[denny]

my feeling is the OG is most difficult to get accurate reading, since you don't get a good mix of the mash and sparge runnings.
[/quote

Wait until it boils, then take a reading.  The boil will mix it.

[homoeccentricus]

my feeling is the OG is most difficult to get accurate reading, since you don't get a good mix of the mash and sparge runnings.
[/quote

Wait until it boils, then take a reading.  The boil will mix it.

My misreadings occurred during the boil. So can I assume the wort is homogeneous at that time, and problems are only caused by temperature?

[Wort-H.O.G.]

my feeling is the OG is most difficult to get accurate reading, since you don't get a good mix of the mash and sparge runnings.
[/quote

Wait until it boils, then take a reading.  The boil will mix it.

My misreadings occurred during the boil. So can I assume the wort is homogeneous at that time, and problems are only caused by temperature?

As soon as wort starts to mix well...right before vigorous boil happens take a sample. I think readings get all squirrelly when you get hot break, hops all floating around your sample that you take reading on.


Sent from my iPad using Tapatalk

[majorvices]

Has anyone noticed that hot wort separates into a low gravity surface layer in the kettle? I experienced this many years ago and now I always collect my FG sample immediately after mixing (whirlpooling) to make sure that it is a uniform and representative sample.

But, isn't the wort substantially mixed during the boil?

[phunhog]

I am glad to see this subject come up. It would seem that through the action of boiling the wort would be the same density throughout. From practical experience though I know that it's not.  If I skim some boiling wort off the top I get a different reading then when I pull a sample from the valve on the bottom of the kettle.  I am guessing temperature has something to do with it but???

[mabrungard]

But, isn't the wort substantially mixed during the boil?

That is exactly what I thought, but of course this is after I've stopped boiling and the wort was still. It seems there is a thin layer of more watery wort near the surface of still wort.

I can only assume that there are some sort of suspended solids in the wort that begin to settle when the wort is still.

[homoeccentricus]

My carefully reached conclusion is that for every single step in the brewing process, there is someone who claims that they have had problems using a refractometer. Shouldn't we ditch that thing?

[HoosierBrew]

I'll say I like a refractometer for pre and post boil measurements.  But part of the discussions here have revolved around taking inaccurate readings on wort that's stratified.  That can happen just as easily with a hydrometer.

[Wort-H.O.G.]

I'll say I like a refractometer for pre and post boil measurements.  But part of the discussions here have revolved around taking inaccurate readings on wort that's stratified.  That can happen just as easily with a hydrometer.

+1 not ditching hydrometer. Once you understand how to use it accurately, it's a great tool. pre and post boil readings with mixed wort is right on with hydrometer....tested it many times.


Sent from my iPad using Tapatalk

[rjharper]

As others have noted, refractometers are temperature sensitive. But wait you cry, my refractometer has ATC (auto temp correction). Well, yes and no. ATC works because the thermal mass of the big block of aluminum and quartz glass at the end of the refractometer, which has been sitting at room temperature, is significantly greater than the single drop of wort you are expected to add to it.

- If you pour a spoonful of boiling wort over the end, it will be too hot and read incorrectly.
- If you leave the refractometer in a hot humid brewery, it will be too hot and read incorrectly.
- If you keep it in your pocket, it will be too hot and read incorrectly.
- If you sit it on your brewstand 6" from the burner, it will be too hot and read incorrectly.
- Conversely, if your brewery or garage is icy cold, it will be too low and read incorrectly.

Bottom line, room temperature refractometer + 1 drop of wort as instructed and no air bubbles in the film = correct reading.

[bengelbrau]

My carefully reached conclusion is that for every single step in the brewing process, there is someone who claims that they have had problems using a refractometer. Shouldn't we ditch that thing?

You can have my refractometer when you pry it from my cold, dead fingers.

[a10t2]

That is exactly what I thought, but of course this is after I've stopped boiling and the wort was still. It seems there is a thin layer of more watery wort near the surface of still wort.

I've seen the same thing and always attributed it (without evidence) to hop oil accumulating on the surface of the wort. As long as I sample (using a syringe and pulling ~0.5 mL, so that it cools almost instantly) a little below the surface I get consistent readings.

[majorvices]

But, isn't the wort substantially mixed during the boil?

That is exactly what I thought, but of course this is after I've stopped boiling and the wort was still. It seems there is a thin layer of more watery wort near the surface of still wort.

I can only assume that there are some sort of suspended solids in the wort that begin to settle when the wort is still.

Interestingly enough I guess I have always had this hunch or fear, which is why I always use a big metal spoon which I plunge into the wort to get my reading.