Hydrometer and sparge confusion

[james1988]

I've managed to some how confuse myself when it comes to my Hydrometer after my first AG brew. I was talking to a friend of mine the other day about it and he said that when I was taking reading during the sparge that I should have cooled the wort to 20c in the trial jar and then taken the gravity. I was aiming for 23L but got to 1008 by the time I had run off 21L. I was taking the temperature readings at about 66c (from memory). I had read somewhere to stir the wort and take the gravity of it before jugging it back into the boiler - this gave me 1048 which is what I was aiming for but the wort was still around 66c. I've completely confused myself so if somebody could point me in the right direction it would be appreciated. Also the Hydrometer instructions only give temperature adjustments to 30c.

I hope you I've explained myself well enough.
Thanks,
James

 

[markp]

You need to temperature adjust any gravity reading that is not carried out at the same temperature at which your hydrometer is calibrated.
They are calibrated at either 20 degrees or 16 degrees.

Wort is less viscous at higher temperatures, so your hydrometer will read a lower gravity than it actually is.
Conversely, at lower temperatures the wort is more viscous and the gravity will read higher.

You can either cool the wort to the temperature your hyrometer is calibrated at to take the reading or take the reading and adjust it for temperature.

The calibration temperature of your hydrometer should be printed on the bottom of the paper scale.

Hope that un-confuses you :)

 

[james1988]

I'll keep a bucket of ice water next to me next time to cook the wort quickly to 20c. That's probably easier haha

James

 

[Sean_Mc]

I use a refractometer bought off ebay, just a couple of drops of wort and you have a fairly accurate reading quickly with no fuss

 

[MikeB]

I just use the conversion utility on this very website.

 

[WelshPaul]

I just use the conversion utility on this very website.

+1 for that! :thumb:

 

[hairybiker]

I must admit I don't bother to do sparge testing. I sparge to volume and then boil it down. I usually go for 6.5Gal in the boiler to get 5Gal out at the end, never noticed any off flavours doing this.

I usually mash in at 3-3.5Gal for 5-6Kg of malt + adjuncts, then sparge with 5.5Gal of water @ 79deg.

Sorry for mixed measures just the way I work :thumb:

 

[james1988]

I'll have a go at the conversion utility in a bit. Mine only goes as far as 30c