Refractometer Wort Correction Factor

[AZ Maverick]

I have spent a lot of time learning the use of my refractometer, it gets used for virtually all of my readings during brew day.
I can't remember the last time I used my 'old school' hydrometer - probably to verify the calibration of my refractometer and Tilt hydrometer.
As others have said, I find that when measuring hot wort I have to let the sample cool in the refractometer for at least a minute or two before the reading is stable (and that is using an ATC refractometer).
The only screwy numbers I get are trying to measure mash gravity, but once the grain is cleared the pre-boil gravity is correct.
I haven't spent the time to build various wort correction factor tables, but when comparing the hydrometer readings to the refractometer over various types of worts and running the numbers through the refractometer calculator - I have found that the standard default grab of 1.04 gives me numbers that are withing my acceptable error factor.
The corrected readings I get from my refractometer usually match up to the estimated numbers in Brewsmith within a point or two.
I couldn't live without my refractometer any more on brew days - it makes the process so much easier.

 

[CascadesBrewer]

As others have said, I find that when measuring hot wort I have to let the sample cool in the refractometer for at least a minute or two before the reading is stable (and that is using an ATC refractometer).

Do you put drops of hot wort on the refractometer and then let that sit for a minute+, or do you cool the wort sample first?

 

[AZ Maverick]

Do you put drops of hot wort on the refractometer and then let that sit for a minute+, or do you cool the wort sample first?

I put the hot or boiling drops right on the refractometer and just let it sit for a minute or two.
The reading is pretty stable after that.
The refractometer reads low when the sample is hot, so I just let it sit until the reading stops climbing.

 

[tracer bullet]

The refractometer reads low when the sample is hot, so I just let it sit until the reading stops climbing.

If you don't mind, next time you do this, see if the droplets show any haziness / particulates floating around. When hot and later when cold - i.e. did they move off to the side.

Maybe everyone knows but hydrometers measure density, refractometers measure how light moves through. Particulates make little difference (maybe none) to hydrometers, but have huge effects on refractometers.

 

[balrog]

(maybe none) to hydrometers

I've been on the receiving end of some lively discourse on this topic but I've never tested it myself, as the hydrometer sample is oft times settled mostly by the time I finish pitching and setting up the ferm chamber. Example

I wonder whether for my wheat-centric and no-boil batches whether my data show difference between hydrometer and refractometer consistent with particulates causing (statistical) effect? Something to look into.

 

[VikeMan]

Copied from a post by a soil scientist on a different brewing forum:

"Particles in suspension will alter hydrometer readings. Soil scientists exploit this principle when they use specially calibrated hydrometers to evaluate soil particle size distribution."