, but i f'd up and droped my only good one last brew!
so time for a new one! hence a good excuse to head to More Beer to see the guys and have a few brews!

Scroll down on the Amazon link you posted and read the reviews for that thermometer. Hindsight doesn't help you, and some of the reveiws are off the wall, but it's a good place to look before making a purchase.





edit:
Try one of these as a back-up thermometer to double check mash temps.

AnOldUR said:

Scroll down on the Amazon link you posted and read the reviews for that thermometer. Hindsight doesn't help you, and some of the reveiws are off the wall, but it's a good place to look before making a purchase.





edit:
Try one of these as a back-up thermometer to double check mash temps.

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yeah, hindsight............

I want a reliable digital thermometer with a probe and cord. I like to be able to have the probe in the water/mash/wort and just watch the digital read out as I walk by. I haven't found one that looks too promising, though I may have to utilize some silicone tubing for a DIY waterproof job.

my lesson - always check the garbage disposal before turning it on. My thermometer made a nice crunch, rattle, rattle, rattle sound as it got around 2 90 degree bends in it.

Strongbad52 said:

my lesson - always check the garbage disposal before turning it on. My thermometer made a nice crunch, rattle, rattle, rattle sound as it got around 2 90 degree bends in it.

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I know it isn't funny, but I LOL'd anyway. That's all you can really do when things like this happen. Kinda like buying 30' of 10/3 wire, installing it, and then realizing you need 30' of 6/3 after you actually plan your electric brewery.

so I started thinking about it, and this could end up being worse than I though. At one point, my thermometer read 228 as it was getting ready to boil. If it was off, say, by 15 degrees, that means I was mashing at ~136 for 60 min and sparging at 160ish for 10-15 min. I thinking that these last two batches aren't going to be all that great - quite bitter though.

I brewed my first AG batch on my new system the other day. didn't calibrate my t.c. and it was 30 deg off mashed around 175 sparged around 200....not good. but I'm still planning on drinking it!!

tomije87 said:

so I started thinking about it, and this could end up being worse than I though. At one point, my thermometer read 228 as it was getting ready to boil. If it was off, say, by 15 degrees, that means I was mashing at ~136 for 60 min and sparging at 160ish for 10-15 min. I thinking that these last two batches aren't going to be all that great - quite bitter though.

Click to expand...

Ive made ~20 or so brews to date. My first 17? Absolutely terrific. The last three, however were mashed with my thermometer also being about 15F off. One was a stout and is still pretty good, but one is an APA that finished at about 1.008 instead of the 1.018 or so I was aiming for. It's pure water, I'm going to dump it.

A lesson I learned several years ago is how long it took my big floating thermometer to actually reach temperature. I'm talking about the big fat ones with a bunch of birdshot in the base. I guess the base of the bulb is deep enough in the lead it takes (by my estimation) about 15 minutes to actually reach temp, which is pretty useless if I am trying to bring anything up or down in temp.

I've got 3 I use including this old beast, and they are all dead on within a degree of each other in both ice water and boiling water. But it took me a while to realize the lag time on the birdshot floater, and I made some mistakes because of it. It takes it several minutes for the temp to penetrate the lead mass and give an accurate reading.

I calibrate every brew day when i fire up the mlt and hlt when it gets around I use a fever thermometer and note the temp diff
when they boil for a while I then adjust to a happy medium
been using blichmann for years with never much of an adjustment needed
but rather than brewing goatpissale (the dog turned it down), I check every time