40 replies to this topic

[ThroatwobblerMangrove]

Had this problem at a friends house today. I couldn't figure out why the mash temp wasn't even close to what I expected. Tested his thermo in ice water - 74F

[3rd party JKor]

Am I the only one with a calibration station?a bit anal, i know.

Yeah, but which one is right?

[DaKine]

Yeah, but which one is right?

I have to keep 'em within 1 degree C or I can't sleep.

[Trub L]

Yeah, but which one is right?

He plugs all the outputs into a large complex multi-state particle-based optimal estimator. Then he takes a bong hit and just reads the top one.

[DaKine]

He plugs all the outputs into a large complex multi-state particle-based optimal estimator. Then he takes a bong hit and just reads the top one.

or that.

[chuck_d]

I calibrate mine when I think it's off. I use boiling water to calibrate it since it's closer to the temp of the mash, sometimes I calibrate it in an ice bath, too. It's never really been that far off. Usually, it's just fine.

My understanding is that is not the right way to do it. You should use ice water and 32/0, not boiling water and 212/100. How do you know what temperature your boiling water is at?

[Trub L]

My understanding is that is not the right way to do it. You should use ice water and 32/0, not boiling water and 212/100. How do you know what temperature your boiling water is at?

He has a thermome.....oh, I see where you're going with this...

[gnef]

you use your elevation and plug it into a calculator to see what you should be boiling at. It would also be best to use RO or distilled water to remove any solutes. This goes for ice water and boiling, since any solutes will lower the freezing point and increase the boiling point.

[NWPines]

I think the real issue with using ice water (or boiling water for that matter) is that thermometer error is often not linear. A thermo that's off by 2 degrees at freezing won't necessarily be off by 2 degrees at 150. In fact, it's possible for a thermo to read a few degrees off at freezing, but read a few degrees off in the other direction at 150.In my opinion, the best bet is to calibrate your brewing thermometers against a high quality, certified lab thermo at mash temps.FWIW, I use This thermo (the +/- 0.2C version) and have been very happy with it. I've checked it against a hiqh quality lab thermo at mash temp and it's been right on.

[Lonnie Mac]

Am I the only one with a calibration station?a bit anal, i know.

This is just friggin ridiculous!Stop it!So anywho, if I were to send you all my Miljoco's, what do you charge for re-cal?

Edited by Lonnie Mac, 29 March 2009 - 04:39 PM.

[DaKine]

This is just friggin ridiculous!Stop it!So anywho, if I were to send you all my Miljoco's, what do you charge for re-cal?

Send 'em I love to add to the collection.

[chuck_d]

you use your elevation and plug it into a calculator to see what you should be boiling at. It would also be best to use RO or distilled water to remove any solutes. This goes for ice water and boiling, since any solutes will lower the freezing point and increase the boiling point.

Something to consider: The Myth of the Boiling Point

We might say that real boiling requires a good number of bubbles to come through to the surface (instead of getting condensed back as they rise up). But even after this starts, often the temperature continues to rise slowly for some time, going up by at least 0.5°C, sometimes over 1°C. The maximum attainable temperature as the water boils vehemently is a more precise and stable point in each instance, but it is not constant across different circumstances, even under fixed pressure. This makes sense after all, since various factors would affect the rates of inflow and outflow of heat....After full boiling begins the temperature stabilizes around 100°C, then creep up slowly, eventually reaching nearly 101°C.

So, how do you know what temperature your boiling water is?Edit:

In a stainless steel pot, the temperature is much lower, only around 99°C at full boiling.

Edited by chuck_d, 29 March 2009 - 07:10 PM.

[JReigle]

If anyone has a link to a good digital thermometer, please post it.

I have several of these and check them somewhat regularly against themselves in water with crushed ice. They're all within .5F of 32F when I do this and don't seem to drift at all. Unfortunately, they don't have a calibration mode that I can find but don't seem to need it. Works great for mashing, I definitely recommend it.

[ThroatwobblerMangrove]

If anyone has a link to a good digital thermometer, please post it. When I went AG in 2004, I bought a digital thermometer from a cooking site for something like $30. The sucker would drift like it was getting paid for it. Honestly, it would take 5 bloody minutes to finally sit and tell me what the damn temp was. Eventually I got sick of it & bought a analog probe thermo. The guy at the LHBS had a $25 probe thermo that was better than the one I bought and I'm wondering if I should go back and get the better one. Admittedly, I never calibrated the one I've been using which is clearly my fault. Cheers.

I have one that is just a cheap digital thermometer from Walmart or someplace like that. I don't know how accurate it is but it seems pretty reasonable when I'm mashing (the prediction equations are pretty close to what I end up with). I would definitely be interested in something more accurate and maybe something with probe on the end of a wire so I could leave it hanging out in the mash or in my cooling wort.

[Big Nake]

I bounced this around on our local board and someone posted this. I am brewing this morning and I put both of my analogs into my mash water and they were 5° apart! And I just calibrated both of them in a pitcher of snow yesterday! It's always something, you know? I may go for the digital in that link and go for the +/-.04° jobbie.

[Big Nake]

Update: Since I am brewing today, I used both thermos throughout the process to see what was what. During the boil, I placed both of them into a large cup of snow. They both ended up at 32°. My older one (longer probe, smaller dial, no brand name at all) got there first. The new one (a Miljoco from Perfect Brewing here in the area) eventually got there but took longer. At the end of the boil, I put both into the wort after I took it off the burner. The old one showed about 205° and the new one showed about 199°. As the temp dropped, they stayed about 5-6° apart and as I got closer to 60°, they got closer... 5°, 3°, 1°, etc. Eventually, both read about 60°. None of this gives me any real confidence. I may have to splurge for one of these better digitals just to soothe my jangled nerves.

[denny]

I calibrate mine every few brews of it I notice that my FG is consistently high or low. I've had thermometers that would be on at freezing or boiling but off at mash temps, so I now calibrate them at 150F.

[japh]

I've found glass thermometers to be entirely impractical and unsuited for brewing use.

Agreed, the only reason to have a glass thermometer is to have a lab-grade one to calibrate the ones you do use for brewing.

[dagomike]

Right, you never want to use a glass thermo in the brewery, but they make good calibration thermos. Frankly, it doesn't matter what you calibrate to, as long as it's consistent. If 150-degrees today is going to be 150 next week and so on, and you calibrate your entire brewery to that thermo, you're golden.