How To Measure Temp Of Wort Best

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Bentleigh Brau Haus
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Ferntree Gully - Melbourne
I want to measure the temp of my brewing wort.

I used to just brew and hope for the best (6 yrs or more ago)
for the last 5 or so yrs i have had a light globe in the fridge set to 18-20 deg and it keeps it warm in winter.

The last problem is when a brew kicks off it can get to hot and i have no way of keeping it cool. I feel this may help me brew a better beer.

I will try to use a pelter device under the keg(plastic) to cool it once its to hot. At the moment i have thermocouples and the like in the "air" of the fridge but this is not the true wort temp. I guess the air lags behind the wort temp by some time!

How can i get "true" readings?

thanks for any help

(P.S i dont have any temp device into the wort for fear of contaminating the wort) :chug:
I find the stick-on thermometers seem to be close enough to accurate. I've tested both mine against my digital stem thermometer and the stick-ons are only out by around 1 degree (one was perfect enough, two were out by ~ +1). They give you a general idea of the wort temp which is what you want to know.
ok i may go with the temp sensor stuck to the keg then. I might have 3, one at the top, bottom and middle to see the difference as the cooling effect kicks in, i dont want to have a stone cold bottom and warm top if you understand what i mean.

I am trying this for the use of larger yeasts that want low temps
Tandy sell little electronic thermometers with a probe at the end of a long thin wire.

dangle the probe into the wort, screw the fermenter lid on over the wire, voila, instant wort temp

Jovial Monk
might there be some interaction between the wort and the metal device? (some on the mechanical temp devices have mercury in them)

The electronic ones such as you speek of are i them a thermocouple hence "should" be ok but i can taste the difference with beer in a can, so i wonder if the metal will effect it...

now i'll have to figure a way to control the cooling device with some form of hysteresis so that its not switching on and off constatly. I i have control of the wort temp to within 2 deg i'll be happy as i would think most would... mmmm constanly 18deg beer :rolleyes:
this should get rid of the yest flavours somtimes in home brew beers and really help the larger yeast true?

Another way of improving the beer flavour, profile and category is to rack...

Are you racking?
no i am not because my keg was stolen GRRRR :angry:

but i have planed to buy another (prob is its 30Lt so lots of air in there once i rack) might buy a 20Lt keg to do this!.

once i have the second rack keg, i will try a low temp(costant) with good malt hops etc and rack it, to taste the difference.

You'll find most those thermocouples would be SS coated anyway. If you're using kegs to ferment at the moment whats the difference? Its all SS!

Why dont you just use the 30L and inject some CO2 to clear the headspace in the larger keg?

edit - ignore all that, I just re-read your first post. I thought when you said kegs you meant SS kegs, not plastic fermenters :p
Ben, I use a 25l plastic jerry and a length of plastic tube for racking. Cheap from hardware/kmart with tap already installed. Whole thing takes less than 20 minutes including all sterilising and cleaning up. :ph34r:

I rack into a second fermenter using a length of 12mm tube.
When i rack to my keg or bottling bucket i use a tube with an in-line 13mm plastic irrigation filter - this is to filter out the hops used in dry hopping.

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