thermometer

[andybrew]

i've got two thermometer one digital one standard. They give me different reading at around 20c by about 4 degrees but both measure boiling water at 99c

how do i know which one is correct or can somebody recommend me an accurate thermometer

Cheers

 

[joe1002]

I have the same, one digital and one glass. The digital thermometer always reads 2-3°c cooler. I have always assumed the glass thermometer is more accurate but I am interested the see the responses to your question :thumb:

 

[jonnymorris]

You get what you pay for, i.e. I wouldn't expect a £5 thermometer, digital or mercury, to be accurate (though I'd put more trust in the glass one in this scenario).

I'll post a link to the digital thermometer I bought when I can find it. I'd swear by it.

Edit: http://www.thermometersuperstore.co..._Waterproof_Digital_Thermometer_1.html#aTAB27

p.s. it's worth distinguishing between 'accuracy' and 'precision'. You can calibrate for accuracy whereas precision relies on the design of the thermometer. The one above can be calibrated and is precise to +/- 0.5 degC.

 

[KIWI]

Hi, I use two digital thermometers, one cheap one which is mounted in a copper pocket I had made, which I can move up and down for different readings.

The other one is a better quality food probe which is very accurate and can be used for quick comparison readings from the top of the mash tun/fermenter or anything its very versatile and gets to temperature very quick.

as long as you use the same thermometer it dosent really matter if it is cheap, as long as you calibrate for its error.

 

[lambert]

I've got a Thermalite 1 and 5, both with calibration certificates. There's a reasonably consistent 1C difference between the two in the "brewing" temps range (20C to 80C). I've also got some cheap thermometers (digital, glass and dial) and their readings are around 4C over OR under the Thermalite readings, but the deviation is not consistent. Which one of the thermometers is correct at 65C to 68C is still mystery :wha:

 

[andybrew]

Jonny how do you calibrate a thermometer I thought about using biking water but with impurities and altitude thought it wouldn't be accurate

 

[jonnymorris]

I think you use ice water as it will remain at 0degC until all the ice has melted. There are instructions with the thermometer but its a while since I did it.

 

[joe1002]

It's on their website:

How to Calibrate the Comark DT400

The DT400 can be calibrated at any time by the user. The procedure is quick and simple:

1. Put some water and crushed ice into a clean mug or water bath (approx 60% crushed ice to 40% water).

2. Insert the thermometer into the ice solution until the stem is covered to at least half way along its length.

3. Wait for the reading to settle.

4. Press and hold the D-H button for 8 seconds to begin calibration.

5. "CAL" will be displayed on the LCD screen and calibration at 0°C will be complete.