Mash thermometer help

[Doctormcbrewdle]

Hey all, I recently bought an Alla thermometer but am having trouble using it. I'm trying to test it in boiling water at the minute next to my digital cheapie in an actual pot on stovetop but can't get it to rise past about 95 degrees?

I try putting just the red tip submerged and the temp changes by a few degrees

 

[Doctormcbrewdle]

How far am I supposed to be submerging this to gain an accurate reading?

 

[gap]

what temperature is the digital thermometer reading?
What is your altitude, it affects boiling temperature.

 

[Doctormcbrewdle]

It reads about 1-2 degrees different. And even then, The glass thermo can go from say, 60 to 56 if I put more or less into the liquid.

Just the 1cm red tip seems accurate, 4 odd cms drops 4 degrees, 8cm in goes back up to where it was with the 1cm submerged so I take it it's either of those two positions?

Website states accurate to within plus or minus 2 degrees. Which is the difference between a light, medium or full bodied mash.. hmm

I can probably gauge it by Beersmith fg over a few brews to see how closely I reach predicted final

 

[MHB]

If you look at the back it will probably say "Total Immersion" that means that the whole thermometer (well at least as far as where you are reading i.e. 100oC) has to be in the liquid.
The heat makes the glass expand, the expanding glass makes the diameter of the tube smaller, the same amount of liquid will rise just enough to be accurate.

Bit of light reading Total Immersion, Partial Immersion, what do these terms mean?
Plenty more info on the www if you want to look.
Mark

 

[Doctormcbrewdle]

Thanks Mark!

You'll laugh, but I was looking at the 'Total Imm' print wondering what "total 1mm" meant (ha)

Thanks for the explanation, will check your link now

 

[Doctormcbrewdle]

Sounds like it would probably be better for me to have a partial immersion type.

 

[trevgale]

It looks the same as one I have that is a total immersion. Also given that I cannot see a partial immersion line this would also indicate it is a total immersion thermometer. This means that it needs to be in the liquid being measured to at least the temperature you are measuring. It makes sense that you are reading a few degrees lower when you only have the bulb in the liquid, you should find the more you immerse it the more accurate it is.

I have one total and one partial thermometer and when used correctly they give the exact same temperature. For measuring liquids I find the partial immersion easier to use as it only requires a small amount to be in the liquid.

 

[Doctormcbrewdle]

Just did a little more testing

It seems to be accurate to my digital thermo if I submerse just short of the temp being read like others have stated. Will do this from now on

Wether or not the digi is accurate is anybody's guess but I've been hitting predicted fg for a long time so seems good

Cheers!