Mash temp accuracy

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QuadConPana

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First, I don't need any links to accurate thermometers. I have been doing Google searches for my question, and have seen all of those. One day, I'll invest in a VERY good thermometer, but not today. And, I don't want to spend $20 on one that is only PRETTY good. There's always more equipment you can buy, and if I stop brewing long enough I could afford an amazing setup right before I die. My next equipment purchase will be related to fermentation temp control. Until that happens, nothing else but ingredient purchases for me. And, I would rather avoid incremental upgrades since that costs more in the long run than buying the good stuff the first time.

I have a long stem thermometer that I bought from MWS. When I calibrate it to 32 in ice water, it reads about 207 in boiling wort. I have no way of knowing if the inaccuracy is proportional throughout the temp range, or if it only gets bad at the high end. So, If I have to mash at say, 158, I'm only sure that I'm probably somewhere between 155-160.

I've done a couple of BIAB batches that were somewhat underwhelming. I've gone back to extract for the last three for pretty good results.

So, my question is, if my mash temp is kind of iffy, do I lose the advantage of WG vs extract? Or, will that kind of temp difference be hard to notice? I expect Briess probably gets the temp right on when they make DME, don't you think? Mind you, I still steep specialty grains for a custom flavor profile.
 
First, I don't need any links to accurate thermometers. I have been doing Google searches for my question, and have seen all of those. One day, I'll invest in a VERY good thermometer, but not today. And, I don't want to spend $20 on one that is only PRETTY good. There's always more equipment you can buy, and if I stop brewing long enough I could afford an amazing setup right before I die. My next equipment purchase will be related to fermentation temp control. Until that happens, nothing else but ingredient purchases for me. And, I would rather avoid incremental upgrades since that costs more in the long run than buying the good stuff the first time.

I have a long stem thermometer that I bought from MWS. When I calibrate it to 32 in ice water, it reads about 207 in boiling wort. I have no way of knowing if the inaccuracy is proportional throughout the temp range, or if it only gets bad at the high end. So, If I have to mash at say, 158, I'm only sure that I'm probably somewhere between 155-160.

I've done a couple of BIAB batches that were somewhat underwhelming. I've gone back to extract for the last three for pretty good results.

So, my question is, if my mash temp is kind of iffy, do I lose the advantage of WG vs extract? Or, will that kind of temp difference be hard to notice? I expect Briess probably gets the temp right on when they make DME, don't you think? Mind you, I still steep specialty grains for a custom flavor profile.

As an engineer (electrical) with a limited knowledge of the construction of thermometers, I would not think that the discrepancy is dynamic across the range of the thermometer.

It is most likely just off a bit from manufacture. I think you could be reasonably comfortable with using 207 as your boiling measurement and just adjusting based on the stated tolerance of the thermometer.
 
I have a long stem thermometer that I bought from MWS. When I calibrate it to 32 in ice water, it reads about 207 in boiling wort. I have no way of knowing if the inaccuracy is proportional throughout the temp range, or if it only gets bad at the high end. So, If I have to mash at say, 158, I'm only sure that I'm probably somewhere between 155-160.

What is your elevation?
 
A target mash temp of 158°F is pretty high, and will likely result in a low fermentability wort, leading to a very malty beer. Is this what you are targeting? More common target temps are in the 152° - 154°F, and in that range a degree or two off will still give good results although maybe a little drier or maltier than intended.

Part of the "underwhelming" issue for your all grain brews may be related to water chemistry. You may be low on chloride (not chlorine) or sulfate, which can affect flavor. You might be too low in calcium, which can affect yeast health and flocculation. Your mash pH might be off. Or, you might have something in the water that gives you off flavors (like chlorine, chloramine, iron, etc.) In extract brewing, the extract manufacturer took care of the water issues for you. With all grain, it's up to you to correct the water if it needs it. Start reading up in the Brew Science area here on HBT and at Bru'n Water.

Brew on :mug:
 
The 207 is at least in part Prob due to altitude. I have missed my temps mash temps. It has not seemed to be as exact science as stated. If it ferments out near expected FG then all is well. One thing, Just check the thermo against another. Any other at a parents house or anything. It's kinda like two minds are better than one, you may both be wrong but probably point closer to the truth. As noted typically mash temp is aimed a little lower but you can play around up there.
 
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